中文摘要：

采用冷坩埚法制备α-Al2O3多晶料,研究了引燃剂的形态、坩埚下降的速率、加料速率等工艺参数变化对所成形晶碇质量的影响。结果表明：采用的引燃剂为高纯铝片,坩埚下降速率为10 mm/h,采取加料速率为1 kg/min的最佳工艺条件,可制备出高致密度、高纯度的α-Al2O3多晶料。采用排水法测密度,用电感耦合等离子体原子发射光谱仪（ICP-OES）对原料粉和多晶块料中Ca、Fe、Na、Mg、K、Ti、Si、Cr等元素进行测定。结果表明：多晶块料中白色可用部分Ca、Fe、Na、K、Ti、Si、Cr等元素明显降低,说明采用冷坩埚法制备的氧化铝多晶料对原料粉具有一定的提纯作用,并且测量其堆积密度为2.6～2.8 g/cm3。因此采用冷坩埚法制备的α-Al2O3多晶料符合目前生长大尺寸蓝宝石对原料的要求。

英文摘要：

Polycrystalline α-Al2O3 materials were prepared by cold crucible method.The effects of the ignition agents,the withdrawal velocity,the feeding rate and other process parameters on the quality of crystallization were investigated.The results showed that the optimum conditions for preparing high-density,high-purity polycrystalline α-Al2O3 materials as followed： high-purity aluminum flakes as ignition agents,withdrawal velocity rate in 10 mm/h and feeding rate in 1 kg/min.The density of samples is tested by draining method,the impurities concentrations of Ca,Fe,Na,Mg,K,Ti,Si and Cr in raw powder and polycrystalline α-Al2O3 materials prepared by cold crucible are analyzed by ICP-OES.The concentrations of impurities in polycrystalline α-Al2O3 materials can be decreased comparison with in raw powder,which shows that it is an effective method for the removal of impurities.The bulk density of polycrystalline α-Al2O3 is 2.6-2.8 g/cm3.Polycrystalline α-Al2O3 materials prepared by cold crucible meet the current growth of large-size sapphire for raw materials requirements.