Tribological behaviour and wear mechanisms of manganese phosphate coatings under dry reciprocating sliding contact conditions

The aim of the present work is to understand the reciprocating sliding friction and wear behaviour of manganese phosphate coatings that are deposited onto mild steel substrates by a wet-chemical process. All tribological tests were performed under dry conditions with a translatory oscillation tribometer for up to 500 oscillating cycles with contact pressures from 750 to 2000 MPa on three materials: (a) uncoated substrate (1.0037 mild steel), (b) manganese phosphate (Mn-P) and (c) manganese phosphate coated with prior activation (A & Mn-P) using steel ball as a counterpart. A significant difference in the frictional performance among the two different phosphate coatings was not seen. Nevertheless, the two different phosphate coatings showed diverse wear mechanisms compared to mild steel.