Preparation And Properties Of Al₂O₃/Cu Composite Ceramic

Although alumina which has high melting point, high hardness, corrosion resistance, cheap, and many other advantages is widely used, the high sintering temperature and the brittleness limits its wide application in engineering. Therefore, how to improve the brittleness of alumina and the sintering temperature reduced is the key of Alumina Ceramics Research.In this paper, titanium oxide and silicon oxide were added as sintering additives. Copper as the second phase was mixed in alumina to prepare alumina/copper composite ceramic materials. The microstructure and performance of the materials were analyzed. The effect of titanium oxide and silicon oxide on microstructure and performance of alumina were researched. Alumina/copper composite powder was prepared by the method of non-uniform precipitation and the preparation of alumina/copper composite ceramic materials which were added sintering additives was accomplished. Scanning electron microscope, XRD, differential thermal-thermo gravimetric analysis were utilized to testing and characterization of samples.The results show that:when the titanium oxide content was 0.3wt.%and silicon oxide content was 0.4wt.%, the highest density of ceramic materials were obtained.With the effect of additives, the highest density which were respectively 3.87g/cm3 and 3.71g/cm3 increased by 8.1%and 7.8%,compared with the same conditions of alumina ceramics. This was due to the formation of solid solution and lattice activation when titanium oxide was added in alumina and the existence of liquid phase promoting sintering when silicon oxide was added in alumina. The micrographs indicated that the copper as the typical intergranular nano-crystalline was distributed in grain surface of alumina, 10nm, and strengthened alumina grain boundaries.When the copper content was 10wt.%, the density of alumina/copper composite ceramics was 3.98 g/cm3, and the toughening effect is the best. The increase of toughness is due to crack deflection and bridging caused by the addition of sintering additives and copper.