不同粒度SiC颗粒低温制备SiC泡沫陶瓷的性能

Properties of Silicon Carbide Foam Ceramics Prepared by Different Size of SiC Particles at Low Temperature

以SiC陶瓷前驱体聚碳硅烷(polycarbosilane,PCS)为粘结剂、SiC微粉为填料、聚氨酯海绵为模板,低温制备出了SiC泡沫陶瓷。研究了SiC颗粒粒度和PCS含量对SiC泡沫陶瓷线收缩率、体积密度、微观结构与抗弯强度的影响。确定了不同粒度SiC颗粒制备泡沫陶瓷的最佳烧成温度。结果表明,随SiC颗粒粒度与PCS含量的增加泡沫陶瓷的线收缩率增大、体积密度降低;泡沫陶瓷的抗弯强度随SiC颗粒粒度的增大而降低;颗粒粒度小于1μm时,最佳烧成温度为1200℃,颗粒粒度大于1μm时,最佳烧成温度为1100℃;PCS在1100℃与1200℃热解可得到β-SiC晶粒,其晶粒尺寸为12.2 nm与19.6 nm。

SiC foam ceramics were fabricated at low temperature,using polycarbosilane（PCS） as binder,SiC powder as filler,polyurethane as template.The effect of SiC particle size and PCS content on linear shrinkage,volume density,micro structures as well as flexural strength were studied.Optimal sintering temperature of SiC foam ceramics prepared by different size SiC particles was determined.Results show that the linear shrinkage of the SiC foam ceramics increases with PCS content and particle size,the volume density decreases with PCS content and particle size.The flexural strengths of the SiC foam ceramics decrease with particle size.When the particle size less than 1 μm,the optimal sintering temperature is 1200 ℃.When the particle size bigger than 1 μm,the optimal sintering temperature is 1100 ℃.β-SiC grains can be obtained by pyrolysis of PCS at 1100 ℃ or 1200 ℃,the grains size are 12.2 nm and 19.6 nm,respectively