TRIBOLOGY STUDY OF NOVEL Ti_3SiC_2 MATRIX COMPOSITES REINFORCED WITH CERAMICS (Al_2O_3, BN, B_4C) PARTICULATES

摘要

This paper reports the synthesis of Ti_3SiC_2 matrix composites by incorporating (1 and 6 vol%) Al_2O_3, (1 and 5 vol%) BN, and (1 and 5 vol%) B_4C ceramics particulate additives in the Ti_3SiC_2 matrix. All the composites were fabricated by pressureless sintering by using ~1 wt% Ni as a sintering agent at 1550 °C for 2h. SEM and XRD studies showed that Al_2O_3 is relatively inert in the Ti_3SiC_2 matrix whereas BN and B_4C reacted significantly with the Ti_3SiC_2 matrix to form TiB_2. Detailed tribological studies showed that Ti_3SiC_2-lwt%Ni (baseline) samples showed dual type tribological behavior where the friction coefficient (u) was low (p ~0.2) during stage 1, thereafter p increased sharply and transitioned into stage 2 (μ -0.8). The addition of Al_2O_3 as an additive had no effect on the tribological behavior, but the addition of B_4C and BN was able to enhance the tribological behavior by increasing the transition distance (TD). For example, the TD of Ti_3SiC_2-lwt% Ni was -10 m and TD increased to -90 m and -150 m in 312Si-5%B_4C and 312Si-5%BN, respectively.