Plasma multi-element co-permeation enhanced surface rare earth composite coating for steel part

The invention discloses a plasma multi-element co-permeation enhanced surface rare earth composite coating for a steel part, and relates to the field of composite coating preparation, and the preparation of the composite coating comprises the following steps: S1, mixing a chitosan solution and a rare earth metal compound solution according to a ratio of 100: 1, adjusting the pH value of the solution to 3-5, and stirring to obtain a mixed solution; cleaning the steel pipe by using a rotary polishing device for later use; and S2, further cleaning and drying the cleaned steel pipe, putting the steel pipe at a negative electrode position in an electro-deposition tank, and pouring the mixed solution in the S1 into the electro-deposition tank. Rubber rollers can drive a steel pipe to rotate through friction resistance between the rubber rollers and the outer wall of the steel pipe, the inner surface and the outer surface of the steel pipe can be polished through polishing plates in the rotating process of the steel