Abstract:
TiC ceramics were prepared by pressureless liquid phase sintering at 1 850 ℃. The effect of the mass fraction (0,6%, 8%,10%) of sintering additive Al
2O
3-Y
2O
3 (Al
2O
3 to Y
2O
3 molar ratio of 1.5) on the microstructure and properties of TiC ceramics was investigated. The results show that TiC phase, YAM (Y
4Al
2O
9) phase and YAG (Y
3Al
5O
12) phase existed in TiC ceramics after adding sintering additive. With increasing mass fraction of sintering additive from 0 to 10%, the relative density of ceramics increased from 94.50% to 97.86%, the open porosity decreased from 0.77% to 0.21%, the YAM and YAG phases increased and gradually aggregated, and the fracture toughness, Vickers hardness and flexural strength all increased first and then decreased. When the mass fraction of sintering additive was 6%, the fracture toughness and Vickers hardness reached the maximum value of 6.2 MPa·m
1/2 and 19 GPa, respectively. When the mass fraction of sintering additive was 8%, the flexural strength reached the maximum value of 524 MPa. The resistivity of ceramics was between 1.00×10
-6-2.00×10
-6 Ω·m, and the addition of sintering additives affected the electrical conductivity little.