Abrasive wear performance of zirconium diboride based ceramic composite

Abstract

The present study focuses on the wear behavior of a pressure-less sintered ZrB2–20 vol% SiC composite in dry sliding interaction against the electroplated diamond disc. Pressure-less sintering was carried out at 2000 °C for 2 h in an argon atmosphere. Sintered composite possesses 98% of the theoretical density, and primarily microstructure contains ZrB2 and SiC phases. The sliding wear of the investigated composite has been studied in pin-on-disc equipment at room temperature at different combinations of loads and sliding speeds to examine the influences of the test parameters on wear mechanism. The results show that the elastic modulus, hardness and fracture toughness for ZrB2 20 vol% SiC are 442 ± 4.5 GPa, 16.5 ± 0.5 GPa, and 5.67 MPa√m, respectively. Results also show that the specific wear rate of the ZrB2-SiC composite increases continuously with increasing the applied loads whereas, it decreases with increasing sliding speed. XRD analyses of worn surfaces suggest that the phase transformation from ZrB2 to ZrO2 may occur due to frictional heating during sliding. The specific wear rates are in the order of ~10−6–10−8 cm2/Nm. The post wear test characterization suggests that oxidation dominates mild wear with low roughness values at low load and high sliding speed, whereas at high loads and low sliding speed severe wear mechanism is observed with high roughness values and deep grooves in surfaces. The mixed mode (oxidative–grain pullout-micro-cutting) wear mechanism is controlling the severe wear.