烧结温度对SiC-Al_(2)O_(3)-Y_(2)O_(3)-MgO陶瓷性能影响的研究

Research on the Influence of Sintering Temperature on the Properties of SiC-Al_(2)O_(3)-Y_(2)O_(3)-MgO Ceramics

采用X射线衍射仪、扫描电子显微镜和硬度计研究了烧结助剂在最佳烧结温度下对SiC陶瓷的结构、形貌和性能的影响。结果表明:采用无压液相烧结合成SiC复合陶瓷,样品颗粒较为均匀,随着烧结温度的升高,样品的质量损失,气孔率和线收缩率均增加,而硬度先增加后减小。当烧结温度为1850℃时,陶瓷的硬度最高为30.4 GPa,热膨胀系数为3.68×10^(-6)/℃(室温至500℃温区范围内),最接近单晶硅的热膨胀系数(3.5×10^(-6)/℃),介电常数约为24.63,介电损耗最低,tanδ约为0.006,是一种致密性好,硬度高的碳化硅复合陶瓷材料。

The influence of sintering additives on the structure,morphology and properties of SiC ceramics at the optimum sintering temperature was investigated using X-ray diffractometer,scanning electron microscope,and hardness tester.The results show that the SiC composite ceramics are synthesized by pressureless liquid phase sintering,resulting in uniform particle distribution.As the sintering temperature increased,the samples exhibited increased mass loss,gas hole ratio,and linear shrinkage ration,while the hardness first increased and then decreased.When the temperature is 1850℃,ceramic exhibited the highest hardness of 30.4 GPa,and a thermal expansion coefficient of 3.68×10^(-6)/℃(within the temperature range from room temperature to 500℃),which is closest to the thermal expansion coefficient of single crystal silicon(3.5×10^(-6)/℃).The dielectric constant was approximately 24.63,with minimal dielectric loss(tanδaround 0.006).It is a silicon carbide composite ceramic material that has a dense and high hardness.