Structural Optimization for Porous Thermal Barrier Coating and Analysis of Thermomechanical Properties by Experimental and Computational Investigation

Abstract

The porous thermal barrier coatings (TBCs) play a pivotal role in aircraft industry by improving the energy efficiency of TBCs system. Specifically, the pore structure features are significant factors for the performance of porous TBCs. However, atmospheric plasma spraying (APS), as a commonly used TBCs deposition technology, is difficult to control the geometric characteristics and distribution of pores. In this situation, an attempt has been carried out in this study to produce porous TBCs with controlled pore characteristics by delivering pore former using the plasma co-spraying technique. The influence of deposition parameters on pore geometry and distribution was analyzed in this process. To clarify the influence of pore structure features on thermomechanical properties of the coatings, experimental and finite element simulations were developed. The results suggested that pore content, perimeter, aspect ratio (A/R), and distribution can be effectively regulated by the method developed in this study. The coatings with lower elastic modulus and thermal conductivity were obtained with increased porous embedded particle clusters (PEPC) area fraction. The transverse distributed flattened shuttle-shaped PEPC in the coating has a larger perimeter and A/R value, resulting in superior potential in reducing the thermal conductivity and producing a greater elastic modulus.

Keywords: Porous thermal barrier coating, Atmospheric plasma spray, Structural optimization, Finite element analysis, Thermomechanical properties