Surfix MN 641 / 643 Description Application: Manganese-Iron phosphate coating on steel and iron surfaces. The Growel Advantage: This set of products leaves a non-metallic, oil absorptive, crystalline, black/dark-grey coating to reduce wear and prevent galling of moving parts, such as bearing surfaces like pistons, piston rings, shafts, gears, cylinders and all types of machine parts wherever wear is a constant factor to be considered. (Coating Wt. 750-3000 mg/sq.ft, meets IS specification 3618 / 1966 CLASS A.) get a quote