ASTM_B_765_-_03_2013.pdf

Designation:B76503(Reapproved 2013)Standard Guide forSelection of Porosity and Gross Defect Tests forElectrodeposits and Related Metallic Coatings1This standard is issued under the fixed designation B765;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide describes some of the available standardmethods for the detection,identification,and measurement ofporosity and gross defects in electrodeposited and relatedmetallic coatings and provides some laboratory-type evalua-tions and acceptances.Some applications of the test methodsare tabulated in Table 1 and Table 2.1.2 This guide does not apply to coatings that are producedby thermal spraying,ion bombardment,sputtering,and othersimilar techniques where the coatings are applied in the form ofdiscrete particles impacting on the substrate.1.3 This guide does not apply to beneficial or controlledporosity,such as that present in microdiscontinuous chromiumcoatings.1.4 Porosity test results(including those for gross defects)occur as chemical reaction end products.Some occur in situ,others on paper,or in a gel coating.Observations are made thatare consistent with the test method,the items being tested,andthe requirements of the purchaser.These may be visualinspection(unaided eye)or by 10 magnification(micro-scope).Other methods may involve enlarged photographs orphotomicrographs.1.5 The test methods are only summarized.The individualstandards must be referred to for the instructions on how toperform the tests.1.6 The values stated in SI units are to be regarded asstandard.The values given in parentheses are for informationonly.1.7 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2B276 Test Method for Apparent Porosity in Cemented Car-bidesB374 Terminology Relating to ElectroplatingB537 Practice for Rating of Electroplated Panels Subjectedto Atmospheric ExposureB542 Terminology Relating to Electrical Contacts and TheirUseB545 Specification for Electrodeposited Coatings of TinB605 Specification for Electrodeposited Coatings of Tin-Nickel AlloyB650 Specification for Electrodeposited Engineering Chro-mium Coatings on Ferrous SubstratesB689 Specification for Electroplated Engineering NickelCoatingsB733 Specification for Autocatalytic(Electroless)Nickel-Phosphorus Coatings on MetalB734 Specification for Electrodeposited Copper for Engi-neering UsesB735 Test Method for Porosity in Gold Coatings on MetalSubstrates by Nitric Acid VaporB741 Test Method for Porosity In Gold Coatings On MetalSubstrates By Paper Electrography(Withdrawn 2005)3B798 Test Method for Porosity in Gold or Palladium Coat-ings on Metal Substrates by Gel-Bulk ElectrographyB799 Test Method for Porosity in Gold and PalladiumCoatings by Sulfurous Acid/Sulfur-Dioxide VaporB809 Test Method for Porosity in Metallic Coatings byHumid Sulfur Vapor(“Flowers-of-Sulfur”)B866 Test Method for Gross Defects and Mechanical Dam-age in Metallic Coatings by Polysulfide ImmersionB877 Test Method for Gross Defects and Mechanical Dam-age in Metallic Coatings by the Phosphomolybdic Acid(PMA)Method1This guide is under the jurisdiction of ASTM Committee B08 on Metallic andInorganic Coatings and is the direct responsibility of Subcommittee B08.10 on TestMethods.Current edition approved Dec.1,2013.Published December 2013.Originallyapproved in 1986.Last previous edition approved in 2008 as B765 93(2008).DOI:10.1520/B0765-03R13.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.Terminology3.1 DefinitionsMany terms used in this guide are definedin Terminology B374 or B542.3.2 Definitions of Terms Specific to This Standard:3.2.1 porosityfor the purpose of this guide,porosity in acoating is defined as any hole,crack,or other defect thatexposes the underlying metal to the environment.Differencesbetween the major types of porosity are described in Section 5.3.2.2 underplatea metallic coating layer between the basismetal and the topmost metallic coating.The thickness of anunderplating is usually greater than 1 m,in contrast to a strikeor flash,which are usually thinner.4.Significance and Use4.1 Porosity tests indicate the completeness of protectio