Mechanical properties of hot-pressed ZrO2 reinforced with (W,Ti)C and Al2O3 additions

Carbide, oxide and nitride-reinforced ceramic composites are usually accepted as a competitive technological option for cemented carbide (WC–Co). In recent years, these materials have been studied as reinforcement in ceramic composite systems with Al2O3 and ZrO2 as matrix. The present study reports on the mechanical results obtained from reinforcing ZrO2 with (W,Ti)C and Al2O3 particles. High-purity Y-TZP commercial zirconia were mixed with a fixed concentration of 30 wt.% of (W,Ti)C or Al2O3 and hot-pressed in argon atmosphere at 1650 °C under a pressure of 20 MPa for 30 min. The results indicated that the hot-pressing method produced dense samples with low porosity values. The X-ray diffraction pattern showed no formation of new crystalline phases between the matrix and the reinforcing elements. The addition of Al2O3 and (W,Ti)C particles leads to an increase in hardness of the sintered samples from 11.7 GPa to approximately 15.2 and 18.7 GPa, respectively. On the other hand, the presence of both particles did not significantly improve the fracture toughness of the ZrO2 ceramic matrix. These results suggest that ZrO2–(W,Ti)C composites obtained by uniaxial hot-pressing show great potential for use as machining-cutting tools, owing to their high hardness and good mechanical resistance.