Abstract: To improve the alkali corrosion resistance of mullite-corundum saggars,mullite-corundum-magnesium aluminate spinel multiphase materials were prepared using coal gangue,industrial alumina,and industrial magnesia as raw materials via a two-step calcination method.Effects of the industrial magnesia addition (1%,2%,3%,4%,and 5%,by mass) on the phase composition,microstructure,and physical properties of the samples were studied.The corrosion resistance mechanism of the samples to sodium ion battery cathode materials was explored.The results show that:(1)MgO can promote the growth of mullite crystals and the sintering densification of the samples;due to the direct bonding of mullite crystals and the toughening of microcrystalline magnesium aluminate spinel particles,all samples have high cold compressive strength,≥248 MPa;(2)the MgAl₂O₄ spinel distributed in different forms in the samples can form physical barriers to prevent Na⁺ penetration,block its reaction with mullite and corundum,and improve the alkali corrosion resistance of the samples;(3)considering the physical properties and the alkali corrosion resistance of the samples,the optimum addition of the industrial magnesia is 4%.

Key words: mullite-corundum-magnesium aluminate spinel, phase composition, microstructure, alkali corrosion resistance

摘要： 为了提高莫来石-刚玉质匣钵的抗碱侵蚀性能,以煤矸石、工业氧化铝和工业氧化镁为原料,采用二步煅烧法制备了莫来石-刚玉-镁铝尖晶石复相材料,研究了工业氧化镁加入量(加入质量分数分别为1%、2%、3%、4%和5%)对试样物相组成、显微结构及物理性能的影响,并探究了试样抗钠离子电池正极材料的侵蚀机制。结果表明:1)氧化镁可促进莫来石晶体生长和试样烧结致密化,且由于莫来石晶体直接结合及微晶镁铝尖晶石颗粒增韧,所有试样均具有高的常温耐压强度,≥248 MPa;2)以不同形态分布于试样中的镁铝尖晶石可形成物理屏障,阻止Na⁺渗透,阻隔其与莫来石和刚玉反应,提高试样的抗碱侵蚀性能;3)综合试样的物理性能和抗碱侵蚀性能,工业氧化镁的最佳加入量为4%(w)。

关键词: 莫来石-刚玉-镁铝尖晶石, 物相组成, 显微结构, 抗碱侵蚀性能