How to judge whether an aluminum plate has been anodized

Among top anodized aluminum plate suppliers in China, we would like to share methods in judging whether an aluminum plate has been anodized. The difference between the appearances of an aluminium sheet before and after anodization is not too obvious, and it is difficult for green hands to distinguish two sheets out. The following methods are recommended to identify whether an oxide film has been formed on the surface of the part.

First, check the color of the plate surface

The surface roughness of a pure aluminum sheet on which the oxide film has been formed is lowered, and the cast aluminum and the miscellaneous aluminum are grayish black. The surface on which the oxide film is not formed is a bright white with a metallic luster.

Second, measure the electricity resistance of the plate

An anodized aluminum plate, with an oxide film with electricity resistance has been generated, is not conductive under normal pressure, while a common piece of sheet with no oxide film can conduct electricity.

Third, scratches

The surface of an anodized aluminum sheet plate on which the oxide film has been formed is very hard, slips when scratched, and has no scratches. The surface on which the oxide film is not formed is soft, and there is resistance and scratches when the needle is used.

Fourth, sound checking

An anodized aluminum plate gives off a crisp sound, while a muffled sound is generated when the oxide film is not formed.

In a word, you can judge whether an aluminum sheet has been anodized by checking its surface color, electricity resistance, scratches and sounds. All these methods are simple and practical. Hope they are helpful.