This specification covers the requirements for porous oxide coatings deposited by electrolysis on aluminum and aluminum alloy parts. These coatings should have good appearance, abrasion resistance, electrical properties, and protection against corrosion and does not include nonporous barrier layer anodic coatings that are used for electrical capacitors. The basis metals for these coatings should be subjected to mechanical finishing operations, cleaning, and chemical or electrolytic pre-treatments to yield coatings with fine quality and appearance. Anodized parts should be sealed in water or aqueous chemical solutions except when otherwise specified. Each anodic coating should be continuous, smooth, adherent, uniform in appearance, and free of powdery areas (burns, loose films, stains, discolorations, and discontinuities.
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.
1.1 This specification covers requirements for electrolytically formed porous oxide coatings on aluminum and aluminum alloy parts in which appearance, abrasion resistance, electrical properties, and protection against corrosion are important. Nonporous, barrier layer anodic coatings used for electrical capacitors are not covered. Seven types of coatings as shown in Table 1 are provided. Definitions and typical examples of service conditions are provided in Appendix X1.
Note 1—It is recognized that uses exist in which modifications of the coatings covered by this specification may be required. In such cases the particular properties desired by the purchaser should be the subject of agreement between the purchaser and the manufacturer.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
TABLE 1 Anodic Coatings Descriptions
Note—Hard coatings may vary in thickness from 12 μm to more than 100 μm. If the thickness of Type A is not specified, it shall be 50 μm min. Type A coatings will not be sealed unless so specified.
|Type||Coating (Industry) Description||Minimum Film Thickness (μm)|
|A||Engineering Hard Coat||50|
|B||Architectural Class I||18|
|C||Architectural Class II||10|
|E||Interior—Moderate Abrasion|| 5.0|
|F||Interior—Limited Abrasion|| 3|
|G||Chromic Acid|| 1|
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
B110 Method for Testing Dielectric Strength of Anodically Coated Aluminum
B117 Practice for Operating Salt Spray (Fog) Apparatus
B136 Method for Measurement of Stain Resistance of Anodic Coatings on Aluminum
B137 Test Method for Measurement of Coating Mass Per Unit Area on Anodically Coated Aluminum
B244 Test Method for Measurement of Thickness of Anodic Coatings on Aluminum and of Other Nonconductive Coatings on Nonmagnetic Basis Metals with Eddy-Current Instruments
B368 Test Method for Copper-Accelerated Acetic Acid-Salt Spray (Fog) Testing (CASS Test)
B457 Test Method for Measurement of Impedance of Anodic Coatings on Aluminum
B487 Test Method for Measurement of Metal and Oxide Coating Thickness by Microscopical Examination of Cross Section
B538 Method of FACT (Ford Anodized Aluminum Corrosion Test)
B602 Test Method for Attribute Sampling of Metallic and Inorganic Coatings
D658 Test Method for Abrasion Resistance of Organic Coatings by Air Blast Abrasive
E429 Test Method for Measurement and Calculation of Reflecting Characteristics of Metallic Surfaces Using Integrating Sphere Instruments
E430 Test Methods for Measurement of Gloss of High-Gloss Surfaces by Abridged Goniophotometry
MIL-STD-414 Sampling Procedures and Tables for Inspection by Variables for Percent Defective
Aluminum alloys--specifications; Aluminum alloys (anodic coatings)--specifications; Aluminum coatings--specifications; Anodic coatings--Al/Al alloys);
ICS Number Code 25.220.20 (Surface treatment)
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