Abstract: To improve their mechanical properties,MgO ceramic filters with porous skeleton structures were prepared by the organic foam impregnation method using microporous MgO powder as the raw material.The effects of the second-phase nano-alumina additions (0,3%,6%,9%,and 12%,by mass) and heat treatment temperatures (1 450,1 500,1 550,and 1 600 ℃) on the physical properties,phase composition,microstructure and mechanical properties of the ceramic filters were investigated.The results show that:the introduction of nano-alumina leads to the in-situ formation of magnesium aluminate spinel among the grains,which improves the grain bonding strength,reduces the apparent porosity,increases the bulk density and improves the cold compressive strength.However,when the nano-alumina addition exceeds 6%,excessive spinel among the grains hinders the direct bonding of MgO grains,thus reducing the cold compressive strength.The raise in the heat treatment temperature increases the solid solubility of Al₂O₃ in MgO,thereby promoting sintering,increasing the relative density,and enhancing the cold compressive strength.With the nano-alumina addition of 6% and heat treatment temperature of 1 600 ℃,the filter exhibits the maximum cold compressive strength of 1.42 MPa,the apparent porosity of 81.5%,and the bulk density of 0.66 g·cm^-3.

Key words: MgO, nano-alumina, ceramic filters, cold compressive strength

摘要： 为了提高MgO陶瓷过滤器的力学性能,采用有机泡沫浸渍法,以微孔MgO粉体为原料制备含多孔骨架结构的MgO陶瓷过滤器。探究了第二相纳米氧化铝添加量(添加质量分数分别为0、3%、6%、9%和12%)和热处理温度(1 450、1 500、1 550和1 600 ℃)对陶瓷过滤器物理性能、物相组成、显微结构和力学性能的影响。结果表明:引入纳米氧化铝在晶间原位形成镁铝尖晶石,提高了晶粒间的结合强度,降低了显气孔率,增加了体积密度,提高了室温压缩强度;但当纳米氧化铝添加量超过6%(w)时,过量的晶间尖晶石反而阻碍了MgO晶粒的直接结合,从而降低了室温压缩强度;热处理温度的升高增加了Al₂O₃在MgO中的固溶度,促进烧结提高了致密度和室温压缩强度;当纳米氧化铝添加量为6%(w),热处理温度为1 600 ℃时,MgO陶瓷过滤器的室温压缩强度达到最大值,为1.42 MPa,显气孔率为81.5%,体积密度为0.66 g·cm^-3。

关键词: MgO, 纳米氧化铝, 陶瓷过滤器, 室温压缩强度