制备工艺对新型陶瓷刚玉磨料显微结构的影响

Effect of preparation techniques on microstructure of new ceramic corundum abrasives

本文以硝酸铝和氨水为原料,添加少量无机添加剂,采用湿化学方法制备了Al2O3先驱体,再经干燥、烧结等热处理得到了新型陶瓷刚玉磨料。采用PHILIPSXL30型环境扫描电子显微镜对不同工艺制备的陶瓷刚玉磨料的显微结构进行了分析观察。探讨了合成工艺、添加剂引入方式和热处理时间对陶瓷刚玉磨料显微结构的影响。研究结果表明,合成工艺、添加剂引入方式和热处理时间均对磨料的显微结构有较大影响。溶胶-凝胶工艺相比共沉淀工艺更容易获得细晶、均匀的结构;添加剂采用固相方式引入而制备的磨料,其晶粒粗大,呈长柱状,而采用液相方式引入而制备的磨料晶粒细小,近等轴晶;对于同一种磨料,随着热处理时间的延长,晶粒由二维向三维的方向生长,并且时间的不当延长,可能导致晶粒的异常长大。

By taking Al（NO3）2 ·9H2O and NH3·H2O as raw materials, and with a slight amount of inorganic additives, Al2O3 precursors were prepared by wet chemical method. After drying and sintering of the Al2O3 precursors, a new kind of ceramic corundum abrasive grains was obtained. Microstructures of the new ceramic corundum abrasives were observed and analyzed by PHILIPSXL30 scanning electron microscope （SEM）. Effects of synthesis process, introducing method of the additives and heat - treatment time on the microstructures of the new ceramic corundum abrasives were investigated. The results showed that, Sol - gel synthesis process was beneficial to get fine - grained and uniform microstructured corundum abrasives compared with co-precipitation process; the abrasives grain size with additives introduced by solid method were coarse, their shapes were mostly cylindrical; while the grains of abrasives with additives introduced by liquid method were fine, and their shapes were approximate equiaxed ; grains grew from two - dimension to three - dimension with increasing of heat - treatment time, but it may induce abnormal grain growth if heat - treatment time was prolonged improperly.