Electro-less nickel plating is a chemical process that deposits an even layer of nickel phosphorus alloy on the surface of a solid substrate (metal). The process involves dipping the substrate in a water solution containing nickel salt and a phosphorus-containing reducing agent. Electro-less nickel plating is a process that requires depositing a nickel alloy from aqueous solutions onto a substrate without the use of electric current. Therefore, it differs from electroplating which depends on an external source of direct current to reduce nickel ions in the electrolyte to nickel metal on the substrate. Electro-less nickel plating is a chemical process which reduces nickel ions in a solution to nickel metal by chemical reduction.

Zinc phosphate coating is formed througha process of crystallization on the surface by a chemical reaction. The Zinc phosphate process should be applied by immersion, and it can be used for any phosphate application.

Manganese phosphate phosphate is used both for corrosion resistance and lubricity. It is applied by immersion.