粒径及成型压力对α氧化铝粉体烧结行为的影响

Effect of Particle Size and Forming Pressure on Sintering Behavior ofα-Al2O3 Powders

以D50为0.171μm和0.432μm的α氧化铝粉为原料,采用不同的成型压力制得生坯,并在1450℃进行烧结,研究了粉体粒径和成型压力对α氧化铝粉体烧结行为的影响.D50为0.432μm的粉体,烧结活性较差,成型压力从100 MPa提升到300 MPa,生坯相对密度从54.1%增加到56.6%,烧结体相对密度从93.2%增加到94.9%.D50为0.171μm的粉体,烧结活性较好,成型压力从100 MPa提升到300 MPa,生坯相对密度从51.3%增加到53.8%,但烧结体密度始终在98.6%~98.8%之间,并未产生大的变化.结果表明,提升成型压力对Al2O3粉体烧结行为影响有限,减小粉体粒径、提高粉体烧结活性,才是提高Al2O3陶瓷密度、降低烧结温度的关键.

α-Al2O3 powders with D50 of 0.171 μm and 0.432 μm were used as raw materials, the green bodies were prepared under various forming pressures and sintered at 1 450 ℃. The effects of particle size and forming pressure on the sintering behavior of α-Al2O3 powders were studied. α-Al2O3 powder with D50 of 0.432 μm exhibited low sintering activity. The relative density of its green body increased from 54.1% to 56.6%, and the relative density of sintered body increased from 93.2% to 94.9%, when the forming pressure increased from 100 MPa to 300 MPa. α-Al2O3 powder with D50 of 0.171μm exhibited high sintering activity, when the forming pressure increased from100 MPa to300 MPa. The relative density of its green body increased from 51.3% to 53.8%, but the relative density of sintered body maintained between 98.6%~98.8%. The results showed that improving the forming pressure had limited influence on sintering performance of α-Al2O3 powders. Reducing the particle size and improving the sintering activity was the key factors to increase sintering density and reduce sintering temperature of Al2O3 ceramic.