The process of Phosphate coating is employed for the purpose of pretreatment prior to coating or painting, increasing corrosion protection and improving friction properties of sliding components. Metal coating offers both zinc phosphate and manganese phosphate coating. Manganese phosphate coating is applied when wear resistance and anti-galling properties are required. Manganese phosphate also possesses the ability to retain oil, which further improves anti-friction properties and imparts corrosion resistance to the coated parts. Zinc and manganese coatings are used to help break in components subject to wear and help prevent galling. Most phosphate coatings serve as a surface preparation for further coating and/or painting, a function it performs effectively with excellent adhesion and electric isolation.

The process of phosphating aluminum and steel parts is typically listed as a conversion coating because the process involves metal removal as part of the reaction. However, it is not like anodizing or black oxide in that the phosphate coating is actually a precipitation reaction.

3 Types of Phosphating. Phosphating is a conversion coating applied to Steel and Iron components. In its basic form, the process involves immersing a component in a dilute solution, which converts the surface of the metal into a layer of microscopic Phosphate Crystals.

Corrosion resistance and resistance to detergents are also higher when compared to Zinc Phosphate. Appearance is gray. Manganese Phosphate: Used primarily on friction and bearing surfaces to prevent meal-to-metal contact and reduce wear. This coating is also used as a base for dry film lubricants. The following is a typical phosphating procedure: Cleaning the surface, Rinsing, Surface activation, Phosphating, Rinsing, Neutralizing rinse (optional), and Drying.

The main applications of phosphating are:
Corrosion protection in conjunction with organic coatings, such as paints and polymer films
Facilitation of cold-forming processes, such as wire drawing and tube drawing, or deep drawing
Corrosion protection in conjunction with oils and waxes
Corrosion protection with no subsequent treatment
Improving anti-friction properties, such as break-in, wear resistance, anti-galling and coefficient of friction
Providing strong adhesion bonding for subsequent painting or other organic coating