Wear Mechanisms of TiB_2 and TiB_2-TiSi_2 at Fretting Contacts with Steel and WC-6 wt% Co

摘要

Unlubricated fretting wear tests on TiB_2 and TiB_2-5 wt% TiSi_2 ceramics against two different mating materials (bearing grade steel and WC-6wt% Co balls) were performed with a view to understand the counterbody-dependent difference in friction and wear properties. The fretting experiments were conducted systematically by varying load (2-10 N) at an oscillating frequency of 4 Hz and 100 μm linear stroke, for a duration of 100,000 cycles. Adhesion, abrasion, and three-body wear have been observed as mechanisms of material damage for both the TiB_2/steel and TiB_2/WC-Co tribosystems. The third body is predominantly characterized as tribochemical layer for TiB_2/steel and loose wear debris particles for TiB_2/WC-Co tribocou-ple. An explanation on differences in tribological properties has been provided in reference to the counterbody material as well as microstructure and mechanical properties of flat materials.