ASTM B921 - 08(2013)

    Standard Specification for Non-hexavalent Chromium Conversion Coatings on Aluminum and Aluminum Alloys

    Active Standard ASTM B921 | Developed by Subcommittee: B08.07

    Book of Standards Volume: 02.05


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    ASTM B921

    Abstract

    This specification covers the requirements relating to rinsed and non-rinsed non-hexavalent chromium conversion coatings on aluminum and aluminum alloys intended to retard corrosion; as a base for organic films including paints, plastics, and adhesives; and as.a protective coating having a low electrical contact impedance. Coatings are categorized into four classes according to corrosion protection and finish. The type of conversion coating depends on the composition of the solution and may also be affected by pH, temperature, duration of the treatment, and the nature and surface condition. Films are normally applied by dipping, but may also be applied by inundation, spraying, roller coating, or by wipe-on techniques. Coatings shall adhere to specified electrical resistance, adhesion, and corrosion resistance requirements.

    This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.

    1. Scope

    1.1 This specification covers the requirements relating to rinsed and non-rinsed non-hexavalent chromium conversion coatings on aluminum and aluminum alloys intended to give protection against corrosion and as a base for other coatings.

    1.2 Aluminum and aluminum alloys are conversion coated in order to retard corrosion; as a base for organic films including paints, plastics, and adhesives; and as a protective coating having a low electrical contact impedance.

    1.3 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 requirements prior to use.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    B117 Practice for Operating Salt Spray (Fog) Apparatus

    B602 Test Method for Attribute Sampling of Metallic and Inorganic Coatings

    D1730 Practices for Preparation of Aluminum and Aluminum-Alloy Surfaces for Painting

    D3359 Test Methods for Measuring Adhesion by Tape Test

    ISO Standards

    ISO2409 Paint and Varnishes--Cross-Cut Test Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.

    ISO3768 Metallic Coatings--Neutral Salt Spray Test (NSS Test)

    ISO4519 Electrodeposited Metallic Coatings and Related Finishes--Sampling Procedures for Inspection by Attributes

    Federal Standard

    Fed.Std.No.141 Paints, Varnish, Lacquer, and Related Materials; Methods of Inspection Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://dodssp.daps.dla.mil.

    Military Specification

    MIL-DTL-5541 Chemical Conversion Coatings on Aluminum and Aluminum Alloys

    MIL-DTL-81706 Chemical Conversion Materials For Coating Aluminum and Aluminum Alloys


    ICS Code

    ICS Number Code 77.120.10 (Aluminium and aluminium alloys)

    UNSPSC Code

    UNSPSC Code 11172000(Aluminum based alloys)


    DOI: 10.1520/B0921-08R13

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