ASTM B571-2018 Standard Practice for Qualitative Adhesion Testing of Metallic Coatings.pdf

《ASTM B571-2018 Standard Practice for Qualitative Adhesion Testing of Metallic Coatings.pdf》由会员分享，可在线阅读，更多相关《ASTM B571-2018 Standard Practice for Qualitative Adhesion Testing of Metallic Coatings.pdf（4页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: B571 18Standard Practice forQualitative Adhesion Testing of Metallic Coatings1This standard is issued under the fixed designation B571; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe

2、r in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This practice covers simple, qualitative tests for eva

3、lu-ating the adhesion of metallic coatings on various substances.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is

4、 theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on sta

5、ndard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Significance and Use2.1 These tests are useful for production control and foraccepta

6、nce testing of products.2.2 Interpreting the results of qualitative methods for deter-mining the adhesion of metallic coatings is often a controver-sial subject. If more than one test is used, failure to pass anyone test is considered unsatisfactory. In many instances, theend use of the coated artic

7、le or its method of fabrication willsuggest the technique that best represents functional require-ments. For example, an article that is to be subsequentlyformed would suggest a draw or a bend test; an article that isto be soldered or otherwise exposed to heat would suggest aheat-quench test. If a p

8、art requires baking or heat treating afterplating, adhesion tests should be carried out after such post-treatment as well.2.3 Several of the tests are limited to specific types ofcoatings, thickness ranges, ductilities, or compositions of thesubstrate. These limitations are noted generally in the te

9、stdescriptions and are summarized in Table 1 for certain metalliccoatings.2.4 “Perfect” adhesion exists if the bonding between thecoating and the substrate is greater than the cohesive strengthof either. Such adhesion is usually obtained if good electro-plating practices are followed.2.5 For many pu

10、rposes, the adhesion test has the objectiveof detecting any adhesion less than “perfect.” For such a test,one uses any means available to attempt to separate the coatingfrom the substrate. This may be prying, hammering, bending,beating, heating, sawing, grinding, pulling, scribing, chiseling,or a co

11、mbination of such treatments. If the coating peels,flakes, or lifts from the substrate, the adhesion is less thanperfect.2.6 If evaluation of adhesion is required, it may be desirableto use one or more of the following tests. These tests havevarying degrees of severity; and one might serve to distin

12、guishbetween satisfactory and unsatisfactory adhesion in a specificapplication. The choice for each situation must be determined.2.7 When this guideline is used for acceptance inspection,the method or methods to be used must be specified. Becausethe results of tests in cases of marginal adhesion are

13、 subject tointerpretation, agreement shall be reached on what is accept-able.2.8 If the size and shape of the item to be tested precludesuse of the designated test, equivalent test panels may beappropriate. If permitted, test panels shall be of the samematerial and have the same surface finish as th

14、e item to betested and shall be processed through the same preplating,electroplating, and postplating cycle with the parts they repre-sent.3. Bend Tests3.1 Bend the part with the coated surface away over amandrel until its two legs are parallel. The mandrel diametershould be four times the thickness

15、 of the sample. Examine thedeformed area visually under low magnification, for example,4, for peeling or flaking of the coating from the substrate,which is evidence of poor adhesion. If the coating fractures orblisters, a sharp blade may be used to attempt to lift off the1This practice is under the

16、jurisdiction of ASTM Committee B08 on Metallicand Inorganic Coatings and is the direct responsibility of Subcommittee B08.10 onTest Methods.Current edition approved Aug. 1, 2018. Published August 2018. Originallyapproved in 1979. Last previous edition approved in 2013 as B571 97 (2013).DOI: 10.1520/

17、B0571-18.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment

18、 of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1coating. With hard or brittle coatings, cracking usually occursin the bend area. Such cracks may or may not propagate intothe substrate. In either case, cracks

19、are not indicative of pooradhesion unless the coating can be peeled back with a sharpinstrument.3.2 Bend the part repeatedly, back and forth, through anangle of 180 until failure of the basis metal occurs. Examinethe region at low magnification, for example, 10, for separa-tion or peeling of the coa

20、ting. Prying with a sharp blade willindicate unsatisfactory adhesion by lift off of the coating.4. Burnishing Test4.1 Rub a coated area of about 5 cm with a smooth-endedtool for approximately 15 s. A suitable tool is a steel rod 6 mmin diameter with a smooth hemispherical end. The pressureshall be s

21、ufficient to burnish the coating at each stroke but notso great as to dig into it. Blisters, lifting, or peeling should notdevelop. Generally, thick deposits cannot be evaluated satis-factorily.5. Chisel-Knife Test5.1 Use a sharp cold chisel to penetrate the coating on thearticle being evaluated. Al

22、ternatively the chisel may be placedin back of an overhang area of the coating or at a coating-substrate interface exposed by sectioning the article with a saw.A knife may be substituted for the chisel with or withouthammering or light tapping. If it is possible to remove thedeposit, the adhesion is

23、 not satisfactory. Soft or thin coatingscannot be evaluated for adhesion by this method.6. Draw Test6.1 Form a suitable sample about 60 mm in diameter into aflanged cap approximately 38 mm in diameter, to a depth up to18 mm, through the use of a set of adjustable dies in anordinary punch press.2Pene

24、tration of the male die may becontinued until the cap fractures. The adhesion of the coatingmay be observed directly or evaluated further by techniquesdescribed in Section 5 for detachment from the substrate. Ifthere is peeling or flaking of the coating or if it can bedetached, the adhesion is not s

25、atisfactory.6.2 Results from this technique must be interpretedcautiously, because the ductilities of both the coating andsubstrate are involved.7. File Test7.1 Saw off a piece of the coated specimen and inspect it fordetachment at the deposit/substrate interface.Apply coarse millfile across the saw

26、ed edge from the substrate toward thecoating so as to raise it, using an approach angle of approxi-mately 45 to the coating surface. Lifting or peeling is evidenceof unsatisfactory adhesion.7.2 This technique is not suitable for thin or soft coatings.2Romanoff, F. P., Transactions, Electrochem. Soc.

27、, Vol 65, 1934, p. 385;Proceedings, Amer. Electroplaters Soc. Vol 22, 1934, p. 155; Monthly Review,Amer. Electroplaters Soc., Vol 22, April 1935, p. 8.TABLE 1 Adhesion Tests Appropriate for Various CoatingsAdhesion TestCoating MaterialACadmium Chromium CopperLead andLead/TinAlloyNickelNickel andChro

28、miumPalladium Rhodium SilverTin andTin/LeadAlloyZinc andZinc AlloysGoldBend +Burnish + Chel/knife+ +Draw +File + +Grind andsaw+ +Heat/quench +Impact + Peel +Push + +Scribe + A+ Appropriate; not appropriate.TABLE 2 Temperature Test GuideSubstrateCoating MaterialChromium,Nickel, Nickel +Chromium,Coppe

29、r,Temperature, CTin,Temperature,CLead,Tin/Lead,Temperature,CZinc,and Zinc AlloysTemperature,CGold andSilver,Temperature,CPalladium,Temperature,CRhodium,Temperature,CSteel 250 150 150 150 250 350 185Zinc alloys 150 150 150 150 150 150 150Copper andcopper alloys250 150 150 150 250 350 185Aluminum anda

30、luminum alloys220 150 150 150 220 220 185B571 1828. Grind-Saw Test8.1 Hold the coated article against a rough emery wheel sothat the wheel cuts from substrate toward the deposit in a jerkyor bumpy fashion. A hack saw may be substituted for thewheel, making sure to saw in the direction that tends tos

31、eparate the coating from the substrate. Lifting or peeling isevidence of unsatisfactory adhesion.8.2 This technique is especially effective on hard or brittlecoatings but is not suitable for thin or soft coatings.9. Heat-Quench Test9.1 Heat the coated article in an oven for a sufficient timefor the

32、core of the part to reach the temperature shown in Table2. Maintain the temperature of the oven within 10C of thenominal. Coatings and substrates that are sensitive to oxidationshould be heated in an inert or reducing atmosphere or asuitable liquid. Then quench the part in water or other suitableliq

33、uid at room temperature.9.2 Flaking or peeling of the deposit is evidence of unsat-isfactory adhesion. Blisters may erupt during the heat andquench test when plating solution is entrapped in substratesurface pits or pores which are bridged by the deposit. If thedeposited coating cannot be peeled or

34、lifted from the substratein an area adjacent to the blister(s), the appearance of blistersshould not be interpreted as evidence of inferior adhesion.9.3 Diffusion and subsequent alloying of metals may im-prove the bond strength of electrodeposits. In some cases, abrittle layer may be created by the

35、materials involved causingpeeling as a result of fracture rather than poor adhesion. Thiswould not give a correct indication of the as-plated bondstrength.9.4 This test is nondestructive if the procedure does notcreate unwanted effects on parts.10. Impact Test10.1 Use a hammer or impact device coupl

36、ed with a suitablebacking block to support the article to be tested to deform thesample. Reproducible results are more easily obtained by theuse of a suitably modified impact tester where the force isreproducible and the impact head contour is in the form of a5-mm diameter ball, shock loaded by a fa

37、lling weight orswinging pendulum weight. The severity of the test may bealtered by changing the load and diameter of the ball. Exfolia-tion or blisters in and around indentations are evidence ofinadequate adhesion.10.2 This test is sometimes difficult to interpret. Soft andductile coatings are gener

38、ally not suited for evaluation.11. Peel Test11.1 Bond a strip of steel or brass about 1.5 mm thick and20 mm wide by solder or suitable adhesive to a properly flatarea of the coated surface of the article. Adhesive-backed tapemay be considered as a possible alternative. Heat curing of theadhesive may

39、 be used, keeping in mind considerations noted in9.3. The angle of pull shall be 90 to the surface. Forreproducible results, the rate of pull, the thickness and width ofthe strip, and deposit thickness must be standardized. Failure inthe coating/substrate interface is evidence of inadequate adhe-sio

40、n.11.2 The tensile and shear strengths of adhesives andsolders limit the range of adhesion strengths that can beevaluated. A quantitative analysis of the factors involved hasbeen published.312. Push Test12.1 Drill a blind hole 0.75 cm in diameter from theunderside until the point of the drill tip co

41、mes within approxi-mately 1.5 mm of the deposit/substrate interface on theopposite side. Supporting the material on a ring about 2.5 cmin diameter, apply steady pressure over the blind hole using ahardened steel punch 0.6 cm in diameter until a button sampleis pushed out.3Exfoliation or peeling of t

42、he coating in thebutton or crater areas is evidence of inadequate adhesion.12.2 Soft, very ductile, and thin deposits are generally notsuited for this technique.13. Scribe-Grid Test13.1 Scribe three or more parallel lines or a rectangular gridpattern on the article using a hardened steel tool ground

43、 to asharp (30) point with a distance between the scribed lines ofapproximately ten times the nominal coating thickness, with aminimum distance of 0.4 mm. In scribing the lines, usesufficient pressure to cut through the coating to the substrate ina single stroke. If any portion of coating between th

44、e linesbreaks away from the substrate, the adhesion is inadequate.13.2 When apparently satisfactory adhesion is indicated,apply a pressure-sensitive tape, having an adhesion bondstrength of at least 45 g/mm, using firm finger pressure onto aclean grid area. Make sure that any loose coating particles

45、 fromscribing do not remain. Shortly thereafter, remove the tape byseizing a free end and pulling it off rapidly (not jerked) backupon itself as close to an angle of 180 as possible. Theadhesion is not adequate if the tape has deposit adhering to itthat comes from the area between the scribed lines.

46、 Depositcontinuous to the scribed lines is not considered.13.2.1 The tape supplier4shall specify that their tape has asufficient adhesion bond strength. The tape shall be wideenough to cover three or more parallel lines of the scribed area.13.3 Generally, thick deposits are not suitable for evaluati

47、onunless a chisel or other sharp instrument is used to pry theexposed coating/substrate interface, in which case this tech-nique becomes a variant of Section 5.14. Test-Coating Systems14.1 Recommended adhesion tests for a variety of coatingsystems are given in Table 1.3Saubestre, E. B., Durney, L. J

48、., Hajdu, J., and Bastenbeck, E., Plating, Vol 52,October 1965, pp. 9821000.4Permacel 99, a product of and manufactured by Permacel, New Brunswick, NJ08903, is reported to be a suitable product for this purpose.B571 18315. Precision and Bias15.1 No statement is made about the precision and bias ofth

49、ese tests because of their qualitative nature.16. Keywords16.1 adhesion; metallic coatingsASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at an