Zirconate-Aluminate CMAS Resistance Demonstrated in Latest Publication

In a recent article titled "Enhanced calcium–magnesium–aluminosilicate (CMAS) resistance of GdAlO3 (GAP) for composite thermal barrier coatings" published in the Journal of the American Ceramic Society, authors at HAMR Industries LLC and Penn State University’s Applied Research Laboratory demonstrated the unique benefits afforded to aluminate-zirconate thermal barrier coating (TBC) compositions when experiencing calcium-magnesium-alumino-silicate (CMAS) degradation. Dense GdAlO₃ (GAP) and Gd₂Zr₂O₇ (GZO) pellets were evaluated for their CMAS infiltration resistance and overall reaction behavior, while CMAS-TBC mixture pellets were used to assess the equilbrium behavior of the two materials. The team demonstrated that the apatite reaction promoted by GZO was present in GAP and potentially more effective in blocking CMAS infiltration.

This research is another critical step in the development and advancement of composite TBCs as a replacement of todays most advanced zirconate materials. Previous work by the team demonstrated the effectiveness of GAP in toughening GZO materials and coatings, but the CMAS behavior was unknown. Demonstrating that GAP not only performs well under select CMAS conditions, but potentially out performs today's most CMAS resistance composition, is encouraging for its use in composite and layered solutions. With a provisional patent submitted by Penn State and authored by Dr. Schmitt of HAMR Industries and Dr. Wolfe of Penn State, the research further demonstrates the efficacy of this material system and the enormous potential it may have for next-generation gas turbines.