Evolution of pore microstructure in thermal barrier coatings studied by SANS

摘要

Two different sample morphologies, resulting from different EB-PVD process parameters, were investigated by SANS in the as-coated condition and after heat treatment at 1100 degrees C for 1, 10 and 100h. SANS measurements perpendicular to the surface show highly anisotropic 2-D pattern which vary for the different morphologies. Quantitative information of the surface area were determined by converting the 2-D data to 1-D scattering patterns averaged over sectors of 5 degrees and calculating the apparent Porod constant as a function of the angle. The apparent Porod constants show a preferred orientation of the pores in the as-coated conditions and a decreasing surface area for the heat treated samples. The corrected anisotropic 2-D data were fitted with a 3-D structure model to receive the interface orientation distribution of the pores. The shape of the pores changes with increasing temperature and time. (c) 2006 Elsevier B.V. All rights reserved.