HIGH-TEMPERATURE SOLID-LUBRICATED BEARING DEVELOPMENT - DRY POWDER-LUBRICATED TRACTION TESTING

As part of a high-temperature, dry-lubricated bearing technology and lubricant system development program, a high-speed and high-temperature disk-on-disk tribometer was utilized and a matrix of traction data covering a range of loads, speeds, and temperatures was obtained. An experimental investigation of powder-lubricated rolling and sliding contacts for three types of triboparticulates (NiO, TiO2, and ZnMoO2S2) was undertaken. The influence of dry triboparticulates on the traction coefficients between two ceramic materials (Si3N4 against itself) was investigated. The most important results of this investigation are characteristic curves for the traction coefficient versus the slide/roll ratio with dry powders which are reminiscent of fluids, and the observation that dry powder lubricants lower traction coefficients and wear. Measured tractions are found to be a strong function of powder lubricant type and values decrease with slide-to-roll ratio and load. The data show a weak sensitivity to temperature over the 70-degrees-F to 1200-degrees-F range.