Research on the Influence of Sintering Temperature on the Properties of SiC-Al2O3-Y2O3-MgO Ceramics
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(tanδ around 0.006).It is a silicon carbide composite ceramic material that has a dense and high hardness.
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