Manganese phosphate makes the moving parts of machines slide easily and provides protection against corrosion. It reduces the friction between metals. Manganese phosphate coating has more stable structure than zinc phosphate under high pressure and high temperature. It is commonly used in piston and weapon industries.

As in the other surface treatment applications, it can be applied only on the degreased surfaces. It is necessary to set up a activation bath. Temperature, waiting time, concentration, free and total acid points are the parameters that must be paid attention to. It is used at 70-95ºC with % 15-20 bath concentration and with 5-25 min. immersion. Manganese phosphate forms a grey-black and 4-40 gr/m² coating and it can not be used as under paint.