Phosphate Conversion Coating

Offering phosphate coating finishing services appropriate for a variety of industrial markets, Keystone Corporation offers both rack* and barrel applications that are uniquely tailored to meet the specific needs of our clients. 

Phosphate coating is often used on steel parts in order to provide corrosion protection, lubricity, or as a pretreatment for further coatings such as paint or powder coating.  The finish provided by the phosphate coating will be gray to black in appearance.  Whether on steel, cast iron, or powdered metal, our zinc and manganese phosphate coatings provide a more affordable and visually pleasing option to alternative finishes, and still deliver excellent corrosion resistance, prolong the life of organic coatings, provide an excellent base for lubricants, and can be used as a pre-treatment for paint.


Phosphate Coating Applications

Keystone Corporation offers 2 types of phosphate coatings:

  • Manganese Phosphate (Type M)
    • Produces non-metallic, oil-absorptive coating on iron and steel rearing surfaces
  • Zinc Phosphate (Type Z)
    • Produces micro crystalline coatings which are best for corrosion resistance or subsequent painting



  • TT-C-490D - For light phosphate
  • MIL-DTL-16232 - For heavy phosphate


*Keystone Corporation can process parts up to 9 feet in length that weigh up to 8,000 pounds

For More Information About Phosphate Coating, Contact us today by phone, email, or through the Quote Request link on this page.  Our staff is ready to meet your needs.


Plated metal parts

 Phosphate Coating


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