ASTM_B_840_-_15.pdf

Designation:B84015Standard Specification forElectrodeposited Coatings of Zinc Cobalt Alloy Deposits1This standard is issued under the fixed designation B840;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 specification covers the requirements for electrode-posited zinc cobalt alloy coatings on metals.1.2 The following precautionary caveat pertains to the testmethod portion only,Section 8,of this specification:Thisstandard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2.Referenced Documents2.1 ASTM Standards:2B117 Practice for Operating Salt Spray(Fog)ApparatusB183 Practice for Preparation of Low-Carbon Steel forElectroplatingB242 Guide for Preparation of High-Carbon Steel for Elec-troplatingB320 Practice for Preparation of Iron Castings for Electro-platingB322 Guide for Cleaning Metals Prior to ElectroplatingB374 Terminology Relating to ElectroplatingB487 Test Method for Measurement of Metal and OxideCoating Thickness by Microscopical Examination ofCross SectionB499 Test Method for Measurement of Coating Thicknessesby the Magnetic Method:Nonmagnetic Coatings onMagnetic Basis MetalsB504 Test Method for Measurement of Thickness of Metal-lic Coatings by the Coulometric MethodB507 Practice for Design of Articles to Be Electroplated onRacksB568 Test Method for Measurement of Coating Thicknessby X-Ray SpectrometryB571 Practice for Qualitative Adhesion Testing of MetallicCoatingsB602 Test Method for Attribute Sampling of Metallic andInorganic CoatingsB697 Guide for Selection of Sampling Plans for Inspectionof Electrodeposited Metallic and Inorganic CoatingsB762 Test Method of Variables Sampling of Metallic andInorganic CoatingsB849 Specification for Pre-Treatments of Iron or Steel forReducing Risk of Hydrogen EmbrittlementB850 Guide for Post-Coating Treatments of Steel for Reduc-ing the Risk of Hydrogen EmbrittlementD3951 Practice for Commercial Packaging3.Terminology3.1 DefinitionsMany terms used in this specification aredefined in Terminology B374.3.2 Definitions of Terms Specific to This Standard:3.2.1 significant surface,nthat portion of a coated arti-cles surface where the coating is required to meet all therequirements of the coating specification for that article.Significant surfaces are usually those that are essential to theserviceability or function of the article or can be a source ofcorrosion products or tarnish films that interfere with thefunction or desirable appearance of the article.Significantsurfaces are those surfaces that are identified by the purchaserby,for example,indicating them on an engineering drawing ofthe product or marking a sample item of the product.4.Classification4.1 There is one coating class,and it is defined as Class1a zinc cobalt alloy that is approximately 99%by mass zincand at minimum 0.5%by mass cobalt.4.2 There are five coating types and they are defined asfollows:4.2.1 Type AWith colorless(blue bright)chromate con-version coatings.4.2.2 Type BWith yellow chromate conversion coating.4.2.3 Type CWith bronze chromate conversion coating.4.2.4 Type DWith black chromate conversion coating.4.2.5 Type EAny of the above types plus organic topcoat.NOTE1Whereas colored chromate conversion coatings are usuallymeant to include various shades of yellow to bronze when used with1This specification is under the jurisdiction of ASTM Committee B08 onMetallic and Inorganic Coatingsand is the direct responsibility of SubcommitteeB08.06 on Soft Metals.Current edition approved May 1,2015.Published May 2015.Originallyapproved in 1993.Last previous edition approved in 2009 as B840 99(2009).DOI:10.1520/B0840-15.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 non-alloyed zinc,yellow and bronze chromate conversion coatings areconsidered distinctly different when applied to alloyed zinc coatings andare formulated specifically to produce the desired coating.4.3 There are three grades according to thickness and aredefined as follows:Minimum Thickness,mNew ASTM GradeOld ASTM Grade66112122181835.Ordering Information5.1 In order to make the application of this specificationcomplete,the purchaser needs to supply the following infor-mation to the seller in the purchase order and drawings.5.1.1 Title,ASTM designation number,and date of issue ofthis