Principle Of Zinc Spraying Machine

For cast iron pipes buried underground, working in general soil environment, the outer wall can only be coated with asphalt to meet the requirements of anti-corrosion. However, for highly corrosive soils, such as swampy soil, muddy soil, sulfate-containing soil, garbage dirty soil and soil polluted by drainage, the anti-corrosion effect of only coating asphalt is unsatisfactory. The French Musongqiao Company began to carry out the pipe simulation comparison experiment in 1949. The results showed that the anti-corrosion effect of the composite coating was the best after the pipe was annealed to retain the oxide scale, and then sprayed with zinc and then coated with asphalt. Zinc coating has two functions: 1. Since the electrochemical point of zinc is lower than that of iron, the reaction of zinc can protect the iron pipe from corrosion; 2. When the zinc layer is corroded by salt solution, insoluble compounds ( Zinc phosphate, zinc chloride, zinc sulfate) cover the surface of the pipe, thereby slowing the intrusion of corrosive media.