EFFECT OF MOLYBDENUM DITHIOCARBAMATE AND ZINC DITHIOPHOSPHATE ON THE TRIBOLOGICAL BEHAVIOR OF SI3N4 AND AL2O3

The effect of antiwear additives on the tribological behavior of Si3N4 and Al2O3 in sliding contact with cast iron was investigated under bo undary lubrication using a reciprocating wear tester. The beneficial e ffect of oil containing molybdenum dithiocarbamate (MoDTC) was observe d for the cast iron/Si3N4 pair. Specific wear rates of cast iron teste d against Si3N4 with oil containing MoDTC were lower than those of cas t iron tested against 52100 steel. The reduced specific wear rates wer e due to the formation of thick MoS2 film at the contact area, which w as identified by X-ray photoelectron spectroscopy (XPS) and Auger elec tron spectroscopy (AES). Oil containing zinc dithiophosphate (ZDP) did not decrease specific wear rates of the cast iron/Si3N4 pair compared to those of cast iron/52100 steel pair. The specific wear rates of ca st iron tested against Al2O3 were higher compared to those of cast iro n tested against 52100 steel regardless of the lubricants used.