环境湿度对电真空陶瓷性能的影响研究

Effect of Environment Humidity on Properties of Green Body of Vacuum Insulation Alumina Components

采用热压铸成型方法制备了氧化铝陶瓷坯体,研究了陶瓷坯体贮存环境湿度对陶瓷坯体流变性能、脱脂失重率和烧结收缩率的影响,并通过扫描电子显微镜对烧结后陶瓷的微观形貌进行了表征。研究结果表明,在湿度较大的贮存环境下,陶瓷坯体中氧化铝粉体吸附大气中水分,导致其流变性能改变,进而致使脱脂过程中氧化铝粉体流失现象增强,脱脂失重率增大,在陶瓷烧结后密度不变的情况下,导致陶瓷烧结收缩率呈现一定规律性变化。

The green-body of alumina ceramics,an insulation material for vacuum electronics device,was fabricated by low pressure injection molding. The effect of humidity on the properties of the green-body stored away in ambient environment,including the microstructures,rheological behavior,weight-loss ratio in removing binder and shrinkage ratio in sintering,was investigated with scanning electron microscopy and conventional tools. The results show that the environment humidity strongly affected the rheological behavior,but weakly influenced the microstructures and sintered density of the green-body. As the humidity increased,an increasing water-content,adsorbed by the highly porous green-body,decreased the grain-surfactant interfacial adhesion,resulting in a decreasing viscosity and an increasing yield point of bulk green-body; worse,such changes in the rheological properties accounted for the increases of outflow and weight-loss of alumina powder in binder removal,and shrinkage ratio in sintering.