Influence of contact geometry on friction characteristics of MoDTC under sliding conditions

摘要

The influence of contact surface conditions on the sliding and friction characteristics of MoDTC-added oils was determined by using a reciprocating motion type friction tester. When determining the effect of the contact geometry under constant load and temperature conditions, it was found that the coefficient of friction at the linear contact was lower than that at the point contact, and the difference between them grew larger with an increase of applied load or a rise of temperature. At the point contact, adhesion proceeded intensively with repeated friction and the coefficient of friction and the wear volume increased with a temperature rise and an increase in the applied load. On the other hand, at the linear contact, the smoothing of the surface asperity with repeated friction took place and the formation of Mo compounds under improved lubrication and asperity smoothing conditions promoted the reduction of the coefficient of friction. Then, the plotting of the coefficient of friction against the average Hertzian pressure showed that data obtained at the linear contact had a lower pressure and those obtained at the point contact had a higher pressure. When a certain contact pressure was exceeded the curve for each temperature level showed a sharp slope and data distributed on the right-hand line.