微波烧结氧化铝陶瓷的纳米增韧研究

Nano-toughening of alumina ceramic by microwave sintering

高纯度氧化铝陶瓷具有极高的机械强度,在航空航天等国防尖端技术领域具有极好的应用前景.针对目前采用普通方法烧结的高纯度氧化铝陶瓷韧性较差的问题,利用圆柱形微波多模烧结腔进行了高纯度氧化铝陶瓷的纳米增韧研究.以氧化铝(质量分数99.9%)、氧化镁(质量分数0.05%)和氧化钇(质量分数0.05%)为基准原料配比,在其中添加不同比例的纳米氧化铝粉末,研究不同比例纳米氧化铝粉末对陶瓷性能的影响.结果表明,当纳米氧化铝粉末添加量达到30%时,高纯度氧化铝陶瓷试样的密度、维氏硬度和断裂韧性分别达到3.92g/cm3、23.2GPa和4.21Pa.m1/2;与未添加纳米氧化铝粉末烧结得到的陶瓷试样相比,密度降低0.5%,但其维氏硬度增加了2.2%,断裂韧性甚至增强了33.7%.

High purity alumina ceramic has bright application prospect in advanced national defense technology fields of aeronautics and astronautics because of its high mechanical strength. Ordinary sintered high purity alumina ceramic has poor toughness, so it＇s necessary to find out efficient methods to enhance its toughness. Nano-toughening of high purity Al2O3 ceramic was carried out in multi-mode cylindrical microwave sintering resonant cavity. The influence of nano-crystalline Al2O3 powder on the properties of sintered ceramic was researched by adding different amount of nano-crystalline Al2O3 powder into Al2O3（99.9 wt.%）,MgO（0.05wt.%）,Y2O3（0.05wt.%）mixture. Results show that the density, vickers hardness and fracture toughness of sintered Al2O3 ceramic reaches 3. 92 g/eraa, 23.2 GPa and 4. 21 Pa . m^1/2 respectively when the addition of nano-crystalline A1203 powder is 30wt. %. Compared with no nano-erystalline Al2O3 powder addition, the density reduces 0. 5%, vickers hardness increases 2.2% while fracture toughness enhances 33.7%.