ISO 17925:2004

Zinc and/or aluminium based coatings on steel - Determination of coating mass per unit area and chemical composition - Gravimetry, inductively coupled plasma atomic emission spectrometry and flame atomic absorption spectrometry

ISO 17925:2004 specifies methods of determining the coating mass per unit area by gravimetry and chemical composition on one side-surface of zinc- and/or aluminium-based coatings on steel by means of inductively coupled plasma atomic emission spectrometric or flame atomic absorption spectrometry. This method is applicable to zinc contents between 40 % (mass fraction) and 100 % (mass fraction); aluminium contents between 0,02 % (mass fraction) and 60 % (mass fraction); nickel contents between 7 % (mass fraction) and 20 % (mass fraction); iron contents between 0,2 % (mass fraction) and 20 % (mass fraction); silicon contents between 0,2 % (mass fraction) and 10 % (mass fraction); lead contents between 0,005 % (mass fraction) and 2 % (mass fraction). These test methods are intended as referee methods to test such materials for compliance with mass per unit area and compositional specifications of International Standards.

Revêtements à base de zinc et/ou d'aluminium sur acier — Détermination de la masse surfacique et de la composition chimique du revêtement — Gravimétrie, spectrométrie d'émission atomique avec plasma induit par haute fréquence et spectrométrie d'absorption atomique dans la flamme

General Information

• Status: Published
• Publication Date: 28-Oct-2004
• ICS: 25.220.40 - Metallic coatings
• ICS: 77.080.20 - Steels
• Technical Committee: ISO/TC 17/SC 1 - Methods of determination of chemical composition
• Drafting Committee: ISO/TC 17/SC 1 - Methods of determination of chemical composition
• Current Stage: 9093 - International Standard confirmed
• Start Date: 21-Aug-2024
• Completion Date: 13-Dec-2025

Overview

ISO 17925:2004 specifies laboratory methods for measuring the mass per unit area and chemical composition of zinc- and/or aluminium-based coatings on steel. It defines a referee procedure that combines gravimetry (mass loss after stripping) with spectrometric techniques - inductively coupled plasma atomic emission spectrometry (ICP‑AES) and flame atomic absorption spectrometry (FAAS) - to determine coating mass and elemental composition on one side of a coated steel specimen.

Key elements, applicable ranges and limits are defined (examples):

• Zinc: 40 % to 100 % (mass fraction)
• Aluminium: 0.02 % to 60 %
• Nickel: 7 % to 20 %
• Iron: 0.2 % to 20 %
• Silicon: 0.2 % to 10 %
• Lead: 0.005 % to 2 %
  Note: FAAS is not applicable for zinc determination per the standard.

Key topics and technical requirements

• Principle: Stripping the coating from one side using an HCl-based stripping solution with an inhibitor (hexamethylenetetramine) to protect the base steel; determine coating mass from the specimen mass difference divided by surface area.
• Chemical analysis: Dilution, filtration and analysis of the stripped solution by ICP‑AES or FAAS to calculate element contents relative to coating mass.
• Reagents and standards: Detailed preparation of acids, stripping solutions and traceable stock/working standard solutions for Zn, Al, Ni, Fe, Si, Pb (concentrations and preparation instructions are specified).
• Apparatus & spectral data: Requirements for ICP‑AES and FAAS instrumentation and example analytical lines and interferences (wavelengths and interference notes).
• Sampling & sample prep: Guidance for protecting one side (stop-off materials or mechanical fixtures) and preventing contamination during stripping.
• Precision & reporting: Expression of results in mass per unit area and compositional mass fractions; intended as referee methods for compliance testing to international specifications.

Practical applications and users

ISO 17925 is used by:

• Independent testing laboratories performing referee or compliance tests.
• Coating and galvanizing manufacturers (hot-dip, electrolytic, zinc‑nickel, zinc‑Al alloys) for certification and quality control.
• Procurement and inspection bodies verifying supplier claims for coating mass and alloy composition.
• Standards committees and R&D teams developing coating specifications or validating analytical procedures.

Common applications include verifying galvanized steel, galvaneal, zinc‑nickel and zinc‑aluminium coatings for corrosion protection and contractual compliance.

Related standards

Normative references include ISO 648, ISO 1042, ISO 3696 (water quality), ISO 5725‑1/2/3 (accuracy and precision), and ISO 14284 (sampling and sample preparation).

Keywords: ISO 17925, zinc coatings, aluminium coatings, coating mass per unit area, gravimetry, ICP‑AES, FAAS, coating composition analysis, galvanized steel.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 17925
First edition
2004-11-01
Zinc and/or aluminium based coatings on
steel — Determination of coating mass
per unit area and chemical
composition — Gravimetry, inductively
coupled plasma atomic emission
spectrometry and flame atomic
absorption spectrometry
Revêtements à base de zinc et/ou d'aluminium sur acier —
Détermination de la masse surfacique et de la composition chimique du
revêtement — Gravimétrie, spectrométrie d'émission atomique avec
plasma induit par haute fréquence et spectrométrie d'absorption
atomique dans la flamme
Reference number
©
ISO 2004
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ii © ISO 2004 – All rights reserved

Contents Page
Foreword. iv
1 Scope. 1
2 Normative references . 1
3 Principle . 2
4 Reagents . 2
5 Apparatus. 5
5.1 General. 5
5.2 Inductively coupled plasma atomic emission spectrometer (ICP-AES). 5
5.3 Flame atomic absorption spectrometer (FAAS) . 6
5.4 Platinum crucible . 7
6 Sampling and samples . 7
7 Determination procedure . 7
7.1 Sample preparation. 7
7.2 Determination procedure for mass per unit area . 7
7.3 Procedure of determination of chemical composition by inductively coupled plasma
atomic emission spectrometric method. 8
7.4 Procedure of determination of chemical composition by flame atomic absorption method
— zinc, aluminium, nickel and iron contents. 14
8 Expression of results. 14
8.1 Expression of result in mass per unit area .14
8.2 Expression of result of chemical compositions . 15
9 Test report. 17
Annex A (informative) Analyte content . 18
Annex B (informative) Additional information on the international cooperative tests. 19
Annex C (informative) Graphical representation of precision data. 22

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 17925 was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 1, Methods of
determination of chemical composition.

iv © ISO 2004 – All rights reserved

INTERNATIONAL STANDARD ISO 17925:2004(E)

Zinc and/or aluminium based coatings on steel —
Determination of coating mass per unit area and chemical
composition — Gravimetry, inductively coupled plasma atomic
emission spectrometry and flame atomic absorption
spectrometry
1 Scope
This International Standard specifies methods of determining the coating mass per unit area by gravimetry
and chemical composition on one side-surface of zinc- and/or aluminium-based coatings on steel by means of
inductively coupled plasma atomic emission spectrometric or flame atomic absorption spectrometry. For
example, this test method applies for zinc and/or aluminium based coatings on steel such as galvanize (hot
dip and electrolytic), galvaneal (hot-dip), zinc-nickel electrolytic, zinc-5 % aluminium coating (hot-dip) and zinc-
55 % aluminium coating (hot-dip). Galvanizing gives a pure zinc coating. Galvanealling gives a zinc-iron
alloyed coating. Zinc-nickel electrolytic methods give zinc-nickel alloyed coatings.
This method is applicable to zinc contents between 40 % (mass fraction) and 100 % (mass fraction);
aluminium contents between 0,02 % (mass fraction) and 60 % (mass fraction); nickel contents between 7 %
(mass fraction) and 20 % (mass fraction); iron contents between 0,2 % (mass fraction) and 20 % (mass
fraction); silicon contents between 0,2 % (mass fraction) and 10 % (mass fraction); lead contents between
0,005 % (mass fraction) and 2 % (mass fraction). For example, the applicable elements for these products are
as follows: galvanizing is specified for iron and aluminium; galvanealling is specified for zinc, iron and
aluminium; zinc-nickel electrolytic methods are specified for zinc, iron and nickel; zinc-5 % aluminium coating
is specified for zinc, iron, aluminium and silicon; zinc-55 % aluminium is specified for zinc, iron, aluminium and
silicon.
FAAS determination for the chemical composition of a coating layer is not applicable for zinc.
These test methods are intended as referee methods to test such materials for compliance with mass per unit
area and compositional specifications of International Standards.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 648:1977, Laboratory glassware — One-mark pipettes
ISO 1042:1998, Laboratory glassware — One-mark volumetric flasks
ISO 3696:1987, Water for analytical laboratory use — Specification and test methods
ISO 5725-1:1994, Accuracy (trueness and precision) of measurement methods and results — Part 1: General
principles and definitions
ISO 5725-2:1994, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic
method for the determination of repeatability and reproducibility of a standard measurement method
ISO 5725-3:1994, Accuracy (trueness and precision) of measurement methods and results — Part 3:
Intermediate measures of the precision of a standard measurement method
ISO 14284:1996, Steel and iron — Sampling and preparation of samples for the determination of chemical
composition
3 Principle
Stripping the coating on one side on the base steel in a mixture of hydrochloric acid solution containing an
inhibitor to prevent the attack on the base steel. Determination of the mass per unit area of coating from the
mass difference of the specimen before and after stripping. Calculating the coating mass as the mass
difference divided by the specimen's surface area.
Dilution of the stripped solution of the coating on one side. Filtration and nebulization of the solution into an
inductively coupled plasma atomic emission spectrometer (ICP-AES) or flame atomic absorption spectrometer
(FAAS). Calculating the chemical compositions of coating layer as the content of the analytical element
divided by the pre-measured coating mass.
Examples of the analytical lines are given in Table 1.
Table 1 — Examples of analytical lines together with interfering elements
ICP-AES FAAS
Analytical line Analytical line
Element
Interfering Interfering
elements elements
nm nm
481,0
Zinc
206,19
309,3
Aluminium 396,15
306,16
232,00
Nickel 231,60 231,10
233,75
271,44 248,33
Iron
259,94 252,29
251,61 251,61
Silicon Aluminium Aluminium
288,16 288,16
Zinc 217,00
Lead 220,35
Aluminium 283,31
4 Reagents
During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only
grade 2 water as specified in ISO 3696.
4.1 Hydrochloric acid, HCl, ρ ≈ 1,18 g/ml.
4.2 Hydrochloric acid, HCl, diluted 1+10.
4.3 Nitric acid, HNO , ρ ≈ 1,40 g/lml.
2 © ISO 2004 – All rights reserved

4.4 Nitric acid, HNO , diluted 1+1.
4.5 Mixed acid, prepared by adding 50 ml of nitric acid (4.3) and 10 ml of hydrochloric acid (4.1) to a flask
containing 150 ml of water and mixing.
4.6 Sodium carbonate, Na CO .
2 3
4.7 Hexamethylenetetramine, C H N , capable of preventing acid attack of the base metal while
6 12 4
stripping the coating from the base steel.
4.8 Stripping solution, prepared by transferring from 170 ml to 500 ml of hydrochloric acid (4.1) to a 1 l
graduated cylinder containing from 450 ml to 820 ml of water and adding 3,5 g of hexamethylenetetramine
(4.7) then diluting to the mark with water followed by mixing.
NOTE For an electrolytic zinc coated steel such as one with a lower coating mass, it would be better to use diluted
hydrochloric acid for stripping in order to prevent the dissolution of base steel.
4.9 Stop-off materials, capable of protecting one side of a coated piece of steel sheet while the other side
is being stripped in hydrochloric acid solution, without contaminating the acid solution and either gaining or
losing mass thus avoiding interference with coating mass and chemical composition determination.
NOTE 1 Acid-resistant paints, lacquers or acid-resistant tapes are commonly used as stop-off materials.
NOTE 2 For this purpose mechanical devices may also be used, fastened to the test specimen instead of the above
materials.
4.10 Zinc stock standard solution, 1 000 mg/l, prepared as follows:
weigh, to the nearest 0,000 5 g, 0,5 g of high purity zinc (minimum 99,99 % by mass) and dissolve in 25 ml
hydrochloric acid (4.1). Cool and transfer the solution quantitatively to a calibrated 500 ml one-mark volumetric
flask. Keep the flask at the same temperature as that at which the flask was calibrated. Dilute to the mark with
water and mix.
4.11 Zinc standard solution A, 100 mg/l, prepared as follows:
using a calibrated pipette, transfer 100 ml of the zinc stock standard solution (4.10) into a calibrated 1 000 ml
one-mark volumetric flask. Add 10 ml of hydrochloric acid (4.1). Dilute to the mark with water and mix.
4.12 Zinc standard solution B, 10 mg/l, prepared as follows:
using a calibrated pipette, transfer 100 ml of the zinc standard solution A (4.11) into a calibrated 1 000 ml one-
mark volumetric flask. Add 10 ml of hydrochloric acid (4.1). Dilute to the mark with water and mix.
4.13 Zinc standard solution for matrix matching, 10 000 mg/l, prepared as follows:
weigh, to the nearest 0,01 g, 10 g of high purity zinc (minimum 99,99 % by mass) and dissolve in 200 ml
hydrochloric acid (4.1), Cool and transfer the solution quantitatively to a calibrated 1 000 ml one-mark
volumetric flask. Keep the flask at the same temperature as that at which the flask was calibrated. Dilute to the
mark with water and mix.
4.14 Aluminium stock standard solution, 1 000 mg/l, prepared as follows:
weigh, to the nearest 0,000 5 g, 0,5 g of high purity aluminium (minimum 99,95 % by mass) and dissolve in a
mixture of 25 ml hydrochloric acid (4.1) and 5 ml nitric acid (4.3). Cool and transfer the solution quantitatively
to a calibrated 500 ml one-mark volumetric flask. Keep the flask at the same temperature as that at which the
flask was calibrated. Dilute to the mark with water and mix.
4.15 Aluminium standard solution A, 100 mg/l, prepared as follows:
using a calibrated pipette, transfer 100 ml of the aluminium stock standard solution (4.14) into a calibrated
1 000 ml one-mark volumetric flask. Add 10 ml of hydrochloric acid (4.1). Dilute to the mark with water and mix.
4.16 Aluminium standard solution B, 10 mg/l, prepared as follows:
using a calibrated pipette, transfer 100 ml of the aluminium standard solution A (4.15) into a calibrated
1 000 ml one-mark volumetric flask. Add 10 ml of hydrochloric acid (4.1). Dilute to the mark with water and mix.
4.17 Aluminium standard solution for matrix matching, 10 000 mg/l, prepared as follows:
weigh, to the nearest 0,01 g, 10 g of high purity aluminium (minimum 99,99 % by mass) and dissolve in a
mixture of 200 ml hydrochloric acid (4.1) and 5 ml nitric acid (4.3). Cool and transfer the solution quantitatively
to a calibrated 1 000 ml one-mark volumetric flask. Keep the flask at the same temperature as that at which
the flask was calibrated. Dilute to the mark with water and mix.
4.18 Nickel stock standard solution, 1 000 mg/l, prepared as follows:
weigh, to the nearest 0,000 5 g, 0,5 g of high purity nickel (minimum 99,95 % by mass) and dissolve in 30 ml
nitric acid (1+1) (4.4). Cool and transfer the solution quantitatively to a calibrated 500 ml one-mark volumetric
flask. Keep the flask at the same temperature as that at which the flask was calibrated. Dilute to the mark with
water and mix.
4.19 Nickel standard solution A, 100 mg/l, prepared as follows:
using a calibrated pipette, transfer 100 ml of the nickel stock standard solution (4.18) into a calibrated
1 000 ml one-mark volumetric flask. Add 10 ml of hydrochloric acid (4.1). Dilute to the mark with water and mix.
4.20 Nickel standard solution B, 10 mg/l, prepared as follows:
using a calibrated pipette, transfer 100 ml of the nickel standard solution A (4.19) into a calibrated 1 000 ml
one-mark volumetric flask. Add 10 ml of hydrochloric acid (4.1). Dilute to the mark with water and mix.
4.21 Iron stock standard solution, 1 000 mg/l, prepared as follows:
weigh, to the nearest 0,000 5 g, 0,5 g of high purity iron (minimum 99,95 % by mass) and dissolve in 25 ml
hydrochloric acid (4.1). Cool and transfer the solution quantitatively to a calibrated 500 ml one-mark volumetric
flask. Keep the flask at the same temperature as that at which the flask was calibrated. Dilute to the mark with
water and mix.
4.22 Iron standard solution A, 100 mg/l, prepared as follows:
using a calibrated pipette, transfer 100 ml of the iron stock standard solution (4.21) into a calibrated 1 000 ml
one-mark volumetric flask. Add 10 ml of hydrochloric acid (4.1). Dilute to the mark with water and mix.
4.23 Iron standard solution B, 10 mg/l, prepared as follows:
using a calibrated pipette, transfer 100 ml of the iron standard solution A (4.22) into a calibrated 1 000 ml one-
mark volumetric flask. Add 10 ml of hydrochloric acid (4.1). Dilute to the mark with water and mix.
4.24 Silicon stock standard solution, 1 000 mg/l, prepared as follows:
weigh, to the nearest 0,000 1 g, 2,139 3 g of freshly calcined high purity silica (minimum 99,9 % by mass
SiO ) and transfer to a platinum crucible. The high-purity silica shall be calcined for 1 h at 1 100°C and cooled
in a desiccator immediately before use. Mix thoroughly with 16 g of anhydrous sodium carbonate and fuse at
1 050°C for 30 min. Extract the fusion product with 100 ml of water in a polypropylene or
polytetrafluoroethylene beaker (see Note below). Cool and transfer the extract, which should contain no trace
of residue, to a 1 000 ml one-mark volumetric flask. Keep the flask at the same temperature as that at which
4 © ISO 2004 – All rights reserved

the flask was calibrated. Dilute to the mark and mix, transfer immediately to a well-stoppered
polytetrafluoroethylene bottle for storage. 1 ml of this stock solution contains 1 mg of silicon.
NOTE Extraction of the fusion product may require prolonged digestion in water followed by gentle heating.
4.25 Silicon standard solution A, 100 mg/l, prepared as follows:
using a calibrated pipette, transfer 100 ml of the silicon stock standard solution (4.24) into a calibrated
1 000 ml one-mark volumetric flask. Dilute to the mark with water and mix.
4.26 Silicon standard solution B, 10 mg/l, prepared as follows:
using a calibrated pipette, transfer 100 ml of the silicon standard solution A (4.25) into a calibrated 1 000 ml
one-mark volumetric flask. Dilute to the mark with water and mix.
4.27 Lead stock standard solution, 1 000 mg/l, prepared as follows:
weigh, to the nearest 0,000 5 g, 0,5 g of high purity lead (min 99,95 % by mass) and dissolve in 30 ml nitric
acid (1+1) (4.3). Cool and transfer the solution quantitatively to a calibrated 500 ml one-mark volumetric flask.
Keep the flask at the same temperature as that at which the flask was calibrated. Dilute to the mark with water
and mix.
4.28 Lead standard solution A, 100 mg/l, prepared as follows:
using a calibrated pipette, transfer 100 ml of the lead stock standard solution (4.27) into a calibrated 1 000 ml
one-mark volumetric flask. Dilute to the mark with water and mix.
4.29 Lead standard solution B, 10 mg/l, prepared as follows:
using a calibrated pipette, transfer 100 ml of the lead stock standard solution (4.28) into a calibrated 1 000 ml
one-mark volumetric flask. Dilute to the mark with water and mix.
4.30 Suitable solvent, appropriate for washing greasy or dirty test samples, e.g., acetone.
5 Apparatus
5.1 General
All volumetric glassware shall be class A and calibrated, in accordance with ISO 648 or ISO 1042 as
appropriate.
Use ordinary laboratory apparatus other than volumetric glassware.
5.2 Inductively coupled plasma atomic emission spectrometer (ICP-AES)
5.2.1 General
The ICP-AES used shall be satisfactory only after optimizing according to the manufacture's instructions.
The spectrometer can be either the simultaneous or the sequential type. If a sequential spectrometer can be
equipped with an extra arrangement for simultaneous measurement of the internal standard line, it can be
used with the internal reference technique. If the sequential spectrometer is not equipped with this
arrangement, an internal reference technique shall not be used.
5.2.2 Practical resolution of the spectrometer
Calculate the bandwidth (full width at half maximum) for the analytical line used including the line for internal
reference. The bandwidth shall be less than 0,030 nm.
5.2.3 Short-term stability
Calculate the standard deviation of ten measurements of the absolute intensity or intensity ratio of the emitted
light of the most concentrated calibration solution for analyte. The relative standard deviation shall not exceed
0,4 %.
5.2.4 Background equivalent concentration and detection limit
Calculate the background equivalent concentration (BEC) and detection limit (DL), for the analytical line in a
solution containing only the analyte element. The values of BEC and DL shall be below the value listed in
Table 2.
Table 2 — Background equivalent concentration, detection limit and characteristic mass
Inductively coupled atomic emission spectrometry
Background equivalent Detection limit
Element
concentration
mg/l mg/l
Zinc 1,0 0,4
Aluminium 6,0 0,2
Iron 2,0 0,1
Silicon 3,0 0,1
Lead 2,5 0,1
5.3 Flame atomic absorption spectrometer (FAAS)
5.3.1 General
The FAAS used will be satisfactory only after optimizing according to the manufacturer's instructions.
5.3.2 Short-term stability
The standard deviation of ten measurements of the absorbance of the most concentrated calibration solution
shall not exceed 1,5 % of the mean absorbance of the same solution.
The standard deviation of ten measurements of the absorbance of the least concentrated calibration solution
shall not exceed 0,5 % of the mean absorbance of the same solution.
5.3.3 Detection limit
Calculate the detection limit (DL) for the analytical line in a solution containing only the analyte element. This
is defined as three times the standard deviation of ten measurements of the absorbance of a solution
containing the appropriate element at a concentration level selected to give an absorbance just above that of
the zero member.
6 © ISO 2004 – All rights reserved

5.3.4 Calibration graph linearity
The slope of the calibration graph covering the top 20 % of concentration range (expressed as a change in
absorbance) shall not be less than 0,7 times the value of the slope for the bottom 20 % of the concentration
range determined in the same way. For instruments with automatic calibration using two or more standards, it
shall be established prior to the analysis, by obtaining absorbance readings, that the above requirements for
graph linearity are fulfilled.
5.3.5 Characteristics concentration
Calculate the characteristics concentration for the analyte in a matrix similar to the final test solution.
5.4 Platinum crucible
6 Sampling and samples
Sampling of test specimens for determining mass per unit area and chemical compositions of coating shall be
carried out in accordance with ISO 14284 and products standards, if specified. Test specimens shall be of

2 2
square, rectangular or round shape with a surface area of preferably 1 900 mm to 3 500 mm . In case of
dispute, test specimens shall be squares with sides of 50 mm ± 5 mm. One test specimen is required for each
side to be determined.
7 Determination procedure
7.1 Sample preparation
Clean the specimens with suitable solvent (4.30) using a soft paper towel, then dry with oil-free compressed
air.
Cover the side of the specimen from which the coating is not to be stripped with stop-off materials (4.9).
Use a roller, in the case of tape, to press the tape firmly against the sheet, making sure to remove all air
bubbles or wrinkles. Trim off the excess tape.
Preferably protect the edges with stop-off materials (4.9).
7.2 Determination procedure for mass per unit area
Using a calliper traceable to national or International Standards, measure the size of sample to be stripped to
the nearest 0,05 mm and calculate the area of the sample to the nearest 0,1 mm .
The area of the square test specimens shall be calculated as (a + b) × d/2 when the test specimen is not really
square and where d is the length of a diagonal line, and a and b are lengths of vertical lines from the corners
to the diagonal line (see Figure 1). Dimensions a, b and d shall be measured to the nearest 0,05 mm using a
device traceable to national or International Standards.
When the test specimen is not really square, if all corner angles are within a 4° deviation from 90°, the area of
the square and rectangle test specimens may be calculated as [(A + B) × (C + D)]/4, where A and B, C and D
are lengths of opposite sides as shown in Figure 1.
Figure 1 — Dimensions of square test specimens
Using a balance traceable to national or International Standards, weigh the prepared specimen to the nearest
0,1 mg and record the weight as the original weight of the specimen.
Place the sample in a sufficiently large beaker, e.g., 600 ml, with the
...