Manufacture And Properties Of The Al₂O₃-based Ceramics

Al2O3-based ceramics are essential structural materials, which have been widely used as cutting tools, because of their high strength, hardness, chemical stability and excellent wear resistance. But lower fracture toughness limits their applications. TiC ha a high melting temperature and high resistance to corrosion and oxidation. Since the addition of TiC to the AI2O3 matrix can increase some mechanical properties, the properties of TiC particles reinforced Al2O3-based ceramics were widely studied.The common method used to fabricate the Al2O3-TiC ceramics is to add TiC particles directly into Al2O3 matrix by ball milling. Preparation of Al2O3-based ceramics by HP attracts more attention. Conventional hot-pressing of Al2O3-based ceramics is carried out at 1650~ 1750C and 30 MPa for 1 h under argon atmosphere in an hot-pressing furnace.Al2O3-TiC ceramics with various size of starting powders were hot pressing using 30 wt.% TiC content. The Vickers hardness, bending strength and fracture toughness were studied. The experiment results show that the starting powders size has a significant effect on the properties of Al2O3-TiC ceramics. The Al2O3-TiC ceramics with various additions of TiC, from 15 to 35 wt.%, were manufactured. The effects of TiC particles on.the mechanical properties were studied. The experimental results show that the Al2O3-TiC ceramic with a content of 30 wt.% TiC content has the best mechanical properties. In the present study, Y2O3 was introduced into Al2O3-TiC ceramics. The experiments show that the additions of Y2O3 is effective in the densification of Al2O3-TiC ceramics with 0.35 wt.% Y2O3 content and the additions of > 0.35 wt.% Y2O3 is observed to be harmful.