TRACTION CHARACTERISTICS OF HIGH-TEMPERATURE POWDER-LUBRICATED CERAMICS (SI3N4/ALPHA-SIC)

As part of a high-temperature, dry-lubricated bearing technology and lubricant system development program, a high-speed, high-temperature disk-on-disk tribometer was utilized and a matrix of traction data covering a range of load, speed and temperature was obtained. The influence of dry powder lubricants, TiO2 and MoS2, on the traction coefficients between two ceramic materials, Si3N4 and SiC, was investigated. The most important results of this investigation are characteristic curves for the traction coefficient vs. the slide/roll ratio with dry powders which are reminiscent of fluids, and the observation of dry powder lubricants' lower traction coefficients and wear. Measured tractions are found to be a strong function of powder lubricant type and values decrease moderately with slide-to-roll ratio and load. The data show a weak sensitivity to temperature.