高压烧结高纯微晶氧化铝陶瓷

以商业生产的高纯纳米α-Al2O3粉(99.9%,质量分数)、分析纯Mg(NO3)2为原料,以两面顶压机高压烧结,制备了纯Al2O3陶瓷及微量MgO掺杂的Al2O3陶瓷,并进行了密度测试与显微结构分析.与常压烧结相比,高压烧结可显著降低高纯Al2O3陶瓷的烧结温度,提高传质速率,大幅度缩短烧结时间,达到快速、低温烧结的效果.与常压烧结明显不同,在高压烧结时,MgO对高纯AlO3陶瓷的烧结致密化几乎没有影响.在4.5GPa,100 ℃高压烧结30 min,制备的纯Al2O3陶瓷的相对密度为97.65%,微量MgO掺杂的Al2O3陶瓷的相对密度达97.93%、平均晶粒尺寸约为4 μm.

HIGH-PRESSURE SINTERING OF MICROCRYSTALLINE AND HIGHLY PURIFIED ALUMINA CERAMIC

Pure Al2O3 ceramic and MgO-doped Al2O3 ceramic were prepared by high-pressure sintering, using a commercially available alpha-alumina nanopowder with a purity of 99.9% in mass and Mg(NO3)2 (analytical reagent) as the starting materials. These ceramics were characterized by density measurement and microstructure analysis. The sintering temperature of the highly purified Al2O3 ceramic decreases remarkably in the high-pressure sintering, as compared with the normal-pressure sintering, and the velocity of mass transfer also enhances, which shortens the sintering time. The high-pressure sintering can achieve fast- and low-temperature sintering. MgO has no effect on the densification of the highly purified Al2O3 ceramic in the high-pressure sintering process, which is obviously different than that in the normal sintering. The pure Al2O3 ceramic, with a relative density of 97.65%, and MgO-doped Al2O3 ceramic, with a relative density of 97.93% and an average grain size of 4 μm, were obtained by sintering for 30 minutes under a pressure of 4.5 GPa and a temperature as low as 1 100 ℃.