What is the function of chromic acid oxidation in aluminum and aluminum alloys?

The chromic acid anodic oxidation method is mainly used for the processing of high-precision precision parts. The oxide film obtained is thick (2-5 μm). The film is soft and has good toughness. It can maintain the original precision and finish of the parts and basically does not reduce the fatigue strength of the raw materials. The chromic acid oxidation solution can also check metallurgical defects such as grain size and fiber direction cracks of the material. Due to the low dissolution rate of aluminum products, it is commonly used in the aviation industry for the oxidation of aluminum parts with high strength and precision of the engine, such as rotor blade bushings, wheels, etc. It may also be used for other precision parts of aluminum products. Oxidation treatment. Due to the strict water treatment requirements of chromic acid, the application of this method is limited. Chromic acid anodic oxidation formula and process are as follows: Chromate (Cr03) 5%～10% Voltage 40V Current density 0.3 ~ 1A/dm2 Temperature 30～45°C When the anodic oxidation using chromic acid method, it is appropriate to use distilled water to prepare, the chloride ion content must be strictly controlled below 0.02%.