Manganese phosphate coating is a metal surface treatment method commonly used for steel and other metal materials. Its primary purpose is to enhance the metal surface's corrosion resistance, wear resistance, and anti-corrosion properties. This treatment involves immersing the metal in a manganese phosphate solution to deposit a layer of manganese phosphate salt on the metal surface, forming a protective coating.

The combination of heat treatment, sandblasting, and manganese phosphate coating is a standard procedure for steel and iron components. In the oxidation-reduction reaction, heat treatment plays a crucial role, as carbon is an essential element in the oxidation-reduction process. The wear resistance of manganese phosphate coating is superior to zinc phosphate coating, which helps reduce stress and enhance lubrication by decreasing the pressure on the coating. Lubricants such as graphite or molybdenum disulfide are often used on the surface of the coating to further improve its lubricating effect. The coating consists of porous crystalline structures, which provide good absorption and retention properties, effectively assisting in the lubrication of rotating and moving parts. Manganese phosphate and zinc phosphate coatings differ in color, with manganese phosphate appearing black, dark gray, or light gray. Manganese phosphate coating can exhibit a shiny black appearance after proper crystallization.