Effect of TiO2 on sinterability and physical properties of pressureless sintered Ti3AlC2 ceramics

TiO2 was selected as effective sintering aid for pressureless sintering of Ti3AlC2 ceramics in this study. The addition of only 5 wt% TiO2 largely promotes the densification and nearly dense Ti3AlC2 ceramic was obtained by pressureless sintering at 1500 degrees C. Significant strengthening and toughening effects were observed with the addition of TiO2. High Vickers hardness, flexural strength and fracture toughness of 3.22 GPa, 298 MPa and 6.2 MPa m(-1/2), respectively, were achieved in specimen pressureless sintered with 10 wt% TiO2. Additionally, the addition of 5 wt% TiO2 had no deleterious effect on the excellent oxidation resistance of Ti3AlC2 ceramic under 1200 degrees C water vapor atmosphere, while addition of 10 wt% TiO2 accelerates the oxidation rate by two orders of degree.