OIL REMOVAL, RUST REMOVAL AND PHOSPHORIZATION COMBINATION COATING AGENT, STEEL PIECE AND SURFACE COATING METHOD THEREFOR

摘要

An oil removal, rust removal, and phosphorization combination coating agent, a steel piece and a surface coating method therefor. The oil removal, rust removal, and phosphorization combination coating agent is used for pretreatment on the surface of a steel piece, and comprises, on the basis of 1000 parts by weight, the following components in parts by weight: 20-80 parts of phosphoric acid, 6-30 parts of sodium carbonate, 1-4.5 parts of nickel nitrate, 0.1-0.45 parts of copper sulfate, 1-6 parts of sodium molybdate, 0.05-3 parts of citric acid monohydrate, 0.1-3 parts of a surfactant, and the balance of water. The oil removal, rust removal, and phosphorization combination coating agent above can simultaneously remove oil contamination and rust, and form a film layer, the film having a fine layer structure and firm adhesion; and the oil removal, rust removal, and phosphorization combination coating agent can form a colored film on the surface of steel, has a good corrosion resistance and is capable of improving the adhesion of a subsequent coating.