Interaction between Vapor Species and Graphite Crucible during the Growth of SiC by PVT

Graphite crucible in seeded sublimation growth of Silicon Carbide (SiC) single crystal does not only act as a container but also as an additional carbon source. The modeling of the growth process integrated with the etching phenomenon caused by the interaction between vapor species and the graphite crucible is shown to be able to predict the shape of the crystal front during the growth. The additional fluxes produced at the graphite part are delivered to the growing crystal mainly at the crystal periphery. The results obtained from the modeling are in good agreement with the experimental ones.

Thermal Analysis of Halide Activator Used in Aluminizing of TiAl Intermetallics

A detailed study of thermal analysis of ZrCl4 was carried out to investigate the influence of the halide salt type activator on the growth behavior of coating formed in vapor phase aluminizing process and subsequently to identify the most suitable condition. The equilibrium partial pressures of vapor species generated at the decomposition temperature of ZrCl4 were calculated by using a procedure based on minimization of the whole Gibbs energy with Factsage 6.2 using Fact 53 and SGsold thermodynamic databases. The results were discussed and compared with literatures. With the aid of thermodynamic analytical tools, chloride salt activator was analysed and the decomposition temperature with related enthalpy change was evaluated.