MICROSTRUCTURE AND ELECTROCONDUCTIVITY OF TiN-Al2O3 COMPOSITES PREPARED BY HOT-PRESSING

After the addition of TiN into Al2O3 ceramic, the intensity, toughness and wear-resisting property of the ceramics increased, and the most important thing were the improvement of the electrical property. In this thesis, Al2O3-TiN composites were prepared by hot-pressing (HP) technique. And the SiO2 was added as sintering additives. The TiN powders homogenously distributed in the Al2O3 matrix. The ceramics have high mechanical properties: Vickers hardness could attain to 20GPa, and the highest was 25.5 GPa; fracture toughness was between 4 and 6 MPa·m, and flexural strength could reach 578 MPa. Electrical conductibility tests indicate that the electrical resistivity of TiN-Al2O3 ceramics descended with the increasing content of TiN from 5 to 20 vol.%, and the electrical resistivity were between 10Ω·cm to 10 Ω·cm. The highest on-load voltage of the ceramics could reach 5000 V, meanwhile the current was only 89 nA.