Journal of Inorganic Materials

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Effects of Deposition Temperature on the Microstructures of SiC Coatings by CVD

ZHANG Chang-Rui, LIU Rong-Jun, CAO Ying-Bin   

  1. Key Laboratory of National Defense Technology, College of Aerospace & Materials Engineering, National University of Defense Technology, Changsha 410073, China
  • Received:2006-02-20 Revised:2006-05-25 Published:2007-01-20 Online:2007-01-20

Abstract: The coatings of SiC were prepared from the methyltrichlorosilane (MTS) by low pressure chemical vapor deposition from 950℃ to 1300℃. SEM was used to characterize the surface and cross-sectional morphologies of the as deposited coatings. The effects of temperature on the microstructures of SiC coatings were investigated. At 950℃, the as-deposited SiC coating is loose and the grains of the coating are fine. In the temperature range of 1000-1100℃, CVD SiC coatings show a dense and smooth surface morphology. However, in the temperature range of 1150-1300℃, the surface morphology of SiC coatings changes to rounded hillocks and the as-deposited coatings are very rough. Factors influencing the surface morphologies and structures of SiC coatings were studied through thermodynamics and nucleation-growth theory. The relationship between deposition temperature and SiC coatings’ cross-sectional morphologies can by listed as follows, the as deposited coatings are very dense and there are no holes when the deposition temperature is lower than 1200℃, however, the as deposited coatings become very loose at 1300℃. The inside structures of SiC coatings were interpreted by the island growth
model.

Key words: chemical vapor deposition, SiC, temperature, coatings, microstructure

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