Gearing Up Solution Precursor Plasma Spray for YAG TBCs for Production

Abstract Yttrium aluminum garnet (YAG) has desirable properties for a thermal barrier coating (TBC), although there are two production challenges. One, YAG has a relatively low thermal expansion coefficient which leads to large thermal mismatch stresses, and two, amorphous phases are produced by atmospheric plasma spraying. Solution precursor plasma spraying (SPPS) has to potential to solve both problems. First off, it produces no amorphous phases. Secondly, it can produce a cracked microstructure that mitigates the CTE mismatch issue. To judge the adequacy of the properties of SPPS YAG, a summary of the properties of common TBCs is presented. It is shown that the properties of SPPS YAG fall within desirable or usable ranges. Current efforts described in this paper focus on improving the efficiency and rate of deposition.