A numerical model of a supersonic compressible plasma flow has been developed with the aid of CFD software to describe the thermodynamic and transport properties of a plasma jet in order to investigate the PS-PVD process and how to optimize it for thermal barrier coatings and, in particular, the formation of columnar microstructures. The required properties of the plasma gas mixtures were obtained as a function of temperature and pressure from thermodynamic calculations in chemical equilibrium with the effect of ionization. Two-dimensional Monte Carlo simulations were conducted to provide insight on the evolution of columnar microstructure, accounting for self-shadowing and vapor incidence angle but ignoring the effect of diffusion. Simulated structures and predicted values are presented and compared with actual images and measurements.

Oxyfuel combustion efforts to burn fossil fuels with oxygen, for easier post-combustion CO 2 capture, include schemes to use flue gas to drive turbines for power generation. The environment examined here is 10% CO 2 and 0.2% O 2 , with the balance being steam, with temperatures ranging from 630 to 821 °C. The relatively high C and O 2 activities of this environment, as compared to pure steam, may lead to changes in oxidation behavior and mechanical properties. Oxidation coupons of Ni- and Co-base superalloys, in both bare metal and TBC coated conditions, were exposed to this environment for up to 1000 hours. The results of these exposures, in terms of mass gain and scale morphology, are presented.