What standards define the performance of arc anodizing for industrial components?

Key Standards Governing Arc Anodizing Performance

The performance of Arc Anodizing for industrial components is defined by a suite of international standards that specify coating properties, performance metrics, and quality control methods. The most critical specifications focus on the coating's physical and protective characteristics, which are essential for demanding applications.

Coating Property and Composition Standards

The foundational standard for anodized coatings is often MIL-A-8625, which categorizes anodic films. Arc Anodizing, as a type of hard coat anodizing, falls under Type III within this specification. This classification mandates a minimum coating thickness, typically 50.8 µm (2 mils), which is significantly thicker than decorative Type II coatings. For components requiring extreme abrasion resistance, standards like AMS 2469 (Aerospace Material Specification) are frequently invoked, which may call for even greater thicknesses and control over the coating's density and microstructure. The alloy substrate itself, such as those defined in our Die Cast Aluminum Alloys list, must be compatible to achieve these robust coatings without defects.

Performance and Testing Standards

Performance validation is conducted against standardized test methods that quantify the coating's durability:

Abrosion and Wear Resistance: Hardness is commonly measured using the ASTM B647 (Knoop indentation) or ASTM E384 (Vickers microindentation) tests. A properly executed Arc Anodize coating will typically exhibit a minimum Knoop hardness of 400 HK under a 500-gram load, often reaching much higher values. Wear resistance can be quantified via ASTM G65 (Dry Sand/Rubber Wheel test).

Corrosion Resistance: The benchmark test is ASTM B117 (Salt Spray Test). While standard anodizing may target 96-300 hours, a fully sealed, thick Arc Anodized coating is often specified to withstand 1000 hours or more without significant corrosive pitting. The quality of the seal, critical for this performance, is verified by ASTM B136 (Phosphoric Acid Dip Test) or ASTM B680 (Impedance Test).

Adhesion and Coating Integrity: Adhesion is typically verified using ASTM D3359 (Tape Test), where the coating must not detach. For high-integrity components that undergo Post Machining, these tests are critical to ensure the coating remains bonded at edges and machined features.

Industry-Specific Specifications

Beyond generic standards, many industrial sectors impose their own stringent specifications. Automotive, aerospace, and defense contractors often have proprietary standards that reference or exceed the common MIL and ASTM documents. For instance, a project involving power tools or automotive hardware would require the Arc Anodizing process to be qualified to the client's specific internal performance criteria, which often include cyclic corrosion testing and mechanical impact tests tailored to the component's real-world operating environment.