Microstructural investigation of the breakdown of the protective oxide scale on a 304 steel in the presence of oxygen and water vapour at 600 °C M. Halvarsson a, * , J.E. Tang a , H. Asteman b , J.-E. Svensson c , L.-G. Johansson b a Department of Applied Physics, Chalmers University of Technology, SE-412 96 Go ¨teborg, Sweden b Department of Chemistry, Go ¨teborg University, SE-412 96 Go ¨teborg, Sweden c Department of Environmental Inorganic Chemistry, Chalmers University of Technology, SE-412 96 Go ¨teborg, Sweden Received 1 September 2004; accepted 9 August 2005 Abstract This article focuses on the detailed microstructural investigation of the oxide scale formed on a 304 steel in the presence of oxygen and water vapour (40%) at 600 °C. The work has been carried out using a combination of microanalytical techniques including FIB, TEM, EDX and electron dif- fraction. The local breakdown of the initially protective oxide scale and the growth of island/crater oxide morphology are described. Special consideration is given to the influence of the microstructure of the steel and the oxide scale on the breakdown behaviour. Ó 2005 Published by Elsevier Ltd. Keywords: Stainless steel; Oxidation; FIB; TEM; Vaporization 1. Introduction In oxidizing environments at moderately high temperatures, austenitic stainless steels tend to form a Cr-rich oxide that protects the material against further oxidation [1,2]. This 0010-938X/$ - see front matter Ó 2005 Published by Elsevier Ltd. doi:10.1016/j.corsci.2005.08.012 * Corresponding author. Tel.: +46 31 772 3398; fax: +46 31 772 3224. E-mail address: mats.halvarsson@fy.chalmers.se (M. Halvarsson). Corrosion Science xxx (2005) xxx–xxx www.elsevier.com/locate/corsci ARTICLE IN PRESS