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A Beginner’s Guide to Phosphate Coating

Phosphate coating is the crystalline coating applied on the ferrous metals to inhibit corrosion. The phosphate coating lends a gray to black appearance of the surface.

In many applications, phosphate coating is followed by oil coating (P & O) to improve its rusting and anti-galling properties.

In this post, we will introduce you to different types of phosphate coating, their industrial applications, and their benefits.

Types of Phosphate Coating

Phosphate coatings are divided into two types as shown below.

Manganese Phosphate Coating – Type M:

The manganese phosphate coatings are available in black and dark gray colors. They are used as corrosion protection agents, anti-galling agents, and as a lubricant.

These coatings have the highest hardness and superior corrosion resistance among all general phosphate coatings.

The treatment time often varies from five to fifteen minutes. Some of its features and applications are:

  • These coatings are applied by immersion to bearings, bushings, fasteners, and other common industrial products.
  • The coatings are used for sliding products like transmission systems, motor vehicle components in brake and clutch assemblies, engine components, leaf or coil springs


Zinc Phosphate Coatings – Type Z:

Zinc phosphate coating is mainly used as rust-proofing. These coatings are usually applied by spraying or immersion.

The zinc phosphate coatings are available in black and dark gray colors and are lighter in comparison to manganese phosphate coatings.

Industries using Phosphate Coatings

Phosphate coatings are utilized in various industries. Below are some of the industries served.

  • Hydraulic system manufacturers
  • Cold-forming industries
  • Heavy equipment manufacturers
  • Gear & bearing manufacturers
  • Electrical connector manufacturers
  • Military armament suppliers
  • Nuclear component fabricators


Advantages of Phosphate Coating

The following are a few advantages of using phosphate coatings

  • Phosphate coating provides strong adhesion and corrosion protection, and also improves the friction properties of sliding components.
  • Some of the threaded parts are treated with phosphate coatings, which improves their anti-galling and rust-inhibiting characteristics.
  • Zinc phosphate coatings are used as Chemical Agent Resistant Coating (CARC) paints on military equipment including munitions, aviation, and ground. This helps them withstand harsh environmental conditions.


All the above-given information validates why phosphate coating is gaining popularity across various industries. Along with selecting the coating for your industrial application, it is very important that you procure them from a well-known manufacturer.

Microsurface Corporation in San Jose, California is one of the leading and well-known applicators of engineered lubricants, coatings, and manufacturer of Timesaver Lapping Compounds.

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