Experimental and numerical study of thermal conductivity of plasma-sprayed thermal barrier coatings with random distributions of pores

Numerical and experimental investigations were conducted to find the effect of percentage and distribution of porosity and heat treatment on the conductivity value in the plasma-sprayed thermal barrier coatings (TBC). The numerical analysis of the SEM images of six plasma-sprayed samples showed an explicit relation between changes in the porosity percentage and the conductivity. Also, with a similar analysis, it was shown that the distribution of porosity and its orientation do not have a significant impact on the conductivity magnitude. A correlation was established for the variation of conductivity with respect to the material porosity. The experimental results indicated that applying a heat treatment at 1070 °C leads to an increase in the conductivity for 5-30% in the APS TBCs.