ASTM B571-97(2003)
(Practice)Standard Practice for Qualitative Adhesion Testing of Metallic Coatings
Standard Practice for Qualitative Adhesion Testing of Metallic Coatings
SCOPE
1.1 This practice describes simple, qualitative tests for evaluating the adhesion of metallic coatings on various substances.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:B571–97(Reapproved 2003)
Standard Practice for
Qualitative Adhesion Testing of Metallic Coatings
This standard is issued under the fixed designation B 571; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope one uses any means available to attempt to separate the coating
from the substrate. This may be prying, hammering, bending,
1.1 This practice describes simple, qualitative tests for
beating, heating, sawing, grinding, pulling, scribing, chiseling,
evaluating the adhesion of metallic coatings on various sub-
or a combination of such treatments. If the coating peels,
stances.
flakes, or lifts from the substrate, the adhesion is less than
1.2 This standard does not purport to address all of the
perfect.
safety concerns, if any, associated with its use. It is the
2.6 If evaluation of adhesion is required, it may be desirable
responsibility of the user of this standard to establish appro-
to use one or more of the following tests. These tests have
priate safety and health practices and determine the applica-
varying degrees of severity; and one might serve to distinguish
bility of regulatory limitations prior to use.
between satisfactory and unsatisfactory adhesion in a specific
2. Significance and Use
application. The choice for each situation must be determined.
2.7 When this guideline is used for acceptance inspection,
2.1 These tests are useful for production control and for
the method or methods to be used must be specified. Because
acceptance testing of products.
the results of tests in cases of marginal adhesion are subject to
2.2 Interpreting the results of qualitative methods for deter-
interpretation, agreement shall be reached on what is accept-
mining the adhesion of metallic coatings is often a controver-
able.
sial subject. If more than one test is used, failure to pass any
2.8 If the size and shape of the item to be tested precludes
one test is considered unsatisfactory. In many instances, the
use of the designated test, equivalent test panels may be
end use of the coated article or its method of fabrication will
appropriate. If permitted, test panels shall be of the same
suggest the technique that best represents functional require-
material and have the same surface finish as the item to be
ments. For example, an article that is to be subsequently
tested and shall be processed through the same preplating,
formed would suggest a draw or a bend test; an article that is
electroplating, and postplating cycle with the parts they repre-
to be soldered or otherwise exposed to heat would suggest a
sent.
heat-quench test. If a part requires baking or heat treating after
plating, adhesion tests should be carried out after such post-
3. Bend Tests
treatment as well.
3.1 Bend the part with the coated surface away over a
2.3 Several of the tests are limited to specific types of
mandrel until its two legs are parallel. The mandrel diameter
coatings, thickness ranges, ductilities, or compositions of the
should be four times the thickness of the sample. Examine the
substrate. These limitations are noted generally in the test
deformed area visually under low magnification, for example,
descriptions and are summarized in Table 1 for certain metallic
43, for peeling or flaking of the coating from the substrate,
coatings.
which is evidence of poor adhesion. If the coating fractures or
2.4 “Perfect” adhesion exists if the bonding between the
blisters, a sharp blade may be used to attempt to lift off the
coating and the substrate is greater than the cohesive strength
coating. With hard or brittle coatings, cracking usually occurs
of either. Such adhesion is usually obtained if good electro-
in the bend area. Such cracks may or may not propagate into
plating practices are followed.
the substrate. In either case, cracks are not indicative of poor
2.5 For many purposes, the adhesion test has the objective
adhesion unless the coating can be peeled back with a sharp
of detecting any adhesion less than “perfect.” For such a test,
instrument.
3.2 Bend the part repeatedly, back and forth, through an
These test methods are under the jurisdiction of ASTM Committee B08 on
angle of 180° until failure of the basis metal occurs. Examine
Metallic and Inorganic Coatings and are the direct responsibility of Subcommittee
the region at low magnification, for example, 103, for sepa-
B08.10 on Test Methods.
ration or peeling of the coating. Prying with a sharp blade will
Current edition approved May 10, 2003. Published July 2003. Originally
approved in 1979. Last previous edition approved in 1997 as B 571 – 97. indicate unsatisfactory adhesion by lift off of the coating.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
B571–97 (2003)
TABLE 1 Adhesion Tests Appropriate for Various Coatings
A
Coating Material
Lead and Tin and
Adhesion Test
Nickel and
Cadmium Chromium Copper Lead/Tin Nickel Palladium Rhodium Silver Tin/Lead Zinc Gold
Chromium
Alloy Alloy
Bend +−+++ + + + + + + +
Burnish −++−+ + − − + − + −
Chisel/knife +++++ − + − + + − +
Draw −−+−+ + − − − − + −
File −++++ + − + + + − +
Grind and ++−−+ + + − − + + −
saw
Heat/quench −++++ + − − + + − +
Impact +−+−+ + − − − − + −
Peel −++−+ − − − + + − +
Push −−−−+ + − − − − + −
Scribe −−+−+ − − − − − − −
A
+ Appropriate; − not appropriate.
TABLE 2 Temperature Test Guide
Coating Material
Chromium,
Lead, Gold and
Nickel, Nickel + Tin, Zinc, Palladium, Rhodium,
Substrate
Tin/Lead, Silver,
Chromium, Temperature, Temperature, Temperature, Temperature,
Temperature, Temperature,
Copper, °C °C °C °C
°C °C
Temperature, °C
Steel 250 150 150 150 250 350 185
Zinc alloys 150 150 150 150 150 150 150
Copper and 250 150 150 150 250 350 185
copper alloys
Aluminum and 220 150 150 150 220 220 185
aluminum alloys
4. Burnishing Test may be observed directly or evaluated further by techniques
described in Section 5 for detachment from the substrate. If
4.1 Rub a coated area of about 5 cm with a smooth-ended
there is peeling or flaking of the coating or if it can be
tool for approximately 15 s.Asuitable tool is a steel rod 6 mm
detached, the adhesion is not satisfactory.
in diameter with a smooth hemispherical end. The pressure
6.2 Results from this technique must be interpreted cau-
shall be sufficient to burnish the coating at each stroke but not
tiously, because the ductilities of both the coating and substrate
so great as to dig into it. Blisters, lifting, or peeling should not
are involved.
develop. Generally, thick deposits cannot be evaluated satis-
factorily.
7. File Test
7.1 Saw off a piece of the coated specimen and inspect it for
5. Chisel-Knife Test
detachmentatthedeposit/substrateinterface.Applycoarsemill
5.1 Use a sharp cold chisel to penetrate the coating on the
file across the sawed edge from the substrate toward the
article being evaluated. Alternatively the chisel may be placed
coating so as to raise it, using an approach angle of approxi-
in back of an overhang area of the coating or at a coating-
mately45°tothecoatingsurface.Liftingorpeelingisevidence
substrate interface exposed by sectioning the article with a saw.
of unsatisfactory adhesion.
A knife may be substituted for the chisel with or without
7.2 This technique is not suitable for thin or soft coatings.
hammering or light tapping. If it is possible to remove the
deposit, the adhesion i
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