Estimation of thermophysical properties of thermal barrier coatings for gas turbine hot parts

摘要

In order to evaluate thermal barrier performance of TBCs quantitatively, which used for gas turbine combustor, bucket and nozzle, six types of TBC made of plasma spray powder were tested. Average powder size, powder configuration, and chemical components were taken as the parameters of plasma spray powder to measure the thermophysical properties and to analyze microstructure on the as-sprayed TBCs and heat-treated TBCs. The results of thermophysical property measurements indicated that thermal conductivity of heat-treated TBCs was two to three times larger than that of the as-sprayed TBCs. The results of microstructure analyses revealed that the increase of thermal conductivity of TBCs is caused by changes occurring in the crystalline structure and reduction of un-contact area in TBCs. From the results, the changes in thermal conductivity of TBCs were expressed as coefficients of porosity in the early stages, crystalline structure, and heating time and temperature.