致密SiC包覆层低温流化床化学气相沉积制备及形成机制

Low temperature synthesis and formation mechanism of dense SiC coating layer by fluidized bed chemical vapor deposition

  • 摘要: 一般致密SiC材料的制备需要极高的温度,而降低制备温度一直是SiC制备领域的重要研究方向。采用流化床化学气相沉积法,在球形二氧化锆陶瓷颗粒上制备了厚度为几十微米的SiC包覆层。通过对不同温度SiC包覆层的显微形貌及微观结构变化规律研究,给出了沉积效率变化规律,发现低温产物富硅,而高温产物富碳。对不同氩气含量的实验研究发现,氩气的加入可以促进沉积反应向富碳方向移动,从而可以在显著降低温度的条件下制备出致密SiC包覆层。综合实验结果给出了流化床化学气相沉积方法在不同温度及氩气浓度条件下制备SiC的物相分布图。

     

    Abstract: Usually, it requires extremely high temperature for preparation of SiC materials, so it is an important research direction for reducing the preparation temperature of SiC. SiC coating layer with a thickness of many microns on the ZrO2 spherical ceramic particles was synthesized using the fluidized bed chemical vapor deposition method. Through the study of microscopic morphology and microstructure change rule of SiC coating layer deposited at different temperatures, the deposition efficiency variation rule is obtained, and it is found that the low temperature product is silicon-rich, and the high-temperature product is carbon-rich. It is also found that the addition of argon can promote the deposition reaction toward to the carbon-rich direction by experimental study of different argon contents, so dense SiC coating layer can be prepared in the condition that the temperature is significantly reduced. Based on experimental results, the diagram map of SiC phase distribution with the variation of temperature and argon concentration in the fluidized bed chemical vapor deposition system is also given.

     

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