Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Mechanical and Civil Engineering

First Advisor

Pei-feng Hsu

Second Advisor

Ju Zhang

Third Advisor

Hamidreza Najafi

Fourth Advisor

Hector M. Gutierrez


Thermal barrier coatings (TBCs) based on the yttria-stabilized zirconium dioxide (YSZ) are widely used in gas turbines. With increasing gas turbine combustion temperature to improve the thermal efficiency, the radiative heat transfer properties of YSZ coatings become important. Currently there is no clear understanding the relationship between the coating microstructure and the radiative properties. In this study, a hybrid computational approach is developed to invert the radiative properties form the spectral measurement. To investigate the relationship between the radiative properties and microstructure, a predictive model of the scattering coefficient is developed based on the pore size distribution obtained from SEM images. To modify the microstructure to enhance the scattering coefficient and the resulting higher thermal resistance of YSZ coatings, a new approach of mixing the polyester powders with the YSZ powders is developed. In this approach the polyester particle size and the mixing ratio are two factors that can alter coating microstructure. The resulting scattering coefficient is significantly larger than that of the YSZ films fabricated in the regular thermal spray process.


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Available for download on Thursday, July 31, 2025