Phosphate Coatings


Phosphating (also known under the trade name as Parkerizing™) is the chemical deposition of zinc or  manganese onto a part. The difference between the two types is primarily in the grain size of the crystals created during the process. The zinc phosphate tends to be a finer crystalline pattern, while manganese phosphate produces one that is more course. These patterns create more surface area on the part and an improved anchor profile for better adhesion for a subsequent coating. They also provide increased corrosion protection when applied with another coating.

Benefits:

• Prolong the life of organic coating
• Provide good paint bonding
• Improve corrosion resistance by providing a good base for absorbing and retaining rust preventative materials
• Provide an excellent base for holding lubricants and drawing compounds

Below is the most common specification for phosphate coating.

MIL-DTL-16232G
Type Z: Zinc phosphate coating
Class 4 – With no supplemental coating or coating as specified
Type M: Manganese phosphate coating
Class 4 – With no supplemental coating or coating as specified