| Aluminum oxide was deposited with a CVD-technique onto TiC-coated cemented carbide substrate. The effects of reaction parameters; deposition temperature, total pressure, CO₂/H₂mole ratio, AlCl₃, partial pressure, on the CVD of Al₂O₃were investigated. The experimental results showed that deposition rate was increased with an increase in deposition temperature and total pressure, and maximum deposition rate was obtained when CO₂/H₂mole ratio is unity. It was also found that up to the critical value of AlCl₃partial pressure, deposition rate was increased with an increase in AlCl₃partial pressure, but above the critical value deposition rate was decreased with an increase in AlCl₃partial pressure. The structure of Al₂O₃was changed from amorphous one to crystalline with an increase in deposition temperature. The reaction of Al₂O₃formation was controlled by chemical kinetics at lower temperature (< 1000℃), but the control mechanism of the reaction changed to mass transport at higher temperature (> 1000℃). |
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