UNLUBRICATED WEAR AND FRICTION OF TOUGHENED ZIRCONIA CERAMICS AT ELEVATED-TEMPERATURES

The unlubricated friction and wear of toughened zirconia ceramics in contact with themselves and with metallic counterparts were investigated in air at temperatures up to 400-degrees-C. A pin-on-plate tribometer with reciprocating sliding motion was used to carry out the experiments. It was found that the temperature significantly influenced friction and wear characteristics of the tested pairs. The coefficients of friction in the range of 0.3-0.7 were found with the tendency to increase at elevated temperatures. Generally, severe pin wear was recorded with the higher wear rates at higher temperatures for metallic pins, and mostly lower wear for ceramic pins. Promising results were obtained for cast iron-ceramic pairs at room temperature and partially stabilized zirconia-partially stabilized zirconia pairs at 400-degrees-C, where the wear rates were in the range of 10(-6) mm3 m-1. The wear scars and wear debris were examined by scanning electron microscopy with an energy-dispersive X-ray attachment.