富铝尖晶石中刚玉的析晶与固溶

Solid solution and precipitation of corundum in alumina-rich spinel

以w(Al2O3)=84.4%的富铝尖晶石和α-Al2O3微粉为原料,制备了纯富铝尖晶石试样和加入10%(w)α-Al2O3微粉的富铝尖晶石-刚玉试样,分别在1 300、1 500、1 600和1 650℃保温4 h热处理1次,纯富铝尖晶石试样还在1 650℃保温4 h条件下反复热处理5次,然后进行XRD分析,以研究热处理温度和热处理次数对刚玉在这两种试样中向富铝尖晶石中固溶以及从富铝尖晶石中析出的影响。结果表明:1)在1 300、1 500和1 600℃保温4 h热处理1次后,纯富铝尖晶石试样中析出的刚玉量(w)分别为5%、15%、10%,而富铝尖晶石-刚玉试样中新析出的刚玉量(w)分别为10%、20%、13%,表明加入α-Al2O3促进了刚玉的析出;但在1 650℃保温4 h热处理1次后,纯富铝尖晶石试样没有析出刚玉,而富铝尖晶石-刚玉试样不但没有析出刚玉,而且具有较强的固溶刚玉的潜能。2)纯富铝尖晶石试样在1 650℃热处理5次后析出的刚玉量约为10%(w)。3)刚玉固溶入富铝尖晶石中会阻碍富铝尖晶石材料的烧结。

Alumina-rich spinel specimens and alumina-rich spinel/corundum specimens with 10 mass% （ similarly hereinafter） α-Al2O3 micropowder were prepared using alumina-rich spinel with 84.4% Al2O3, and α-Al2O3 micropowder as starting materials. Two kinds of specimens were fired one time at 1 300, 1500, 1 600 and 1650℃ for 4 h,respectively. Other alumina-rich spinel specimens were fired five times at 1650℃ for 4 h. Influences of firing temperatures and times on corundum solid solving into/precipitating from alu- mina-rich spinel were studied by XRD. The results show that： （ 1 ）after firing at 1 300,1 500 and 1600 ℃ for one time,respectively,the amounts of corundum precipitating from alumina-rich spinel specimens are 5%. 15%,and 10%, and those from alumina-rich spinel/corundum specimens are 10%, 20%, 13%,which means α-Al2O3 micropowder can promote the precipitation of corundum：but after firing at 1 650℃ for one time,corundum phase can not be found in the two kinds of specimens,and alumina-rich spinel/corundum specimen has strong potential to solid solve the corundum;（2）after firing at 1 650℃ for five times,the precipitated corundum amount is about 10% ;（3）the solid solution of corundum hinders the sintering of alumina-rich spinel material.