Growth and structure of TiC coatings chemically vapour deposited on graphite substrates |
| |
Authors: | S Eroglu B Gallois |
| |
Affiliation: | (1) Department of Materials Science and Engineering, Stevens Institute of Technology, 07030 Hoboken, NJ, USA;(2) Present address: Marmara Research Center, Materials Research Division, TUBITAK, Gebze-Kocaeli, Turkey |
| |
Abstract: | TiC coatings were grown on graphite substrates by the chemical vapour deposition technique, using gas mixtures of CH4-TiCl4-H2 at a total pressure of 10.7 kPa and at temperatures of 1400 and 1425 K. The growth rate and structure of the TiC coatings were investigated as a function of CH4 and H2 concentrations. The deposition rate of TiC increased with increasing CH4 flow rate, but did not change with H2 flow rate. This behaviour was explained by a mass transport theory. Thermodynamic analyses based on minimization of Gibbs' free energy predicted carbon codeposition with TiC. X-ray diffraction and Auger electron spectroscopy (AES) studies and microstructural observations, however, suggested that free carbon did not form. Textural analyses indicated that the growth of TiC coatings was initiated as randomly oriented crystallites, and as the thickness of the coatings increased, preferentially oriented columnar grains developed. The textures of TiC coatings with the same thickness changed from the 110 orientation to the 100 orientation with decreasing H2 flow rate for a constant CH4 flow rate. The CH4 concentration also greatly influenced the preferred orientation of the coatings. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|