Effects of SiO_2 and ZrO_2 Additives on Microstructure and Properties of AI_2O_3 Ceramic

摘要

Alumina ceramic, with high mechanical strength, good electric insulation, high hardness and good corrosion resistance performance, has been widely used in machinery, electronic and electrical, chemical, medicine, construction and other high-tech areas. In this study, both silicon sol and zirconia particles are incorporated into the system and dense alumina composite ceramics were prepared by cold isostatic processing and pressureless sintering at 1550 ℃. The influence of additives on phase composition, microstructure and mechanical properties were investigated. The XRD results show that mullite phase was generated in the composite ceramic. The composite ceramic has excellent comprehensive performance. For example, the sample with 3wt.% SiO_2 and 5wt.% ZrO_2 has density of 3.87g·cm~(-3), Vickers hardness of 17.6GPa, flexural strength of 369.0MPa, young's modulus of 374.2GPa and fracture toughness of 3.57MPam~(1/2).