ISO 19399:2016
(Main)Paints and varnishes — Wedge-cut method for determination of film thickness (scribe and drill method)
Paints and varnishes — Wedge-cut method for determination of film thickness (scribe and drill method)
ISO 19399:2016 specifies a destructive method for determination of the dry film thickness, in which damage to the coat caused in a definite manner is evaluated microscopically. The method is suitable for almost all coat-substrate combinations and also allows determination of the single film thicknesses of coating systems. The method cannot be applied or can only be applied with restrictions in case of - too soft and/or elastic coatings (no recognizable scribe or drill hole can be observed), - hard (cannot be scribed/drilled) or too soft and/or elastic substrates, - too low visual contrast between the coating and substrate, and - film thicknesses that are larger than the depth of field of the measuring microscope.
Peintures et vernis — Détermination de l'épaisseur par la méthode d'entaille en coin (Méthode de rayer et de forage)
L'ISO 19399:2016 spécifie une méthode destructive pour la détermination de l'épaisseur de feuil sec, consistant à évaluer au microscope l'endommagement des couches causé d'une manière définie. Cette méthode convient pour presque toutes les combinaisons de couche/subjectile et permet également de déterminer les épaisseurs individuelles de feuil des systèmes de revêtement. La méthode ne peut pas être appliquée, ou uniquement avec certaines restrictions, dans les cas suivants: - revêtements trop mous et/ou élastiques (aucun trou de pointe ou de foret reconnaissable ne peut être observé); - subjectiles durs (ne pouvant pas être rayés/percés) ou trop mous et/ou élastiques; - contraste visuel trop faible entre le revêtement et le subjectile; et - épaisseurs de feuil supérieures à la profondeur de champ du microscope de mesure.
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INTERNATIONAL ISO
STANDARD 19399
First edition
2016-05-01
Paints and varnishes — Wedge-cut
method for determination of film
thickness (scribe and drill method)
Peintures et vernis — Détermination de l’épaisseur par la méthode
d’entaille en coin (Méthode de rayer et de forage)
Reference number
ISO 19399:2016(E)
©
ISO 2016
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ISO 19399:2016(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
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ISO 19399:2016(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Wedge-cut principle . 2
6 Apparatus . 5
6.1 Method A . 5
6.2 Method B . 7
6.3 Measuring microscope . 8
7 Test specimens. 8
8 Procedure. 8
8.1 Sample preparation . 8
8.2 Number of determinations . 8
8.3 Method A (wedge-cut scribe) . 8
8.4 Method B (wedge-cut bore) . 9
9 Precision . 9
10 Test report . 9
Annex A (informative) Error sources and measuring problems .11
Annex B (informative) Evaluation with tilted specimen .16
Annex C (informative) Evaluation with curved specimen .21
Bibliography .27
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ISO 19399:2016(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 35, Paints and varnishes, Subcommittee SC 9,
General test methods for paints and varnishes.
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INTERNATIONAL STANDARD ISO 19399:2016(E)
Paints and varnishes — Wedge-cut method for
determination of film thickness (scribe and drill method)
1 Scope
This International Standard specifies a destructive method for determination of the dry film thickness,
in which damage to the coat caused in a definite manner is evaluated microscopically. The method is
suitable for almost all coat-substrate combinations and also allows determination of the single film
thicknesses of coating systems.
The method cannot be applied or can only be applied with restrictions in case of
— too soft and/or elastic coatings (no recognizable scribe or drill hole can be observed),
— hard (cannot be scribed/drilled) or too soft and/or elastic substrates,
— too low visual contrast between the coating and substrate, and
— film thicknesses that are larger than the depth of field of the measuring microscope.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 4618, Paints and varnishes — Terms and definitions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4618 and the following apply.
3.1
substrate
surface to which a coating material is applied or is to be applied
[SOURCE: ISO 4618:2014, 2.244]
3.2
coating
layer formed from a single or multiple application of a coating material to a substrate
[SOURCE: ISO 4618:2014, 2.50.1]
3.3
coating system
combination of all coats of coating materials which are to be applied or which have been applied to a
substrate
Note 1 to entry: The actual coating system can be characterized by the number of coats involved.
Note 2 to entry: See also coating (3.2).
[SOURCE: ISO 4618:2014, 2.54]
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ISO 19399:2016(E)
3.4
single coat
part of a coating system
3.5
total film thickness
distance between the surface of the coating and surface of the substrate
3.6
single film thickness
distance between the surface of a single coat and the surface of the coat (substrate) underneath
3.7
dry-film thickness
thickness of a coating remaining on the surface when the coating has hardened
[SOURCE: ISO 2808:2007, 3.5]
3.8
wedge cut
damage to the coating system caused mechanically under the specified angle to the surface and
extending into the substrate
Note 1 to entry: The wedge cut can be implemented as a linear scribe or as a conical bore hole.
3.9
wedge-cut image
microscopic image of a wedge cut
3.10
adhesive failure
detachment of a coating from the substrate caused by external forces
Note 1 to entry: The substrate can be another coating beneath or the basic material.
3.11
cohesion failure
loss of cohesion within a coating caused by external forces
4 Principle
A wedge cut with a known flank angle is made in the coating using a scribing or drilling tool. The
film thickness is calculated from the width of the flank projection of the wedge cut obtained with the
measuring microscope.
5 Wedge-cut principle
The wedge cut for determination of the film thickness according to this International Standard can be
made using a scribing tool (method A) or a drilling tool (method B).
Figure 1 shows a wedge cut according to method A in the cross section. The basis length, l, is the
projection of the wedge-cut flank within the coating and is measured with a microscope between the
upper and lower contrast mark in micrometres.
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ISO 19399:2016(E)
Key
1 coating
2 substrate
3 lower contrast mark (intersection from the substrate to the coating)
4 upper contrast mark
l wedge-cut basis
t dry-film thickness
d
α wedge-cut angle
Figure 1 — Wedge cut according to method A (single coat/cross section)
The film thickness is determined according to Formula (1):
tl=⋅ tan α (1)
d
where
t is the dry-film thickness, in micrometres;
d
l is the wedge-cut base (microscope reading), in micrometres;
tan α is the wedge-cut factor of the wedge-cut tool used.
NOTE 1 Instruments are available where the microscope reading is indicated in “number of scale divisions”
and the wedge-cut factor in “micrometres per scale division”.
NOTE 2 Instruments are available where the microscope reading (in micrometres) for calculating the film
thickness is divided by a divisor assigned to the wedge-cut tool.
The film thickness measuring range is as follows:
— determined by the wedge-cut angle, the dimensions of the wedge-cut tool and the scale measuring
range of the microscope;
— limited by the depth of field of the measuring microscope (see A.9).
The resolution of the dry-film thickness measurement is determined by the wedge-cut angle and the
scale division of the measuring microscope.
EXAMPLE For the usual wedge-cut angles α = 5,7° and α = 14,0°, the following is indicated in Table 1:
— the wedge-cut factor tan α;
— the dry-film thickness measuring range (= scale measuring range × tan α);
— the absolute dry-film thickness resolution Δ (= scale division × tan α);
a
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ISO 19399:2016(E)
— the relative dry-film thickness resolution Δ (= (Δ /t ) × 100; t = dry-film thickness).
r a d d
In the above, it is assumed that the measuring microscope has a scale measuring range of 2 mm, as well
as a scale division of 0,02 mm and that the wedge-cut tool is sufficiently dimensioned.
Table 1 — Numerical data on the wedge-cut method
Wedge-cut angle α ° 5,7 14,0
Wedge-cut factor tan α 0,10 0,25
Film thickness measuring range µm up to 200 up to 500
Absolute film thickness resolution Δ µm 2 5
a
Relative film thickness resolution Δ % 200/t 500/t
r d d
Figure 2 shows a wedge cut according to method B in the cross section (I) and the associated wedge-cut
image (II) visible through the microscope. Here, the section l to be measured with the microscope is the
distance between the concentric circles.
Key
1 cross section
2 wedge-cut image
I coating
II substrate
l wedge-cut basis
t dry-film thickness
d
α wedge-cut angle
Figure 2 — Wedge cut according to method B (single coat)
In the case of coating systems, the single film thicknesses can be determined in a similar manner.
Figure 3 shows the wedge-cut scribe (method A) for a 2-coat system. The single dry-film thicknesses t
d1
and t are then calculated from the microscope readings l and l with Formula (1) for t = l · tan α
d2 1 2 d1 1
and t = l · tan α.
d2 2
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ISO 19399:2016(E)
Key
1 single coat 1
2 single coat 2
3 substrate
l wedge-cut basis associated with t (i = 1, 2)
i di
t dry-film thickness of the single coat i (i = 1, 2)
di
α wedge-cut angle
Figure 3 — Wedge cut according to method A (2-coat system/cross section)
6 Apparatus
6.1 Method A
6.1.1 Wedge-cut scribing device, as shown schematically in Figure 4, with the following features.
6.1.1.1 The stylus 6 is fastened interchangeably in the metal block 7 and protrudes as far out as the
support bolts 3.
NOTE There are wedge-cut scribing devices that are equipped with support wheels instead of the
support bolts.
6.1.1.2 The device shall be adjusted so that, when placed on an even surface, the stylus axis 8 is
oriented vertically to this surface.
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ISO 19399:2016(E)
a) Side view
b) Front view
Key
1 direction of load 5 substrate
2 direction of scribing 6 wedge-cut stylus
3 support bolts 7 metal block
4 coating 8 stylus axis
Figure 4 — Wedge-cut scribing device
6.1.2 Wedge-cut stylus, made from hard metal with a form according to Figure 5, with indication of
the wedge-cut factor and/or the wedge-cut angle.
Key
1 shaft 3 stylus axis
2 cutting edge α wedge-cut angle
Figure 5 — Wedge-cut stylus
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ISO 19399:2016(E)
6.2 Method B
6.2.1 Wedge-cut drilling device, as shown schematically in Figure 6, with the following features.
6.2.1.1 The rotational movement of the drill bit 9 fastened interchangeably in the drilling spindle 4
(see Figure 6) may be generated manually or by an electromotive drive.
6.2.1.2 The device shall be adjusted so that, when placed on an even surface, the drill axis 2 is oriented
vertically to this surface.
Key
1 direction of load 6 support
2 drill axis 7 coating
3 rotational movement 8 substrate
4 drilling spindle with chuck 9 wedge-cut drill bit
5 drilling spindle guide 10 housing
Figure 6 — Wedge-cut drilling device
6.2.2 Wedge-cut drill bit, made from hard metal with a form according to Figure 7, with indication of
the wedge-cut factor and/or the wedge-cut angle.
Key
1 coupling 4 cutting edge
2 shaft 5 drill axis
3 drill head α wedge-cut angle
Figure 7 — Wedge-cut drill
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ISO 19399:2016(E)
6.3 Measuring microscope
Measuring microscope, with illumination device and with
— a minimum of 40x magnification,
— a measuring range of minimum 2 mm, and
— a scale division of maximum 0,02 mm.
NOTE 1 Standard wedge-cut devices are equipped with an integral measuring microscope and an integral
illumination device.
NOTE 2 Instead of a conventional measuring microscope, a video microscope can be used and the wedge-cut
image evaluated digitally.
7 Test specimens
The specimens shall exhibit a planar area, which is at least twice as big as the base plane of the
wedge-cut device.
NOTE 1 Clamping devices are available for wedge-cut drilling devices (method B), which also enable
measurements on specimens with a very small planar area (typical dimensions: 15 mm × 15 mm). Specimens with
complex geometry (e.g. profiles) can also be fastened with these devices for measuring the dry-film thickness of
such specimens.
NOTE 2 Under certain boundary conditions, film thickness determinations on curved specimens are also
possible (see Annex C).
8 Procedure
8.1 Sample preparation
A laminar contrast marking should preferably be applied to the coating in the area in which the
wedge-cut is to be made, so as to make the microscopic measurement easier.
A black permanent felt-tip pen is normally used for bright coatings. A white or silver-coloured paint felt-
tip pen may be used for dark specimens. In this case, the marking coat shall be applied thinly and shall
be fully hardened before making the wedge cut. It shall be ensured that the solvent in the felt-tip pen
does not attack the coating.
8.2 Number of determinations
For each determination of the dry-film thickness, three wedge-cut scribes or wedge-cut drills,
respectively, shall be applied on the test panel. The wedge-cut basis, l, shall be measured for each cut or
each drill at two different test points.
8.3 Method A (wedge-cut scribe)
8.3.1 Insert the wedge-cut stylus (6.1.2) for the intended measuring range according to 6.1.1.1 into the
wedge-cut scribing device (6.1.1) and fix.
8.3.2 Place the scribing device on the coating and pull with a speed of about 10 mm/s over a section of
minimum 10 mm (see Key 2 in Figure 4). When doing so, press down the scribing device so that a scribe
is made down into the substrate.
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ISO 19399:2016(E)
8.3.3 Place the measuring microscope (6.3) on the coating and measure the width of the projection of
the wedge-cut flank from the surface (marking) to the substrate (see Figure 1) transverse to the wedge-
cut scribe at two points of the scribe.
8.3.4 Use the measured values and the wedge-cut factor of the stylus to calculate the dry-film
thicknesses, in micrometres, according to Formula (1).
8.3.5 Repeat implementation steps 8.3.2 to 8.3.4 at two further points on the specimen.
8.3.6 As a result, indicate the mean value, in micrometres, from the six determinations.
8.3.7 To determine the single-dry-film thicknesses of a coating systems, proceed analogously and
according to Clause 5.
8.4 Method B (wedge-cut bore)
8.4.1 Insert the wedge-cut drill bit (6.2.2) for the intended measuring range into the wedge-cut drilling
device (6.2.1) and fix.
8.4.2 Place the drilling device on the coating and lower the rotating drill bit onto the coating. When
doing so, load the drilling spindle axially (see Key 1 in Figure 6) so that the coating is drilled conically
down into the substrate.
8.4.3 Place the measuring microscope (6.3) on the coating and measure the width of the projection of
the wedge-cut flank from the surface (marking) to the substrate (see Figure 2) in a radial direction at two
points of the drill bore cone.
8.4.4 Use the measured values and the wedge-cut factor of the drill bit to calculate the dry-film
thicknesses, in micrometres, according to Formula (1).
8.4.5 Repeat implementation steps 8.3.2 to 8.3.4 at two further points on the specimen.
8.4.6 As a result, indicate the mean value, in micrometres, from the six determinations.
8.4.7 To determine the single-dry-film thicknesses of a coating system, proceed analogously and
according to Clause 5.
9 Precision
Precision data are currently not available.
10 Test report
The test report shall contain at least the following data:
a) all individual details required for identification and characterization of the specimen, i.e. data
1) concerning the coating (manufacturer, product identification, batch number, application
method, drying/hardening conditions, aging/conditioning conditions, etc.), and
2) concerning the substrate (material, thickness, form, dimensions, curvature, etc.);
b) a reference to this International Standard, i.e. ISO 19399;
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ISO 19399:2016(E)
c) the method used (A or B);
d) the wedge-cut tool used (wedge-cut factor/wedge-cut angle);
e) the test results according to 8.3.6, 8.3.7, 8.4.6, or 8.4.7: the dry-film thickness and, if applicable, the
single-dry-film thicknesses, in micrometres;
f) any deviation from the specified test method;
g) any unusual features (anomalies) observed during the test;
h) the name of the inspector and test laboratory;
i) the date of the test.
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ISO 19399:2016(E)
Annex A
(informative)
Error sources and measuring problems
A.1 Soft and/or elastic coating
A.1.1 Phenomenon
Three negative effects can occur in the case of coatings that are too soft and/or too elastic.
— Non-separated cuttings adhering to the wedge cut comprising coating material impair the wedge-
cut image (at least one of the contrast marks not clearly distinct).
— The effective wedge-cut angle is greater than the specified nominal wedge-cut angle due to spring
back of the elastic coating after the scribing/drilling.
— A bulge can be caused at the upper edge of the wedge cut due to plastic deformation of the soft
coating.
A.1.2 Effect
A correct evaluation is not possible in the case of unclearly distinct contrast marks and upon bulge
formation. The dry-film thickness can only be estimated roughly at best.
In the case of an elastic spring back of the coating, too small dry-film thickness values are determined
systematically.
A.1.3 Remedy
In some cases, the mechanical properties of the coating can be optimized by cooling (freezer or cold
spray). The coating surface shall be protected against solvent attack with an aluminium foil when using
cold spray.
In order to avoid the formation of no separated cuttings from coating material, drilling should always be
conducted intermittently, i.e. not in one go, in the case of method B. Blow off the drill cuttings between
the drilling strokes.
A.2 Soft and/or elastic substrate
A.2.1 Phenomenon
Four negative effects can occur in the case of substrates that are too soft and/or too elastic.
— The lower contrast mark is unclearly distinct due to non-separated substrate cuttings adhering to
the wedge cut.
— Long substrate cuttings can cause a coat disbonding in case of tough substrate material (see A.4).
— Spring back of the elastic substrate after scribing/drilling impairs the distinctness of the lower
contrast mark.
— A bulge can be caused at the upper edge of the substrate cone due to plastic deformation of the soft
substrate.
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ISO 19399:2016(E)
A.2.2 Effect
A correct evaluation is not possible in the case of unclearly distinct contrast marks and upon bulge
formation. The dry-film thickness can only be estimated roughly at best.
A.2.3 Remedy
In the case of plastic substrates, the mechanical properties can be optimized by cooling (freezer or cold
spray) in some cases. The coating surface shall be protected against solvent attack with an aluminium
foil if using cold spray.
In order to avoid the formation of non-separated substrate cuttings, drilling should always be conducted
intermittently, i.e. not in one go and as deep into the substrate as possible in the case of method B. Blow
off the drill cuttings between the drilling strokes.
A.3 Hard substrate (that cannot be scribed/drilled)
A.3.1 Phenomenon
In the case of very hard substrate materials (e.g. concrete), the wedge cut cannot be made fully (i.e.
not into the substrate), with the result that the lower contrast mark is absent or only recognizable
indistinctly in the wedge-cut image.
A.3.2 Effect
The wedge cut cannot be evaluated correctly. Only a lower limit can be indicated for the dry-film
thickness at best.
A.3.3 Remedy
Method A: There is no technical solution for the measuring problem.
Method B: The wedge-cut basis, l, can be determined by measuring the entire drill bore cone diameter
and dividing this by two. If the scale measuring range of the microscope is not adequate for this, a drill
bit with a larger wedge-cut angle (but also with lower dry-film thickness resolution) shall be used.
A.4 Wedge-cut with adhesive failure
A.4.1 Phenomenon
The lower part of the wedge-cut flank has broken off due to disbonding. The disbonding is frequently
caused by the formation of long substrate cuttings in the case of substrate materials that are too tough.
A.4.2 Effect
The ascertained dry-film thickness values are systematically too small. Only a lower limit can be
indicated for the dry-film thickness.
A.4.3 Remedy
The disbonding effect is particularly drastic if the wedge-cut tool penetrates the limit between the
coating and substrate. Scribing/drilling should therefore be performed as deeply as possible into the
substrate.
The measures described in A.2 can be helpful if the plastic substrate is tough: Cooling the specimen, as
well as intermittent drilling and blowing the cuttings away, if method B is used.
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ISO 19399:2016(E)
In the case of method B, the edge of the drill bore cone can still be visible in the substrate, although
the coating is absent there. This shall then be used as the lower contrast mark during microscopic
measuring.
A.5 Wedge-cut with cohesive failure
A.5.1 Phenomenon
Parts of the coating have broken off in the upper area of the wedge-cut flank.
A.5.2 Effect
The ascertained film thickness values are systematically too small. Only a lower limit can be indicated
for the dry-film thickness.
A.5.3 Remedy
The breaking off of the coating can only be prevented by careful scribing/drilling.
A.6 Insufficient visual contrast
A.6.1 Phenomenon
The colour/brightness difference between the coating and the substrate or between the single coats of
a coating system is so low that no contrast marks or only unclear contrast marks are recognizable in
the wedge-cut image.
A.6.2 Effect
The wedge cut cannot be evaluated correctly. The dry-film thickness can only be estimated roughly
at best.
A.6.3 Remedy
The problem can be solved in some cases by
— using a high-quality stereo measuring microscope,
— optimizing the illumination equipment (light intensity, lighting geometry, etc.),
— utilizing a metamerism effect (adapted illuminant, monochromatic LED light, etc.),
— using a fluorescence microscope, and
— use of a contrast medium (see also the note in 8.1).
A.7 Surface curvature
A.7.1 Phenomenon
The curvature of the specimen surface causes a distortion of the wedge-cut geometry (see Figure C.1).
In addition, it is not always ensured that the axis of the wedge-cut tool is oriented vertically to the
coating surface (see A.8).
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ISO 19399:2016(E)
A.7.2 Effect
If no further complication (e.g. specimen tilting, see A.8) is superimposed with the influence of the
curvature, the film thickness values calculated with Formula (1) are systematically too small (too large)
in the case of convex (concave) curvature (see Annex C).
A.7.3 Remedy
The problem can only be solved if using method B: If it is ensured (e.g. by a special device) that the drill
axis is oriented vertically to the specimen surface in the area of the wedge cut and the curvature radius
is known, the effect of the curvature can be corrected (see Annex C).
On the other hand, the results of Annex C also provide the option of estimating the minimum permissible
curvature radius for a specified maximum error, for which the standard evaluation with Formula (1) is
still adequate. This applies for both methods (A and B).
A.8 Specimen tilting
A.8.1 Phenomenon
In the case of measurements on non-planar specimens, the specimen normal (see Figure B.2) can be
tilted against the axis of the wedge-cut tool.
A.8.
...
DRAFT INTERNATIONAL STANDARD
ISO/DIS 19399
ISO/TC 35/SC 9 Secretariat: BSI
Voting begins on: Voting terminates on:
2015-04-23 2015-07-23
Paints and varnishes — Wedge-cut method for
determination of film thickness (scribe and drill method)
Peintures et vernis — Détermination de l’épaisseur par la méthode d’entaille en coin (Méthode de rayer et
de forage)
ICS: 87.040
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 19399:2015(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2015
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ISO/DIS 19399:2015(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2015
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
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Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2015 – All rights reserved
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ISO/DIS 19399:2015(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Wedge-cut principle . 2
6.1 Method A . 5
6.2 Method B . 6
6.3 Measuring microscope . 8
8.1 Sample preparation . 9
8.2 Number of determinations . 9
8.3 Method A (wedge-cut scribe) . 9
8.4 Method B (wedge-cut bore) . 9
Annex A (informative) Error sources and measuring problems .11
Annex B (informative) Evaluation with tilted specimen .16
Annex C (informative) Evaluation with curved specimen .21
Bibliography .27
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ISO/DIS 19399:2015(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies
casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 19399 was prepared by Technical Committee ISO/TC 35, Paints and varnishes, Subcommittee SC 9,
General test methods for paints and varnishes.
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DRAFT INTERNATIONAL STANDARD ISO/DIS 19399:2015(E)
Paints and varnishes — Wedge-cut method for
determination of film thickness (scribe and drill method)
1 Scope
The standard specifies a destructive method for determination of the dry film thickness, in which
damage to the coat caused in a definite manner is evaluated microscopically. The method is suitable for
almost all coat-substrate combinations and also allows determination of the individual film thicknesses
of coating systems.
The method cannot be applied or can only be applied with restrictions in case of
— too soft and/or elastic coatings,
— hard (cannot be scribed/drilled) or too soft and/or elastic substrates,
— too low visual contrast between the coating and substrate,
— film thicknesses that are larger than the depth of field of the measuring microscope.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 4618:2014, Paints and varnishes — Terms and definitions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4618 and the following apply.
3.1
substrate
surface to which a coating material is applied or is to be applied
[SOURCE: ISO 4618:2014, 2.244]
3.2
coating
layer formed from a single or multiple application of a coating material to a substrate
[SOURCE: ISO 4618:2014, 2.50.1]
coating system
combination of all coats of coating materials which are to be applied or which have been applied to a
substrate
Note 1 to entry: The actual coating system can be characterized by the number of coats involved.
Note 2 to entry: See also coating.
[SOURCE: ISO 4618:2014, 2.54]
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ISO/DIS 19399:2015(E)
3.4
individual coat
part of a coating system
3.5
total film thickness
distance between the surface of the coating and surface of the substrate
3.6
individual film thickness
distance between the surface of an individual coat and the surface of the coat (substrate) underneath
3.7
dry-film thickness
thickness of a coating remaining on the surface when the coating has hardened
[SOURCE: ISO 2808:2007, 3.5]
3.8
wedge cut
damage to the coating system caused mechanically under the specified angle to the surface and extending
into the substrate
Note 1 to entry: The wedge cut can be implemented as a linear scribe or as a conical bore hole.
3.9
wedge-cut image
microscopic image of a wedge cut
3.10
adhesive failure
detachment of a coating from the substrate caused by external forces
Note 1 to entry: The substrate can be another coating beneath or the basic material.
[SOURCE: ISO/DTR 19402:2015, 3.3]
3.11
cohesion failure
loss of cohesion within a coating caused by external forces
[SOURCE: ISO/DTR 19402:2015, 3.4]
4 Principle
A wedge cut with a known flank angle is made in the coating using a scribing drilling tool. The film
thickness is calculated from the width of the flank projection of the wedge cut obtained with the
measuring microscope.
5 Wedge-cut principle
The wedge cut for determination of the film thickness according to this standard can be made using a
scribing tool (method A) or a drilling tool (method B).
Figure 1 shows a wedge cut according to method A in the cross section. The basis section l is the
projection of the wedge-cut flank within the coating and is measured with a microscope between the
upper and lower contrast mark in micrometres.
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ISO/DIS 19399:2015(E)
Key
1 Coating
2 Substrate
3 Lower contrast mark (intersection from the substrate to the coating)
4 Upper contrast mark
l Wedge-cut basis
t dry-film thickness
d
α Wedge-cut angle
Figure 1 — Wedge cut according to method A (single coat/cross section)
The film thickness is determined according to Formula 1:
tl=⋅tanα (1)
d
where
t is the dry-film thickness, in micrometres
d
l is the wedge-cut base (microscope reading), in micrometres
tan α is the wedge-cut factor of the wedge-cut tool used
NOTE 1 Instruments are available where the microscope reading is indicated in “number of scale divisions”
and the wedge-cut factor in “micrometres per scale division”.
NOTE 2 Instruments are available where the microscope reading (in micrometres) for calculating the film
thickness is divided by a divisor assigned to the wedge-cut tool.
The film thickness measuring range is
— determined by the wedge-cut angle, the dimensions of the wedge-cut tool and the scale measuring
range of the microscope;
— limited by the depth of field of the measuring microscope (see A.9).
The resolution of the dry-film thickness measurement is determined by the wedge-cut angle and the
scale division of the measuring microscope.
EXAMPLE For the usual wedge-cut angles α = 5,7° and α = 14,0°, the following is indicated in Table 1
— the wedge-cut factor tan α,
— the dry-film thickness measuring range (= scale measuring range × tan α),
— the absolute dry-film thickness resolution Δ (= scale division × tan α),
a
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ISO/DIS 19399:2015(E)
— the relative dry-film thickness resolution Δ (= (Δ / t ) × 100; t = dry-film thickness).
r a d d
In the above, it is assumed that the measuring microscope has a scale measuring range of 2 mm as well
as a scale division of 0,02 mm and that the wedge-cut tool is sufficiently dimensioned.
Table 1 — – Numerical data on the wedge-cut method
Wedge-cut angle α ° 5,7 14,0
Wedge-cut factor tan α 0,10 0,25
Film thickness measuring range µm up to 200 up to 500
Absolute film thickness resolution Δ µm 2 5
a
Relative film thickness resolution Δ % 200 / t 500 / t
r d d
Figure 2 shows a wedge cut according to method B in the cross section (I) and the associated wedge-cut
image (II) visible through the microscope. Here the section l to be measured with the microscope is the
distance between the concentric circles.
Key
I Cross section
II Wedge-cut image
1 Coating
2 Substrate
l Wedge-cut basis
t Dry-film thickness
d
α Wedge-cut angle
Figure 2 — Wedge cut according to method B (single coat)
In the case of coating systems, the individual film thicknesses can be determined in a similar manner:
Figure 3 shows the wedge-cut scribe (method A) for a 2-coat system. The individual dry-film
thicknesses t and t are then calculated from the microscope readings l and l with Formula 1 for
d1 d2 1 2
t = l · tan α and t = l · tan α.
d1 1 d2 2
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ISO/DIS 19399:2015(E)
Key
1 Single coat 1
2 Single coat 2
3 Substrate
l Wedge-cut basis associated with t (i = 1, 2)
i di
t Dry-film thickness of the individual coat i (i = 1, 2)
di
α Wedge-cut angle
Figure 3 — Wedge cut according to method A (2-coat system / cross section)
6 Apparatus
6.1 Method A
6.1.1 Wedge-cut scribing device, as shown schematically in Figure 4, with the following features:
6.1.1.1 The stylus 6 is fastened interchangeably in the metal block 7 and protrudes as far out as the
support bolts 3.
NOTE There are wedge-cut scribing devices that are equipped with support wheels instead of the support
bolts.
6.1.1.2 The device shall be adjusted so that, when placed on an even surface, the stylus axis 8 is oriented
vertically to this surface.
a) Side view
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ISO/DIS 19399:2015(E)
b) Front view
Key
1 Direction of load
2 Direction of scribing
3 Support bolts
4 Coating
5 Substrate
6 Wedge-cut stylus
7 Metal block
8 Stylus axis
Figure 4 — – Wedge-cut scribing device
6.1.2 Wedge-cut stylus, made from hard metal with a form according to Figure 5, with indication of the
wedge-cut factor and/or the wedge-cut angle.
Key
1 Shaft
2 Cutting edge
3 Stylus axis
α Wedge-cut angle
Figure 5 — – Wedge-cut stylus
6.2 Method B
6.2.1 Wedge-cut drilling device, as shown schematically in Figure 6, with the following features:
6.2.1.1 The rotational movement of the drill bit 9 fastened interchangeably in the drilling spindle 4 (see
Figure 6) may be generated manually or by an electromotive drive.
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ISO/DIS 19399:2015(E)
6.2.1.2 The device shall be adjusted so that, when placed on an even surface, the drill axis 2 is oriented
vertically to this surface.
Key
1 Direction of load
2 Drill axis
3 Rotational movement
4 Drilling spindle with chuck
5 Drilling spindle guide
6 Support
7 Coating
8 Substrate
9 Wedge-cut drill bit
10 Housing
Figure 6 — – Wedge-cut drilling device
6.2.2 Wedge-cut drill bit, made from hard metal with a form according to Figure 7, with indication of
the wedge-cut factor and/or the wedge-cut angle.
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ISO/DIS 19399:2015(E)
Key
1 Coupling
2 Shaft
3 Drill head
4 Cutting edge
5 Drill axis
α Wedge-cut angle
Figure 7 — Wedge-cut drill
6.3 Measuring microscope
Measuring microscope, with illumination device and with
— minimum × 40 magnification,
— a measuring range of minimum 2 mm,
— a scale division of maximum 0,02 mm.
NOTE 1 Standard wedge-cut devices are equipped with an integral measuring microscope and an integral
illumination device.
NOTE 2 Instead of a conventional measuring microscope, a video microscope can be used and the wedge-cut
image evaluated digitally.
7 Test specimens
The specimens shall exhibit a planar area, which is at least twice as big as the base plane of the wedge-
cut device.
NOTE 1 Clamping devices are available for wedge-cut drilling devices (method B), which also enable
measurements on specimens with a very small planar area (typical dimensions: 15 mm × 15 mm). Specimens with
complex geometry (e.g. profiles) can also be fastened with these devices for measuring the dry-film thickness of
such specimens.
NOTE 2 Under certain boundary conditions, film thickness determinations on curved specimens are also
possible (see Annex C).
8 Procedure
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ISO/DIS 19399:2015(E)
8.1 Sample preparation
A laminar contrast marking should preferably be applied to the coating in the area in which the wedge-
cut is to be made, so as to make the microscopic measurement easier.
NOTE A black permanent felt-tip pen is normally used for bright coatings. A white or silver-coloured paint
felt-tip pen may be used for dark specimens. In this case, the marking coat shall be applied thinly and shall be fully
hardened before making the wedge cut. It shall be ensured that the solvent in the felt-tip pen does not attack the
coating.
8.2 Number of determinations
For each determination of the dry-film thickness, three wedge-cut scribes or wedge-cut drills,
respectively, shall be applied on the test panel. The wedge-cut basis l shall be measured for each cut or
each drill at two different test points.
8.3 Method A (wedge-cut scribe)
8.3.1 Insert the wedge-cut stylus (6.1.2) for the intended measuring range according to 6.1.1.1 into the
wedge-cut scribing device (6.1.1) and fix.
8.3.2 Place the scribing device on the coating and pull with a speed of about 10 mm/s over a section of
minimum 10 mm (see arrow 2 in Figure 4). When doing so, press down the scribing device so that a scribe
is made down into the substrate.
8.3.3 Place the measuring microscope (6.3) on the coating and measure the width of the projection of
the wedge-cut flank from the surface (marking) to the substrate (see Figure 1) transverse to the wedge-
cut scribe at two points of the scribe.
8.3.4 Use the measured values and the wedge-cut factor of the stylus to calculate the dry-film thicknesses,
in micrometres, according to Formula 1.
8.3.5 Repeat implementation steps 8.3.2 to 8.3.4 at two further points on the specimen.
8.3.6 As a result, indicate the mean value, in micrometres, from the six determinations.
8.3.7 To determine the single-dry-film thicknesses of a coating systems, proceed analogously and
according to Clause 5.
8.4 Method B (wedge-cut bore)
8.4.1 Insert the wedge-cut drill bit (6.2.2) for the intended measuring range into the wedge-cut drilling
device (6.2.1) and fix.
8.4.2 Place the drilling device on the coating and lower the rotating drill bit onto the coating. When
doing so, load the drilling spindle axially (see arrow 1 in Figure 6) so that the coating is drilled conically
down into the substrate.
8.4.3 Place the measuring microscope (6.3) on the coating and measure the width of the projection of
the wedge-cut flank from the surface (marking) to the substrate (see Figure 2) in a radial direction at two
points of the drill bore cone.
8.4.4 Use the measured values and the wedge-cut factor of the drill bit to calculate the dry-film
thicknesses, in micrometres, according to Formula 1.
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ISO/DIS 19399:2015(E)
8.4.5 Repeat implementation steps 8.3.2 to 8.3.4 at two further points on the specimen.
8.4.6 As a result, indicate the mean value, in micrometres, from the six determinations.
8.4.7 To determine the single-dry-film thicknesses of a coating system, proceed analogously and
according to Clause 5.
9 Precision
Data on the precision is not available at present.
10 Test report
The test report shall contain at least the following data:
a) all individual details required for identification and characterization of the specimen, i.e. data
1) concerning the coating (manufacturer, product identification, batch number, application
method, drying/hardening conditions, aging/conditioning conditions, etc.),
2) concerning the substrate (material, thickness, form, dimensions, curvature, etc.);
b) a reference to this International Standard (ISO 19399);
c) the method used (A or B);
d) the wedge-cut tool used (wedge-cut factor/wedge-cut angle);
e) the test results according to 8.3.6, 8.3.7, 8.4.6 or 8.4.7: the dry-film thickness and, if applicable, the
single-dry-film thicknesses, in micrometres;
f) any deviation from the specified test method;
g) any unusual features (anomalies) observed during the test;
h) the name of the inspector and test laboratory;
i) the date of the test.
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ISO/DIS 19399:2015(E)
Annex A
(informative)
Error sources and measuring problems
A.1 Soft and/or elastic coating
A.1.1 Phenomenon
Three negative effects can occur in the case of coatings that are too soft and/or too elastic:
— Non-separated cuttings adhering to the wedge cut comprising coating material impair the wedge-
cut image (at least one of the contrast marks not clearly distinct).
— The effective wedge-cut angle is greater than the specified nominal wedge-cut angle due to spring
back of the elastic coating after the scribing/drilling.
— A bulge can be caused at the upper edge of the wedge cut due to plastic deformation of the soft
coating.
A.1.2 Effect
— A correct evaluation is not possible in the case of unclearly distinct contrast marks and upon bulge
formation. The dry-film thickness can only be estimated roughly at best.
— In the case of an elastic spring back of the coating, too small dry-film thickness values are determined
systematically.
A.1.3 Remedy
In some cases, the mechanical properties of the coating can be optimised by cooling (freezer or cold
spray). The coating surface shall be protected against solvent attack with an aluminium foil when using
cold spray.
In order to avoid the formation of no separated cuttings from coating material, drilling should always be
conducted intermittently, i.e. not in one go, in the case of method B. Blow off the drill cuttings between
the drilling strokes.
A.2 Soft and/or elastic substrate
A.2.1 Phenomenon
Four negative effects can occur in the case of substrates that are too soft and/or too elastic:
— The lower contrast mark is unclearly distinct due to non-separated substrate cuttings adhering to
the wedge cut.
— Long substrate cuttings can cause a coat disbonding in case of tough substrate material (see A.4).
— Spring back of the elastic substrate after scribing/drilling impairs the distinctness of the lower
contrast mark.
— A bulge can be caused at the upper edge of the substrate cone due to plastic deformation of the soft
substrate.
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ISO/DIS 19399:2015(E)
A.2.2 Effect
A correct evaluation is not possible in the case of unclearly distinct contrast marks and upon bulge
formation. The dry-film thickness can only be estimated roughly at best.
A.2.3 Remedy
In the case of plastic substrates, the mechanical properties can be optimised by cooling (freezer or cold
spray) in some cases. The coating surface shall be protected against solvent attack with an aluminium
foil if using cold spray.
In order to avoid the formation of non-separated substrate cuttings, drilling should always be conducted
intermittently, i.e. not in one go and as deep into the substrate as possible in the case of method B. Blow
off the drill cuttings between the drilling strokes.
A.3 Hard substrate (that cannot be scribed/drilled)
A.3.1 Phenomenon
In the case of very hard substrate materials (e.g. concrete), the wedge cut cannot be made fully (i.e.
not into the substrate), with the result that the lower contrast mark is absent or only recognizable
indistinctly in the wedge-cut image.
A.3.2 Effect
The wedge cut cannot be evaluated correctly. Only a lower limit can be indicated for the dry-film
thickness at best.
A.3.3 Remedy
— Method A: There is no technical solution for the measuring problem.
— Method B: The wedge-cut basis l can be determined by measuring the entire drill bore cone diameter
and dividing this by 2. If the scale measuring range of the microscope is not adequate for this, a drill
bit with a larger wedge-cut angle (but also with lower dry-film thickness resolution) shall be used.
A.4 Wedge-cut with adhesive failure
A.4.1 Phenomenon
The lower part of the wedge-cut flank has broken off due to disbonding. The disbonding is frequently
caused by the formation of long substrate cuttings in the case of substrate materials that are too tough.
A.4.2 Effect
The ascertained dry-film thickness values are systematically too small. Only a lower limit can be
indicated for the dry-film thickness.
A.4.3 Remedy
The disbonding effect is particularly drastic if the wedge-cut tool penetrates the limit between the
coating and substrate. Scribing/Drilling should therefore be performed as deeply as possible into the
substrate.
The measures described in A.2 can be helpful if the plastic substrate is tough: Cooling the specimen as
well as intermittent drilling and blowing the cuttings away, if method B is used.
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ISO/DIS 19399:2015(E)
In the case of method B, the edge of the drill bore cone can still be visible in the substrate, although the
coating is absent there. This shall then be used as the lower contrast mark during microscopic measuring.
A.5 Wedge-cut with cohesive failure
A.5.1 Phenomenon
Parts of the coating have broken off in the upper area of the wedge-cut flank.
A.5.2 Effect
The ascertained film thickness values are systematically too small. Only a lower limit can be indicated
for the dry-film thickness.
A.5.3 Remedy
The breaking off of the coating can only be prevented by careful scribing/drilling.
Insufficient visual contrast
A.5.4 Phenomenon
The colour/brightness difference between the coating and the substrate or between the individual coats
of a coating system is so low that no contrast marks or only unclear contrast marks are recognizable in
the wedge-cut image.
A.5.5 Effect
The wedge cut cannot be evaluated correctly. The dry-film thickness can only be estimated roughly at
best.
A.5.6 Remedy
The problem can be solved in some cases by
— using a high-quality stereo measuring microscope,
— optimising the illumination equipment (light intensity, lighting geometry, etc.),
— utilizing a metamerism effect (adapted illuminant, monochromatic LED light, etc.),
— using a fluorescence microscope,
— use of a contrast marker (see also the note in 8.1).
A.6 Surface curvature
A.6.1 Phenomenon
The curvature of the specimen surface causes a distortion of the wedge-cut geometry (see Figure C.1). In
addition, it is not always ensured that the axis of the wedge-cut tool is oriented vertically to the coating
surface (see A.8).
A.6.2 Effect
If no further complication (e.g. specimen tilting, see A.8) is superimposed with the influence of the
curvature, the film thickness values calculated with Formula 1 are systematically too small (too large)
in the case of convex (concave) curvature (see Annex C).
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ISO/DIS 19399:2015(E)
A.6.3 Remedy
The problem can only be solved if using method B: If it is ensured (e.g. by a special device) that the drill
axis is oriented vertically to the specimen surface in the area of the wedge cut, and the curvature radius
is known, the effect of the curvature can be corrected (see Annex C).
On the other hand, the results of Annex C also provide the option of estimating the minimum permissible
curvature radius for a specified maximum error, for which the standard evaluation with Formula 1 is
still adequate. This applies for both methods (A and B).
A.7 Specimen tilting
A.7.1 Phenomenon
In the case of measurements on non-planar specimens, the specimen normal (see Figure B.2) can be
tilted against the axis of the wedge-cut tool.
A.7.2 Effect
— Method A: The tilt effect cannot be seen from the wedge-cut image. The evaluation reveals –
depending on the direction of the tilt – dry-film thickness values that are systematically too small
or too large.
— Method B: The tilt effect is clearly discernible in the wedge-cut image, as ellipses inside one another
are visible instead of concentric circles (see Figure B.1).
A.7.3 Remedy
— Method A: The systematic error caused by the tilt cannot be corrected as it is not recognized.
— Method B: Two measuring values can be read off from the ellipsis constellation (see Figure B.1),
which enable calculation of the film thickness (see Annex B).
NOTE The dry-film thickness can only be determined if the tilt angle is less than the wedge-cut angle.
A.8 Film thickness greater than the depth of field of the measuring microscope
A.8.1 Phenomenon
If the dry-film thickness is greater than the depth of field of t
...
NORME ISO
INTERNATIONALE 19399
Première édition
2016-05-01
Peintures et vernis — Détermination
de l’épaisseur par la méthode
d’entaille en coin (Méthode de rayer et
de forage)
Paints and varnishes — Wedge-cut method for determination of film
thickness (scribe and drill method)
Numéro de référence
ISO 19399:2016(F)
©
ISO 2016
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ISO 19399:2016(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2016, Publié en Suisse
Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite ni utilisée
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copyright@iso.org
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ii © ISO 2016 – Tous droits réservés
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ISO 19399:2016(F)
Sommaire Page
Avant-propos .iv
1 Domaine d’application . 1
2 Références normatives . 1
3 Termes et définitions . 1
4 Principe . 2
5 Principe de l’entaille en coin . 2
6 Appareillage . 5
6.1 Méthode A . 5
6.2 Méthode B . 7
6.3 Microscope de mesure . 8
7 Éprouvettes . 8
8 Mode opératoire. 8
8.1 Préparation de l’échantillon . 8
8.2 Nombre de déterminations . 9
8.3 Méthode A (pointe d’entaille en coin) . 9
8.4 Méthode B (alésage d’entaille en coin) . 9
9 Fidélité .10
10 Rapport d’essai .10
Annexe A (informative) Sources d’erreur et problèmes de mesure .11
Annexe B (informative) Évaluation avec une éprouvette inclinée .16
Annexe C (informative) Évaluation avec une éprouvette incurvée .21
Bibliographie .27
© ISO 2016 – Tous droits réservés iii
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ISO 19399:2016(F)
Avant-propos
L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes
nationaux de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est
en général confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude
a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,
gouvernementales et non gouvernementales, en liaison avec l’ISO participent également aux travaux.
L’ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui
concerne la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont
décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier, de prendre note des différents
critères d’approbation requis pour les différents types de documents ISO. Le présent document a été
rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2 (voir www.
iso.org/directives).
L’attention est appelée sur le fait que certains des éléments du présent document peuvent faire l’objet de
droits de propriété intellectuelle ou de droits analogues. L’ISO ne saurait être tenue pour responsable
de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant
les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de
l’élaboration du document sont indiqués dans l’Introduction et/ou dans la liste des déclarations de
brevets reçues par l’ISO (voir www.iso.org/brevets).
Les appellations commerciales éventuellement mentionnées dans le présent document sont données
pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un
engagement.
Pour une explication de la signification des termes et expressions spécifiques de l’ISO liés à
l’évaluation de la conformité, ou pour toute information au sujet de l’adhésion de l’ISO aux principes
de l’OMC concernant les obstacles techniques au commerce (OTC), voir le lien suivant: Avant-propos —
Informations supplémentaires.
Le comité chargé de l’élaboration du présent document est l’ISO/TC 35, Peintures et vernis, sous-comité
SC 9, Méthodes générales d’essais des peintures et vernis.
iv © ISO 2016 – Tous droits réservés
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NORME INTERNATIONALE ISO 19399:2016(F)
Peintures et vernis — Détermination de l’épaisseur par la
méthode d’entaille en coin (Méthode de rayer et de forage)
1 Domaine d’application
La présente Norme internationale spécifie une méthode destructive pour la détermination de
l’épaisseur de feuil sec, consistant à évaluer au microscope l’endommagement des couches causé d’une
manière définie. Cette méthode convient pour presque toutes les combinaisons de couche/subjectile et
permet également de déterminer les épaisseurs individuelles de feuil des systèmes de revêtement.
La méthode ne peut pas être appliquée, ou uniquement avec certaines restrictions, dans les cas suivants:
— revêtements trop mous et/ou élastiques (aucun trou de pointe ou de foret reconnaissable ne peut
être observé);
— subjectiles durs (ne pouvant pas être rayés/percés) ou trop mous et/ou élastiques;
— contraste visuel trop faible entre le revêtement et le subjectile; et
— épaisseurs de feuil supérieures à la profondeur de champ du microscope de mesure.
2 Références normatives
Les documents suivants, en tout ou partie, sont référencés de façon normative dans le présent document
et sont indispensables pour son application. Pour les références datées, seule l’édition citée s’applique.
Pour les références non datées, la dernière édition du document de référence s’applique (y compris les
éventuels amendements).
ISO 4618, Peintures et vernis — Termes et définitions
3 Termes et définitions
Pour les besoins du présent document, les termes et définitions donnés dans l’ISO 4618 ainsi que les
suivants, s’appliquent.
3.1
subjectile
surface d’application d’un produit de peinture
[SOURCE: ISO 4618:2014, 2.244]
3.2
revêtement
dépôt constitué d’une ou de plusieurs applications d’un produit de peinture sur un subjectile
[SOURCE: ISO 4618:2014, 2.50.1]
3.3
système de revêtement
ensemble des couches de produits de peinture qui ont été appliquées, ou vont être appliquées, sur un
subjectile
Note 1 à l’article: Le système de revêtement peut être caractérisé par son nombre de couches.
Note 2 à l’article: Voir aussi revêtement (3.2).
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[SOURCE: ISO 4618:2014, 2.54]
3.4
couche
partie d’un système de revêtement
3.5
épaisseur totale de feuil
distance entre la surface du revêtement et la surface du subjectile
3.6
épaisseur individuelle de feuil
distance entre la surface d’une couche et la surface de la couche (subjectile) en dessous
3.7
épaisseur de feuil sec
épaisseur de matériau de revêtement restant sur la surface lorsque le produit a durci
[SOURCE: ISO 2808:2007, 3.5]
3.8
entaille en coin
endommagement du système de revêtement causé mécaniquement sur la surface, selon un angle
spécifié, et pénétrant le subjectile
Note 1 à l’article: L’entaille en coin peut être réalisée sous la forme d’une rayure linéaire ou d’un trou conique.
3.9
image de l’entaille en coin
image d’une entaille en coin vue au microscope
3.10
défaut d’adhérence
détachement du revêtement du subjectile causé par des forces externes
Note 1 à l’article: Le subjectile peut être constitué par un autre revêtement en dessous ou par le matériau de base.
3.11
défaut de cohésion
perte de cohésion dans un revêtement causée par des forces externes
4 Principe
Une entaille en coin ayant un angle de flanc connu est pratiquée dans le revêtement au moyen d’un outil
de rayage ou d’un outil de perçage. L’épaisseur de feuil est calculée à partir de la largeur de la projection
du flanc de l’entaille en coin obtenue avec le microscope de mesure.
5 Principe de l’entaille en coin
L’entaille en coin utilisée pour la détermination de l’épaisseur de feuil conformément à la présente
Norme internationale peut être réalisée au moyen d’un outil de rayage (méthode A) ou d’un outil de
perçage (méthode B).
La Figure 1 représente une entaille en coin réalisée avec la méthode A dans la section transversale. La
longueur de base, l, est la projection du flanc de l’entaille en coin dans le revêtement et elle est mesurée
avec un microscope entre les repères de contraste supérieur et inférieur, en micromètres.
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Légende
1 revêtement
2 subjectile
3 repère de contraste inférieur (intersection entre le subjectile et le revêtement)
4 repère de contraste supérieur
l base de l’entaille en coin
t épaisseur de feuil sec
d
α angle de l’entaille en coin
Figure 1 — Entaille en coin selon la méthode A (une seule couche/section transversale)
L’épaisseur de feuil est déterminée selon la Formule (1):
tl=⋅ tan α (1)
d
où
t est l’épaisseur de feuil sec, en micromètres;
d
l est la base de l’entaille en coin (valeur lue sur le microscope), en micromètres;
tan α est le facteur d’entaille en coin de l’outil d’entaille en coin utilisé.
NOTE 1 Sur certains instruments, la valeur lue sur le microscope est indiquée en «nombre de divisions
d’échelle» et le facteur d’entaille en coin en «micromètres par division d’échelle».
NOTE 2 Sur certains instruments, la valeur lue sur le microscope (en micromètres) servant à calculer
l’épaisseur de feuil est divisée par un diviseur attribué à l’outil d’entaille en coin.
La plage de mesure de l’épaisseur de feuil est:
— déterminée par l’angle de l’entaille en coin, les dimensions de l’outil d’entaille en coin et la plage de
mesure de l’échelle du microscope;
— limitée par la profondeur de champ du microscope de mesure (voir A.9).
La résolution du mesurage de l’épaisseur de feuil sec est déterminée par l’angle de l’entaille en coin et la
division d’échelle du microscope de mesure.
EXEMPLE Pour des angles courants d’entaille en coin α = 5,7° et α = 14,0°, les éléments suivants sont indiqués
dans le Tableau 1:
— le facteur d’entaille en coin tan α;
— la plage de mesure de l’épaisseur de feuil sec (= plage de mesure de l’échelle × tan α);
— la résolution absolue de l’épaisseur de feuil sec (= division d’échelle × tan α);
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— la résolution relative de l’épaisseur de feuil sec Δ (= (Δ /t ) × 100; t = épaisseur de feuil sec).
r a d d
Ci-dessus, il est supposé que le microscope de mesure a une plage de mesure d’échelle de 2 mm et une
division d’échelle de 0,02 mm et que l’outil d’entaille en coin est correctement dimensionné.
Tableau 1 — Données numériques concernant la méthode d’entaille en coin
Angle de l’entaille en coin α ° 5,7 14,0
Facteur d’entaille en coin tan α 0,10 0,25
Plage de mesure de l’épaisseur de feuil µm jusqu’à 200 jusqu’à 500
Résolution absolue de l’épaisseur de feuil Δ µm 2 5
a
Résolution relative de l’épaisseur de feuil Δ % 200/t 500/t
r d d
La Figure 2 représente une entaille en coin réalisée selon la méthode B dans la section transversale (I)
et l’image de l’entaille en coin associée (II) visible à travers le microscope. Ici, la section l à mesurer au
microscope est la distance entre les cercles concentriques.
Légende
1 section transversale
2 image de l’entaille en coin
I revêtement
II subjectile
l base de l’entaille en coin
t épaisseur de feuil sec
d
α angle de l’entaille en coin
Figure 2 — Entaille en coin selon la méthode B (une seule couche)
Dans le cas de systèmes de revêtement, les épaisseurs individuelles de feuil peuvent être déterminées
de manière similaire.
La Figure 3 représente la pointe d’entaille en coin (méthode A) pour un système bicouche. Les épaisseurs
individuelles de feuil sec t et t sont ensuite calculées à partir des valeurs lues sur le microscope l et
d1 d2 1
l avec la Formule (1) pour t = l · tan α et t = l · tan α.
2 d1 1 d2 2
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Légende
1 couche 1
2 couche 2
3 subjectile
l base de l’entaille en coin associée à t (i = 1, 2)
i di
t épaisseur de feuil sec de la couche i (i = 1, 2)
di
α angle de l’entaille en coin
Figure 3 — Entaille en coin selon la méthode A (système bicouche/section transversale)
6 Appareillage
6.1 Méthode A
6.1.1 Dispositif de rayage, comme illustré schématiquement à la Figure 4, présentant les
caractéristiques suivantes.
6.1.1.1 Le stylet 6 est fixé de manière interchangeable dans le bloc métallique 7 et il dépasse autant
que les boulons de soutien 3.
NOTE Il existe des dispositifs de rayage qui sont munis de roues de soutien à la place des boulons de soutien.
6.1.1.2 Le dispositif doit être réglé de manière que, lorsqu’il se trouve sur une surface plane, l’axe du
stylet 8 soit orienté à la verticale de cette surface.
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a) Vue latérale
b) Vue de face
Légende
1 direction de charge 5 subjectile
2 direction de rayage 6 stylet d’entaille en coin
3 boulons de soutien 7 bloc métallique
4 revêtement 8 axe du stylet
Figure 4 — Dispositif de rayage
6.1.2 Stylet d’entaille en coin, en métal dur et ayant une forme conforme à la Figure 5, avec indication
du facteur d’entaille en coin et/ou de l’angle de l’entaille en coin.
Légende
1 tige
2 bord tranchant
3 axe du stylet
α angle de l’entaille en coin
Figure 5 — Stylet d’entaille en coin
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6.2 Méthode B
6.2.1 Dispositif de perçage, comme illustré schématiquement à la Figure 6, présentant les
caractéristiques suivantes.
6.2.1.1 Le mouvement de rotation du foret 9 fixé de manière interchangeable dans la broche 4 (voir la
Figure 6) peut être produit manuellement ou par un entraînement électromoteur.
6.2.1.2 Le dispositif doit être réglé de manière que, lorsqu’il se trouve sur une surface plane, l’axe du
foret 2 soit orienté à la verticale de cette surface.
Légende
1 direction de charge 6 support
2 axe du foret 7 revêtement
3 mouvement de rotation 8 subjectile
4 broche avec mandrin 9 foret d’entaille en coin
5 guide de la broche 10 logement
Figure 6 — Dispositif de perçage
6.2.2 Foret d’entaille en coin, en métal dur et ayant une forme conforme à la Figure 7, avec indication
du facteur d’entaille en coin et/ou de l’angle de l’entaille en coin.
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Légende
1 accouplement 4 bord tranchant
2 tige 5 axe du foret
3 tête de perçage α angle de l’entaille en coin
Figure 7 — Foret d’entaille en coin
6.3 Microscope de mesure
Microscope de mesure et dispositif d’éclairage avec:
— un grossissement de 40x au minimum;
— une plage de mesure de 2 mm au minimum; et
— une division d’échelle de 0,02 mm au maximum.
NOTE 1 Les dispositifs standards d’entaille en coin sont munis d’un microscope de mesure et d’un dispositif
d’éclairage intégrés.
NOTE 2 Il est possible d’utiliser un microscope vidéo à la place d’un microscope de mesure conventionnel et
d’évaluer l’image de l’entaille en coin numériquement.
7 Éprouvettes
Les éprouvettes doivent présenter une surface plane mesurant au moins deux fois le plan de base du
dispositif d’entaille en coin.
NOTE 1 Il existe des dispositifs de serrage des dispositifs de perçage (méthode B) qui permettent également
de réaliser des mesurages sur des éprouvettes avec une très petite surface plane (généralement 15 mm × 15 mm).
Les éprouvettes de géométrie complexe (par exemple profilés) peuvent également être fixées avec ces dispositifs
pour mesurer leur épaisseur de feuil sec.
NOTE 2 Dans certaines conditions aux limites, les déterminations d’épaisseur de feuil sur des éprouvettes
incurvées sont également possibles (voir l’Annexe C).
8 Mode opératoire
8.1 Préparation de l’échantillon
Il convient de préférence d’appliquer un marquage de contraste laminaire sur le revêtement dans la
zone dans laquelle l’entaille en coin doit être réalisée, de manière à faciliter le mesurage au microscope.
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Un stylo feutre noir indélébile est normalement utilisé pour les revêtements clairs. Un stylo feutre blanc
ou argenté peut être utilisé pour les éprouvettes sombres. Dans ce cas, la couche de marquage doit être
mince et elle doit avoir complètement durci avant de réaliser l’entaille en coin. Il faut s’assurer que le
solvant contenu dans le stylo feutre n’attaque pas le revêtement.
8.2 Nombre de déterminations
Pour chaque détermination d’épaisseur de feuil sec, trois pointes ou forets d’entaille en coin doivent
respectivement être appliqués sur le panneau d’essai. La base de l’entaille en coin, l, doit être mesurée
en deux points d’essai différents pour chaque rayure ou chaque trou.
8.3 Méthode A (pointe d’entaille en coin)
8.3.1 Insérer le stylet d’entaille en coin (6.1.2) correspondant à la plage de mesure prévue selon 6.1.1.1
dans le dispositif de rayage (6.1.1) et le fixer.
8.3.2 Placer le dispositif de rayage sur le revêtement et le tirer à une vitesse d’environ 10 mm/s sur
une section de 10 mm au minimum (voir l’élément 2 à la Figure 4). Lors de cette opération, appuyer sur
le dispositif de rayage de manière à réaliser une rayure dans le subjectile.
8.3.3 Placer le microscope de mesure (6.3) sur le revêtement et mesurer la largeur de la projection
du flanc de l’entaille en coin de la surface (marquage) sur le subjectile (voir la Figure 1) dans le sens
transversal de la pointe d’entaille en coin, en deux points de la pointe.
8.3.4 Utiliser les valeurs mesurées et le facteur d’entaille en coin du stylet pour calculer les épaisseurs
de feuil sec, en micromètres, selon la Formule (1).
8.3.5 Répéter les étapes 8.3.2 à 8.3.4 en deux autres points de l’éprouvette.
8.3.6 Pour le résultat, indiquer la valeur moyenne, en micromètres, des six déterminations.
8.3.7 Pour déterminer les épaisseurs individuelles de feuil sec d’un système de revêtement, procéder
de la même manière et conformément à l’Article 5.
8.4 Méthode B (alésage d’entaille en coin)
8.4.1 Insérer le foret d’entaille en coin (6.2.2) correspondant à la plage de mesure prévue dans le
dispositif de perçage (6.2.1) et le fixer.
8.4.2 Placer le dispositif de perçage sur le revêtement et abaisser le foret en rotation sur le revêtement.
Lors de cette opération, charger la broche axialement (voir l’élément 1 à la Figure 6) de façon que le trou
percé à travers le revêtement jusqu’au subjectile soit conique.
8.4.3 Placer le microscope de mesure (6.3) sur le revêtement et mesurer la largeur de la projection du
flanc de l’entaille en coin de la surface (marquage) sur le subjectile (voir la Figure 2) dans le sens radial,
en deux points du cône de perçage.
8.4.4 Utiliser les valeurs mesurées et le facteur d’entaille en coin du foret pour calculer les épaisseurs
de feuil sec, en micromètres, selon la Formule (1).
8.4.5 Répéter les étapes 8.3.2 à 8.3.4 en deux autres points de l’éprouvette.
8.4.6 Pour le résultat, indiquer la valeur moyenne, en micromètres, des six déterminations.
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8.4.7 Pour déterminer les épaisseurs individuelles de feuil sec d’un système de revêtement, procéder
de la même manière et conformément à l’Article 5.
9 Fidélité
Aucune donnée de fidélité n’est disponible pour le moment.
10 Rapport d’essai
Le rapport d’essai doit comprendre au minimum les informations suivantes:
a) tous les détails nécessaires à l’identification et à la caractérisation de l’éprouvette, c’est-à-dire:
1) concernant le revêtement (fabricant, identification du produit, numéro de lot,
méthode d’application, conditions de séchage/durcissement, conditions de
vieillissement/conditionnement, etc.); et
2) concernant le subjectile (matériau, épaisseur, forme, dimensions, courbure, etc.);
b) une référence à la présente Norme internationale, à savoir l’ISO 19399;
c) la méthode utilisée (A ou B);
d) l’outil d’entaille en coin utilisé (facteur d’entaille en coin/angle de l’entaille en coin);
e) les résultats d’essai conformément à 8.3.6, 8.3.7, 8.4.6 ou 8.4.7: l’épaisseur de feuil sec et, le cas
échéant, les épaisseurs individuelles de feuil sec, en micromètres;
f) tout écart par rapport à la méthode d’essai spécifiée;
g) toute caractéristique inhabituelle (anomalies) observée pendant l’essai;
h) le nom de l’inspecteur et du laboratoire d’essai;
i) la date de l’essai.
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ISO 19399:2016(F)
Annexe A
(informative)
Sources d’erreur et problèmes de mesure
A.1 Revêtement mou et/ou élastique
A.1.1 Phénomène
Trois effets négatifs peuvent être observés si les revêtements sont trop mous et/ou trop élastiques:
— L’image de l’entaille en coin est altérée par des débris non séparés qui adhèrent au produit de
peinture entaillé (au moins un des repères de contraste n’est pas clairement distinct).
— L’angle effectif de l’entaille en coin est supérieur à l’angle nominal spécifié en raison du retour
élastique du revêtement après le rayage/perçage.
— Un renflement peut être causé par la déformation plastique du revêtement mou au niveau du bord
supérieur de l’entaille en coin.
A.1.2 Effet
Il est impossible de réaliser une évaluation correcte si les repères de contraste ne sont pas clairement
distincts et en cas de formation d’un renflement. L’épaisseur de feuil sec ne peut être estimée que de
manière approximative dans le meilleur des cas.
En cas de retour élastique du revêtement, des valeurs d’épaisseur de feuil sec trop faibles sont
systématiquement déterminées.
A.1.3 Solution
Dans certains cas, les propriétés mécaniques du revêtement peuvent être optimisées par refroidissement
(au congélateur ou par projection à froid). En cas de projection à froid, la surface du revêtement doit
être protégée contre l’attaque par les solvants avec une feuille d’aluminium.
Afin d’éviter la formation de débris non séparés du produit de peinture, il convient de toujours réaliser
le perçage par intermittence, c’est-à-dire pas en une passe, dans le cas de la méthode B. Éliminer les
débris entre les passes.
A.2 Subjectile mou et/ou élastique
A.2.1 Phénomène
Quatre effets négatifs peuvent être observés si les subjectiles sont trop mous et/ou trop élastiques:
— Le repère de contraste inférieur n’est pas clairement distinct en raison des débris de subjectile non
séparés qui adhèrent à l’entaille en coin.
— Les débris de subjectile longs peuvent causer un décollement de la couche si le matériau du subjectile
est résistant (voir A.4).
— Le retour élastique du subjectile après le rayage/perçage empêche de distinguer le repère de
contraste inférieur.
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— Un renflement peut être causé par la déformation plastique du subjectile mou au niveau du bord
supérieur du subjectile.
A.2.2 Effet
Il est impossible de réaliser une évaluation correcte si les repères de contraste ne sont pas clairement
distincts et en cas de formation d’un renflement. L’épaisseur de feuil sec ne peut être estimée que de
manière approximative dans le meilleur des cas.
A.2.3 Solution
Pour les subjectiles en plastique, les propriétés mécaniques peuvent être optimisées par refroidissement
(au congélateur ou par projection à froid) dans certains cas. En cas de projection à froid, la surface du
revêtement doit être protégée contre l’attaque par les solvants avec une feuille d’aluminium.
Afin d’éviter la formation de débris de subjectile non séparés, il convient de toujours réaliser le perçage
par intermittence, c’est-à-dire pas en une passe, et aussi profondément que possible dans le subjectile
dans le cas de la méthode B. Éliminer les débris entre les passes.
A.3 Subjectile dur (ne pouvant pas être rayé/percé)
A.3.1 Phénomène
Lorsque les matériaux des subjectiles sont très durs (par exemple béton), l’entaille en coin ne peut pas
être réalisée totalement (c’est-à-dire pas dans le subjectile) et le repère de contraste inférieur est donc
absent ou il est uniquement reconnaissable de manière indistincte sur l’image de l’entaille en coin.
A.3.2 Effet
L’entaille en coin ne peut pas être évaluée correctement. Seule une limite inférieure peut être indiquée
pour l’épaisseur de feuil sec dans le meilleur des cas.
A.3.3 Solution
Méthode A: Il n’existe aucune solution technique à ce problème de mesure.
Méthode B: La base de l’entaille en coin, l, peut être déterminée en mesurant le diamètre complet du
cône de perçage et en le divisant par deux. Si la plage de mesure de l’échelle du microscope n’est pas
adéquate, un foret avec un angle d’entaille en coin plus grand (mais également avec une résolution
d’épaisseur de feuil sec inférieure) doit être utilizé.
A.4 Entaille en coin avec un défaut d’adhérence
A.4.1 Phénomène
La partie inférieure du flanc de l’entaille en coin s’est rompue en raison d’un décollement. Ce décollement
est souvent causé par la formation de débris de subjectile longs dans le cas de matériaux de subjectile
qui sont trop résistants.
A.4.2 Effet
Les valeurs confirmées pour l’épaisseur de feuil sec sont systématiquement trop petites. Seule une
limite inférieure peut être indiquée pour l’épaisseur de feuil sec.
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A.4.3 Solution
L’effet de décollement est particulièrement drastique si l’outil d’entaille en coin pénètre dans la limite
entre le revêtement et le subjectile. Il convient donc de réaliser le rayage/perçage aussi profo
...
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