Advanced thermal barrier coating systems

Current stateoftheart thermal barrier coating (TBC) systems consist of partially stabilized zirconia coatings plasma sprayed over a MCrAlY bond coat. Although these systems have excellent thermal shock properties, they have shown themselves to be deficient for a number of severe diesel and aircraft applications. New ternary ceramic plasma coatings are discussed with respect to their possible use in TBC systems. Ceriayttria stabilized zirconia (CYZ) coatings have been developed with low thermal conductivities, excellent thermal shock resistance, and erosion resistance comparable to baseline yttria stabilized zirconia (YSZ) coatings. In addition, dense zirconiatitaniayttria (ZTY) and chromiatitaniasilica (CTS) coatings have shown particle erosion resistance properties exceeding conventional stabilized zirconia coatings. Coatings have been evaluated in conjunction with a NiCrAlCoY2O3 bond coat. Also, multilayerhybrid coatings consisting of a bond coat with subsequent coatings of ceriayttria stabilized zirconia (CYZ) or yttria stabilized zirconia (YSZ) and top coats of zirconiatitaniayttria (ZTY) or chromia titania silica (CTS) have been evaluated. These coating systems combine the enhanced thermal shock performance characteristics of CYZ or YSZ with the improved erosion resistance of ZTY or CTS coatings.