Spray coating is also called thermal spraying. The technology of spraying molten spraying materials to the surface of metal, alloy, plastic, ceramics and other workpieces with a power device to form a complete coating.The spraying material can be metal or nonmetal, which can be melted or softened by heat source, atomized or pushed by the power of heat source itself or compressed air flow to form spray particles, and sprayed to the substrate surface at a certain speed to form a coating.The heat sources used include gas burning flame, gas discharge heating, electric heating and laser.After spraying, the workpiece can improve its corrosion resistance, heat resistance and wear resistance, increase its thickness or repair size, etc