ANALYSIS OF TRANSFER FILMS FORMED ON STEEL AND CO-WC DURING SLIDING AGAINST MOS2-COATED STEEL IN ARGON

MoS2-coated 52100 steel balls were slid against uncoated 52100 steel and Co-WC balls in dry argon at a speed of 0.2 m s-1 under moderately high stresses (greater than 1 GPa). The transfer films were examined by transmission electron microscopy, scanning Auger microscopy and scanning electron microscopy. Analysis revealed that the transfer film was predominately MoS2 oriented with its basal planes parallel to the surface. Other phases present in the transfer included Fe3O4 for 52100 steel and CoMoO3 for Co-WC balls. The 52100 steel was worn during sliding by the MoS2-coated 52100 ball while the harder Co-WC showed no wear. Co-WC reacted chemically with MoS2 as evidenced by the formation of CoMoO3. MoS2 coatings run against Co-WC had twice the endurance of MoS2 coatings run against steel. © 1990.