Sandblast-free corrosion-proof composite coating for thermal spraying and preparation process thereof

The invention relates to a sandblast-free corrosion-proof composite coating for thermal spraying in the technical field of metal corrosion protection, comprising a rusty primer and a sandblast-free roughened layer, wherein rusty primer is obtained by mixing and applying the following materials: a rusty primer component A: a modified epoxy resin, a medium oil semidry alkyd resin, a highly iminatedbutyl-etherified melamine resin having the degree of etherification of 4, a solvent and a rusty primer component B; and the sandblast-free roughened layer is composed of a sandblast-free roughened layer component A: ferrophosphorus powder, aluminum trippolyhosphate, mica powder, an epoxy resin, propylene glycol methyl ether acetate, dimethylbenzene, a sandblast-free roughened layer component B and stuffing. The preparation process of the sandblast-free corrosion-proof composite coating for thermal spraying comprises applying the rusty primer to a corroded steel surface, and spraying the sandblast-free roughened layer to the rusty primer at the normal temperature in 24 h. Therefore, the problems of high energy consumption and pollution of sandblasting are eliminated; the steps of construction are simplified; the difficulty and cost of construction are reduced; the corrosion protection effect is guaranteed; the environmental pollution is reduced; and the application range of the composite coating is wider.