CMAS and High Temperature Resistant LaMgAl11O19 TBC Coatings Using a Microwave Based Uniform-Melt-State Plasma Process (UniMelt)

Amastan, in collaboration with the University of Connecticut, proposes to make high temperature phase stable and CMAS resistant coatings of lanthane hexaaluminate (LaMgAl11O19) material as a suitable substitute to YSZ top coat for thermal barrier coating applications. These coatings, although deposited by atmospheric plasma spray (APS) exhibit comparable coefficient of thermal expansion and thermal conductivity to that of traditional YSZ top coat. These remarkable thermo physical properties were obtained despite the non homogeneity of material composition and non uniform thermal path inherent to APS. Amastan will demonstrate homogeneous LaMGAl11O19 coatings with better control of phase and microstructure through the use of its innovative spray process called Uniform Melt State Process (UniMelt). This process offers uniform melting in three dimensions of the processed materials by axial injection of uniform precursor droplets into an axis-symmetric plasma hot zone with laminar process gas flow and uniform temperature profile. The innovative thermal process will lead to more homogenous coatings with more stable microstructure and precise control of the materials phase due to better control of material composition, particle size and uniform thermal processing path. Caterpillars Solar Turbines and Pratt & Whitney have both expressed interest in supporting and participating in our Phase I study.