Tribological reaction generated on ceramic-stellite couples under dry sliding contact and water- and oil-lubricated conditions

Alloy-to-ceramic wear experiments were carried out on a wear test machine using a vane-disk adapter in which the disk specimen was pressed against three stationary vanes. This setup was employed to test the frictional contacts between the Stellite coating of the disk and the Si₃N₄ material of the vanes. The effect of applied load and sliding speed on tribological behavior is evaluated according to the tribological parameters of wear volume friction coefficient, wear mechanism and the oxides generated during wear processes. The lubrication results associated with water and oil lubrications show the wear volume to be indeed lower as compared with the dry sliding, contact, especially for the tribosurface lubricated by oil. A thicker and uniformly distributed transferred layer which was present in dry sliding contact results in a great wear loss. Since the debris is thickly covered with oxides the silicon nitride lubrication is due to the oil entrapped in fracture pits, and allows the wear loss and friction coefficient in oil lubrication to be much lower.