晶种对氢氧化铝转相和热压烧结氧化铝晶形变化的影响

Imfluence of α-Alumina Seeds on Transformation of Aluminium Hydroxide and Morphology of Alumina Grain in Hot-Pressing

以氢氧化铝为初始原料,通过球磨过程中高纯氧化铝磨介的磨屑作为晶种引入氢氧化铝中.引入的α-Al2O3品种使氢氧化铝于1100℃×2h的条件下转变为α相氧化铝.而且随着α-Al2O3品种引入量的增加,煅烧后氧化铝颗粒的平均粒径减小,颗粒尺寸分布均匀.煅烧得到的氧化铝超细粉经热压烧结后,Al2O3晶粒形貌随品种的引入量的不同而发生变化.未引入α-Al2O3品种的条件下,晶粒形状主要为等轴状;晶种引入后,晶粒发育成六角片状;而且随着晶种引入量进一步增加时,六角片状晶粒尺寸减小,当晶种数量增加到20wt％以上时,晶粒发育生长为长柱状.

Abrasives as seeds were introduced to the starting materials of aluminium hydroxide by wet-grinding of high-purity alumina milling balls. The phase transformation from aluminium hydroxide to α-Al2O3 was completed at 1100℃ for 2h by seeds added. The size of alumina particle derived from calcined aluminium hydroxide was reduced and narrow particle size distribution was obtained with increasing amount of the seeds. Alumina grain shapes changed with the amount of introduced seeds: equiaxed grains were observed for the samples without seeds introduction, hexagonal platelets were developed after seeds addition. Finally the grain shape showed a trend to elongated grains with seed concentration up to 20wt%.