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Black anodized aluminum sheet process and test methods

June 6, 2019

The black anodized aluminum sheet refers to an aluminium sheet that has gone through anodizing process and obtained a black film on the surface. Anodizing refers to a material protection technique in which a metal material forms an oxide film on the surface thereof by applying an anode current in an electrolyte solution. If not specifically indicated, the solution applied in the process is usually sulfuric acid. Surface treatment technology has become an indispensable part in overcoming the defects of surface hardness and wear resistance, expanding the application range and prolonging the service life of aluminum alloys, and anodizing technology proves to be the most successful.

black anodized aluminum sheet

A black anodized aluminum sheet is obtained by dying an anodized sheet with the solution of acid hair element ATT 20~30g/L and acid lake blue 2~3g/L at the temperature between 50 and 70°C for 10 to 15minutes, and the pH of the solution should be kept between 3 and 3.5 (or 4.5~5.5).

There are three test methods for the black anodized aluminum sheet. First, you can measure the film thickness with a thickness gauge. Second, check about discoloration. You can soak the sheet with organic solvent (general alcohol), if the color is faded, it is either dyed or less. You can ask him to do black matter anodizing, by which the color will never fade, because the film itself is black. The third is hardness test. Find a commonly used aluminum material to process a tip, and then use it to scratch the sheet surface. If scratches come into being on the surface, it proves that the hardness is problematic, because an anodized aluminum sheet is so hard that the oxide film will not be destroyed. There might be white marks from the test tool, but no dots should be felt on the surface of the sheet.

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