Tribological properties of MoSi2-MoS2 coatings coupling with SAE 52100 steel under reciprocating sliding

Tribological properties of MoSi2-MoS2 coatings coupling with SAE52100 steel were tested under reciprocating sliding. Effects of normal load, sliding s peed and MoS2 content on the coatings tribological properties were studied. Worn surfaces of the coatings were analyzed by scanning electron microscop y (SEM) and X-ray photoelectron spectroscopy (XPS). The friction coefficien t of the coatings was approximately 0.45 and a little lower than that of th e monolithic MoSi2 The friction did not vary with the sliding time, sliding speed and load. Coating with 12 wt.% MoS2 had the lowest friction. Wear ra te of the coatings increased with the sliding speed and normal load and was higher than that of the monolithic MoSi2. Wear rate of the coatings did no t vary with MoS2 content. Worn surface of the coatings and the coupling ste el ball was covered by a SiO2 and MoO3 wear debris layer. Wear mechanism of the coatings was microfracture. (C) 2001 Elsevier Science B.V. All rights reserved.