The surface BAI principle can be divided into four DU planes:

1. Mechanical surface treatment: sandblasting zhi, blasting dao pill, Zhuan polishing, SHU rolling, polishing, brushing, spraying, painting, oiling, etc.

2. Chemical surface treatment: blue and black, phosphating, pickling, electroless plating of various metals and alloys, TD treatment, QPQ treatment, chemical oxidation, etc.

3. Electrochemical surface treatment: anodic oxidation, electrochemical polishing, electroplating, etc.

4. Modern surface treatment: chemical vapor deposition CVD, physical vapor deposition PVD, ion implantation, ion plating, laser surface treatment, etc.