Industrial anodizing is anodizing to produce a finish where protection is the primary characteristic and appearance is secondary or of no importance.
Industrial anodizing produces anodic oxidation coatings that are mainly used to obtain:
- resistance to wear through abrasion or erosion;
- electrical insulation;
- thermal insulation;
- resistance to corrosion (when sealed).
However, where high quality wear resistance is the primary characteristic, the specifications for hard anodizing apply.
There are many products for automotive, medical or kitchen applications where appearance is not unimportant but resistance to wear processes and/or cleaning using aggressive chemical agents are particularly demanding of the properties of anodized aluminium.
Corrosion is a process that causes the degradation of metals. A familiar example is the rusting of iron and steel. Aluminium does not rust but can, nevertheless, suffer various forms of corrosion. Anodizing builds up a thick, protective oxide film on the metal surface. This acts as a barrier that can prevent aggressive chemicals reaching the aluminium.
Important product quality criteria include:
- visible defects
- Coating thickness
Protection against corrosion of the aluminium and micro-hardness can also be important depending on application.
The inspection of QUALANOD-licensed anodizing plants includes the testing of samples of anodized products to verify that the correct quality is being achieved.