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Journal of Nanomaterials
Volume 2013 (2013), Article ID 251921, 11 pages
http://dx.doi.org/10.1155/2013/251921
Research Article

The Role of Nanostructured Al2O3 Layer in Reduction of Hot Corrosion Products in Normal YSZ Layer

Department of Materials, Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia

Received 26 December 2012; Accepted 10 February 2013

Academic Editor: Sheng-Rui Jian

Copyright © 2013 Mohammadreza Daroonparvar et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

YVO4 crystals and monoclinic ZrO2 are known as hot corrosion products that can considerably reduce the lifetime of thermal barrier coatings during service. The hot corrosion resistance of two types of air plasma sprayed thermal barrier coating systems was investigated: an Inconel 738/NiCrAlY/YSZ (yttria-stabilized zirconia) and an Inconel 738/NiCrAlY/YSZ/nano-Al2O3 as an outer layer. Hot corrosion test was accomplished on the outer surface of coatings in molten salts (45% Na2SO4 + 55% V2O5) at 1000°C for 52 hour. It was found that nanostructured alumina as outer layer of YSZ/nano-Al2O3 coating had significantly reduced the infiltration of molten salts into the YSZ layer and resulted in lower reaction of fused corrosive salts with YSZ, as the hot corrosion products had been substantially decreased in YSZ/nano-Al2O3 coating in comparison with normal YSZ coating after hot corrosion process.