Patent ID: 10865476

Abstract:
CVD Alumina coating has been one of the most important materials for wear resistant application for many years. Recently, texture control in α-Al2O3 has attracted increasing attention due to the possibility to further improve the anisotropic properties such as thermal conductivity and mechanical properties. The influence of process parameters on textures is complex. In the present application, the influence of nucleation surface condition and H2S on the texture in CVD α-Al2O3 coatings has been investigated. It has been shown that without the addition of H2S, the crystal orientation in the Al2O3 coatings is primarily dominated by the nucleation surface condition, whereas the effect of reactant composition on texture is minimal. On the other hand, in the presence of H2S during growth, reactant composition also plays an important role in affecting the crystal orientation. This effect is likely due to the strong interaction between the Al2O3 surface and the H2S.