摘要
以分析纯的MgO、活性α-Al2O3、电熔单斜锆为原料,采用淬冷法研究了Mg5+x Al2.4–x Zr1.7+0.25x O12(–0.4≤x≤0.4)的化学组成、热处理温度对合成MgO–MgAl2O4–ZrO2系三元化合物的影响,并对其合成机理进行了分析。结果表明:当温度低于1 650℃时,主要为MgAl2O4的形成及其晶粒长大过程;当温度高于1 650℃时,MgO与ZrO2向MgAl2O4扩散,反应形成了Mg4.68Al2.64Zr1.68O12;当温度为1 740℃时,Mg4.68Al2.64Zr1.68O12的合成趋于完全,其合成率达到89.5%,残留的MgAl2O4和ZrO2主要分布在Mg4.68Al2.64Zr1.68O12晶内;在合成温度为1 760℃、x=–0.2条件下,Mg4.68Al2.64Zr1.68O12的合成率最大,高达89.99%,且其晶粒发育最为完善;Mg4.68Al2.64Zr1.68O12在低温下分解成MgO、MgAl2O4和C-ZrO2共析体,实现了MgAl2O4和ZrO2的高度分散。
The effects of the chemical composition of Mg5＋xAl2.4-xZr1.7＋0.25xO12 （-0.4≤x≤0.4） and heat treatment temperature both on the MgO-MgAl2O4-ZrO2 system ternary compound prepared with analytically pure MgO, activeα-Al2O3 and fused m-ZrO2 as raw materials were investigated, and the synthesis mechanism of the compound was analyzed. The results show that MgAl2O4 is formed via the reaction of MgO with Al2O3 and its grain grows gradually at a temperature of〈1 650℃. Mg4.68Al2.64Zr1.68O12 is formed via the diffusion reaction from MgO and ZrO2 to MgAl2O4 at〉1 650℃. Mg4.68Al2.64Zr1.68O12 can be synthesized completely and its synthesis rate is 89.5%at 1 740℃. The residual MgAl2O4 and ZrO2 are distributed in the intragranular of Mg4.68Al2.64Zr1.68O12. When x value is-0.2 at 1 760℃, the synthesis rate of Mg4.68Al2.64Zr1.68O12 is 89.99%, and its grain growth becomes complete. Mg4.68Al2.64Zr1.68O12 is decomposed to eutectoid of MgO, MgAl2O4 and ZrO2 at a low temperature, which can favor the dispersion of MgAl2O4 and ZrO2.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2013年第9期1271-1277,共7页
Journal of The Chinese Ceramic Society
关键词
氧化镁
镁铝尖晶石
氧化锆
镁铝锆化合物
合成机理
magnesium oxide
magnesium aluminate
zirconia
magnesium aluminum zirconium
synthesis mechanism
