Heartland provides two types of coatings: zinc and manganese phosphating. Zinc and manganese phosphate coatings are the treatment of iron or steel by immersion in a dilute solution of phosphoric acid and other additives. During the resulting chemical reactions, the surface of the metal is chemically converted to an integral protective layer of insoluble zinc or manganese crystals. Depending on the physical characteristics of the substrate and the pretreatment methods used, the translucent crystals appear black to light grey in color for zinc phosphate and black to black to dark grey in color for manganese phosphates.
Zinc phosphates are used for rust proofing, lubricity, and as a paint/coating base. Manganese phosphates are used for corrosion resistance and lubricity.
Manganese phosphating is generally preferred for lubricity during break in because of its higher wear resistance. Manganese phosphates permit rapid break-in of moving parts without scuffing or welding by preventing metal to metal contact, as the friable coating is easily crushed when a load is applied. Additionally, the oil held by the crystals improves the lubrication of the treated surface and imparts corrosion resistance. After break-in, an even and fine distribution of oil reservoirs remains, assuring continued lubrication. This is why pistons are frequently coated with manganese phosphates.