Production and characterization of ceria and yttria stabilized zirconia thermal barrier coatings on IN 738 superalloy

Thermal barrier coatings (TBCs) in gas turbine engines are extensively used to produce thermal insulation for hot sections and to increase the turbine efficiency. The purpose of this investigation is the production and characterization of a two layer thermal barrier coating consisting of ceria and yttria stabilized zirconia (CYSZ) top coat and NiCoCrAlY bond coat on the superalloy substrate. For this scope، NiCoCrAlY bond coat followed by CYSZ coating were deposited on the substrates of IN 738 coupons by atmospheric plasma spraying (APS). Adhesion strength test was done similar to ASTM C633-01. To evaluate thermal insulation capability، the thermal insulation capacity test was performed. For coating characterization، microstructural investigation using field emission scanning electron microscope (FESEM) and phasic analysis using x-ray diffractometer (XRD) were performed. Results revealed that using atmospheric plasma spray process can fabricate the Thermal barrier coating with high thermal insulation capability.