The processes described in this practice clean and provide a paint base for the finishing of magnesium and magnesium alloys. Service conditions will determine, to some degree, the specific process to be applied.

1. Scope

1.1 This practice covers a guide for metal finishers to clean and then provide a paint base for the finishing of magnesium and magnesium alloys using chemical conversion coatings. Where applicable (for example, aerospace) secondary supplementary coatings (for example, surface sealing) can be used (see Appendix X1).

1.2 Although primarily intended as a base for paint, chemical conversion coatings provide varying degrees of surface protection for magnesium parts exposed to indoor atmosphere either in storage or in service under mild exposure conditions. An example is the extensive use of the dichromate treatment (see 5.2) as a final coating for machined surfaces of die cast magnesium components in the computer industry.

1.3 The traditional numbering of the coating is used throughout.

1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.5 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.

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

SAE Standard

Military Specifications

Keywords

chemical conversion coatings; chromates; cleaning magnesium; preparation for painting; protection; surface sealing ^INDEX TERMS: Acid pickling treatment; Chrome-manganese treatment; Chrome pickle treatment; Conversion coatings; Dichromate coatings; Galvanic chromate coatings; Magnesium; Magnesium alloys; Nonelectrolytic conversion coatings; Phosphate treatment; Semi-bright pickle treatment;

ICS Code

ICS Number Code 77.120.20 (Magnesium and magnesium alloys)

Citing ASTM Standards

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