硅橡胶/云母/氧化硅系热性能和陶瓷化机理

Thermal Property and Ceramic Mechanism ofSilicone/Mica/Silicone Oxide

摘要: 采用甲基乙烯基苯基硅橡胶为基体，添加成瓷填料云母粉、补强填料气相二氧化硅制备在高温下可形成自支撑陶瓷体的烧蚀材料。通过TG-DSC测试其在室温至1000℃过程中的热性能变化。并采用FTIR和XRD分析在不同温度下燃烧产物的成分组成及其变化。结果表明，当云母粉的添加量为40份时，在1000℃时残留率约为66.21%，在600℃以上成瓷填料与硅橡胶开始发生从有机相向无机相转变的陶瓷化反应，而且随着温度的升高，成瓷化程度逐渐加深。由此简述陶瓷化机理，硅橡胶分解产生的二氧化硅与云母粉发生反应，在填料边缘处形成起桥接作用的共熔混合物，冷却后形成陶瓷化产物。

Abstract: In this paper, methyl vinyl Phenyl Polysiloxane rubber (PVMQ) ablative composite filled with mica and silicone oxide was prepared. Its thermal properties were tested by TG-DSC analysis from room temperature to 1000˚C. After it was fired at different temperatures, the products were analyzed by Fourier transform infrared spectrometer and X-ray diffraction. The results showed that when the addition of mica was 40, the residual rate at 1000˚C was 66.21%. When the temperature was above 600˚C, the filler and organic silicon rubber started to transform from organic to inorganic. As temperature rose, the extent of porcelain was gradually deepened. So the ceramic mechanism of the composite could be described that the silicon oxide decomposed from silicon rubber reacted with mica. Then eutectic mixture which had a bridge effect was formed at the edge of fillers and the ceramic products were obtained when cooled down.