助烧剂对微晶Al_(2)O_(3)刚玉磨料结构与性能的影响

Effect of Sintering Aids on Structure and Properties of Microcrystalline Al_(2)O_(3) Corundum Abrasives

采用溶胶-凝胶技术合成Al_(2)O_(3)刚玉前驱体,以SiO 2-MgO-CaO为烧结助剂,利用无压烧结技术制备微晶陶瓷刚玉磨料。研究了助烧剂成分、掺杂量对磨料微观结构和力学性能的影响。结果表明:MgO有助于片状晶的生成,CaO有助于等轴晶的生成,助烧剂成分的最佳物质的量比为n(SiO_(2))∶n(MgO)∶n(CaO)=2∶1∶2。晶粒尺寸随助烧剂掺杂量的增多而增大,单颗粒抗压强度和密度则先增大后减小,在掺杂量(质量分数)为2.0%时分别达到最大值43.6 N和3.92 g/cm^(3)。

Al_(2)O_(3)corundum precursor was synthesized by sol-gel technology.Microcrystalline Al_(2)O_(3)corundum abrasive was prepared by pressureless sintering with SiO_(2)-MgO-CaO as sintering aids.The effects of composition and doping amount of the sintering aids on microstructure and mechanical properties of the abrasive were studied.The results show that MgO contributes to the formation of plate-like grains and CaO contributes to the formation of equiaxed grains.The optimum ratio of sintering aids is n(SiO_(2))∶n(MgO)∶n(CaO)=2∶1∶2.The grain size increases with the increase doping amount of sintering aids,and the single particle compressive strength and density first increase and then decrease,reaching to the maximum value of 43.6 N and 3.92 g/cm^(3),respectively,when the addition amount of 2.0%.