The process does not contain hexavalent chromium, the plating solution is stable, the controllability is good, the operation is easy to open the tank, the coating is close to the color of the hexavalent chromium coating, the coating has good corrosion resistance and never changes color, high temperature resistance, high density, and is not easy to produce mildew spots , the deposition speed is fast, the deposition rate is 0.077μm/min, the coating thickness is above 0.3 μm, the plating solution has high deep plating ability, no harmful gas is produced, and it is safer for operators.