Manganese Phosphate

Manganese phosphate — commonly known as Parkerizing — is one of the most established and reliable chemical conversion coatings in industrial use. Rather than depositing a foreign material onto the surface, the process chemically converts the outermost layer of the ferrous substrate itself into a stable, porous crystalline manganese phosphate compound.

The conversion process begins with surface preparation involving media blasting to remove oxides and contamination, activating the surface for chemical conversion. Parts are then immersed in a heated manganese phosphate bath at 82–99°C where the reaction forms a tightly bonded crystalline layer across all surfaces simultaneously — including internal bores, complex geometries, and threaded features. Coating weight for Type M (Manganese base) is 16.1 g/m², producing a uniformly gray to black surface.

Post-treatment with oil or supplemental sealers dramatically improves corrosion resistance and provides critical break-in lubrication. The inherent porosity of the crystalline structure absorbs and retains lubricants far more effectively than a smooth metal surface, reducing friction during component run-in and extending service life. Manganese phosphate also serves as an ideal base for paint, dry film lubricants, and other supplemental coatings.