Modeling and simulation in the production process control and material property calculation of complex structured EB-PVD TBCs

This article gives an overview about basic research work related to the adaption of the Electron Beam-Physical Vapor Deposition (EB-PVD) process to produce thermal barrier coatings with complex microstructures. Modeling and simulations methods were applied in the process control to produce coating with defined structural parameters and in the minimization procedure of the coating's effective thermal conductivity. The calculation of the thermal conductivity is based on the homogenization by physical equivalence method and FEM modeling was applied. The calculated thermal conductivity values could be validated by experimental measurements of coated specimens with defined microstructures. These defined microstructures could be deposited by using the developed process control algorithm. Two strategies were investigated during research work, one is based on the modeling of ideal microstructures with a perfect sinusoidal or zigzag shape. The process control algorithm had to be adapted to meet these ideal structures. The other strategy is based on real deposited structures which form an input for the FEM models. The modeling procedure had to be adapted to the real microstructures in this case. Other phenomena were also part of research work like heat transfer phenomena at the coating surface (radiation, convection) and there influence on the thermal conductivity. (C) 2006 Elsevier B.V. All rights reserved.