Mil-STD-171, Mil-DTL-16232 Type M & Z HP4-7 Type M & Z (Boeing), M690007 (Honeywell)

Phosphate coatings provide a crystalline corrosion resistant surface for ferrous metals. The phosphate coatings are generally porous and provide a micro-sponge like layer that will hold supplemental oil treatments or provide a bonding surface for subsequent paint operations. The coatings provide corrosion resistance and wear resistance and are commonly used for treating gears, splines, pistons, cams, firearms, aircraft components and military equipment.