ASTM International test methods and specifications for anodic coatings, coating thickness measurement, hardness, corrosion resistance, and abrasion. These standards are referenced globally as the test methods of record for anodize QC.
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The reference test method for salt-spray (fog) corrosion testing of coatings, including anodic coatings on aluminium. Specifies test chamber temperature (35 ± 1.1 °C), salt solution concentration (5 ± 1% NaCl), pH (6.5 to 7.2), and spray collection rate (1-2 mL/h per 80 cm² horizontal area). Test duration is specified by the product standard being verified — typical anodize targets are 336 hours for sealed Type II coatings and 500-1000+ hours for sealed hard anodize. The most-cited corrosion-resistance test method globally.
The reference test method for non-destructive measurement of anodic coating thickness on aluminium using eddy-current instruments. Specifies probe calibration procedure (typically against shim foils traceable to gravimetric reference samples), measurement-area requirements (minimum surface area for valid reading), and reporting conventions. The production-floor instrument of record for anodize thickness QC in plants worldwide.
The reference abrasion-resistance test for organic and anodic coatings using a Taber abraser instrument. Standard wheel pairs are CS-10 (mild abrasion) and CS-17 (severe abrasion). Mass loss per 1000 cycles is reported. Properly run hard anodize on 6061 substrate typically shows 1.5-3.5 mg loss per 1000 cycles with CS-17 wheels — a key QC checkpoint for tribological applications.
The reference adhesion test for organic coatings (including powder coatings) on metallic substrates. Test method A is an X-cut for thick coatings; Method B is a cross-hatch (typically 6x6 or 11x11 grid) for thinner coatings. Adhesion is rated on a 0-5 scale (5B = no flaking; 0B = greater than 65% removal). The production-floor QC method of record for powder coat adhesion on aluminium and steel substrates.
Simple, rapid scratch-hardness test for organic coatings using calibrated drawing pencils (6B softest through 9H hardest). The hardest pencil that does NOT mar the coating defines the film hardness rating. Used widely for powder coat QC where Taber abrasion is impractical for production-floor screening. Typical architectural powder coatings rate 2H or harder.
Reference impact-resistance test for organic coatings on metal, including powder coatings. A weighted indenter (typically 1 kg) is dropped from a calibrated height onto a coated panel; the coating is examined for cracking, chipping, or loss of adhesion. Used in QC for automotive, architectural, and industrial powder coat applications where impact resistance is specified.
Reference method for Vickers and Knoop microhardness testing of thin coatings, including hard anodize. Specifies indenter load selection (typically 25-100 gf for hard anodize at 30-75 μm thickness), measurement procedure on metallographic cross-sections, and reporting. Hard anodize microhardness is typically reported as HV50 (Vickers at 50 gf load); properly run hard anodize on 6061 alloy typically achieves >400 HV50.
Test method for measuring the electrical admittance (or impedance) of sealed anodic coatings. The admittance value correlates inversely with seal quality — a properly sealed coating shows low admittance, an unsealed or poorly sealed coating shows high admittance. Used as a non-destructive seal-quality QC method alongside the dye-stain test (ISO 2143) for sealed anodize batches.