A Manufacturing Process of ZrO_2-Ca from ZrSiO_4 under a Reduction Environmental Condition

摘要

ZrO_2-Ca is a solid solution used as a functional ceramic, because of its existing of oxygen vacancy. As known, molten salt of ZrSiO_4 could decompose into tetragonal ZrO_2 and SiO_2 with β -cristobalite structure at above 1670℃. And then, recrystaliization occurs when it's cooling to ambient environment at room temperature. After adding CaO and CaCl_2, into molten salts of ZrSiO_4, they can decompose at lower temperature of 750℃ ～ 800℃- Because of its eutectic point can make the decomposition temperature decrease, the high-temperature cubic and tetragonal ZrO_2 polymorphs can be stabilized at lower temperature by the doping of Ca. Therefore we can get stabilized ZrO_2-Ca at 800℃ as reported in the previous work. In this paper, we utilize a reduced atmospheric environment within a graphitization furnace, silicide will be get rid by forming gas directly. Thus a new manufacturing process could enhance the full decomposition of zircon into zirconia product from above 950℃ to the higher temperature 1250℃ under the reduction atmospheric condition. It is expected that the quality of ZrO_2 will be better than that was synthesized during in conventional thermal treatment. Their experimental results will be discussed hereafter in this meeting.