Considerable research efforts have been explored attempting to enhance the thermal durability of thermal barrier coatings (TBCs) at the high operating temperatures of gas turbines. In this study, the suspension plasma spray (SPS) process was applied to produce TBCs with a segmented structure by using an yttria-stabilized zirconia (YSZ) suspension. Four different experiment sets were carried out by controlling the ratio between surface roughness of the bond coat and feed stock size (Ra/D50) in order to examine the effect of Ra/D50 ratio on the microstructure of SPS-prepared coatings. When the Ra/D50 had a high value of 11.8, a deposited thick coating turned out to have a cone-type columnar microstructure. In contrast, at the low Ra/D50 values of 2.9 and 0.18, a deposited thick coating appeared to have a dense, vertically-cracked microstructure. However, with the very low Ra/D50 value of 0.05 the coating was delaminated.
ASJC Scopus subject areas
- Ceramics and Composites