不同氧化铝对轻量微孔刚玉骨料结构与性能的影响

Effect of different Al_2O_3 on microstructure and properties of lightweight microporous corundum aggregates

以α-Al2O3微粉、工业Al2O3细粉为原料,经过湿磨制料和1 830℃烧结制备了轻量微孔刚玉骨料,研究不同氧化铝原料对轻量微孔刚玉骨料体积密度、气孔率及显微结构的影响。结果表明,在实验工艺条件下,采用工业氧化铝细粉或α-Al2O3微粉作为原料,均可获得体积密度为3.2～3.5g/cm3、显气孔率在5%以下、平均孔径为0.5～1μm的轻量微孔刚玉骨料,其800℃导热系数比普通板状刚玉小25%～42%;相比之下,采用工业Al2O3细粉作为原料时,所制得的骨料晶粒粗大,体积密度较大,闭口气孔在总气孔中所占比率较小,而采用α-Al2O3微粉作为原料时,所制得骨料晶粒细小,体积密度较小,闭口气孔在总气孔中所占比率较大,平均气孔孔径及导热系数亦比采用工业Al2O3细粉作原料时更小。

Lightweight microporous corundum aggregates were prepared by wet grinding process using α-Al2O3 micropower and industrial Al2O3 power as main starting materials,and the influences of different alumina on bulk density,porosity and microstructure fired at 1 830 ℃ were researched.The results show that,under the experimental conditions,it is possible to obtain the lightweight microporous corundum aggregates with the bulk density between 3.2~3.5 g/cm3,apparent porosity under 5% and average pore size between 0.5~1 μm,no matter whether α-Al2O3 micropower or industrial Al2O3 power is used,whose thermal conductivity measured at 800 ℃ is 25%~42% smaller than that of ordinary tabular corundum.When industrial Al2O3 power is used as the main starting material,the aggregate obtained has bigger grains,bigger bulk density and smaller closed porosity in the total porosity.But when α-Al2O3 micropower is used as the main starting material,the aggregate obtained has finer grain,smaller bulk density,more closed porosity in the total porosity,smaller average pore size,and smaller thermal conductivity.