The sintering behavior of zircon with silica was investigated. Zircon with 5 vol% of sedimentation SiO2 resulted in the apparent density of 4.45 g/cm3, the diametral tensile strength of 12.125 kgf/cm2, and the micro Vickers hardness of 1283 HV. The dissociation temperature and mechanical characteristics of the ZrSiO4 were changed with different kinds of SiO2. SiO2 addition prevented dissociation of ZrSiO4. Zircon with 5 vol% of sedimentation SiO2 and with 5 vol% of fused SiO2 resulted in increased diametral tensile strength and increased micro Vickers hardness by suppression of ZrSiO4 dissociation and low temperature liquid SiO2 formation. Zircon with fumed SiO2 and quartz SiO2 resulted in decreased diametral tensile strength and decreased micro Vickers hardness because of cristobalite and quartz phase formation and high temperature liquid SiO2 formation. Zircon with 10 vol% of SiO2 resulted in decreased diametral tensile strength and decreased micro Vickers hardness because of weak particle coupling due to excess formation of liquid SiO2.

Effect The effect of sintering additives (SiO2, Al2O3, Clay) on the mechanical characteristics of sintered zircon was investigated. 1 vol% of additives in zircon powder was was sintered at 120~1500˚C, the mechanical characteristics were measured, and microstructure analysis were was conducted. Al2O3 and clay additions increase the formation of monoclinic and tetragonal-ZrO2 formation. An addition of SiO2 addition suppressed the formation of tetragonal-ZrO2 formation., The A specimen sintered at 1400˚C showed the a density of 4.05 g/cm3 and the a microhardness of 1120 HV, respectively.