High temperature oxidation of HFPD thermal-sprayed MCrAlY coatings in simulated gas turbine environments

Author: Belzunce F.   Higuera V.   Poveda S.   Carriles A.  

Publisher: Springer Publishing Company

ISSN: 1059-9630

Source: Journal of Thermal Spray Technology, Vol.11, Iss.4, 2002-12, pp. : 461-467

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Abstract

NiCrAlY and CoNiCrAlY powders were thermal-sprayed using the high frequency pulse detonation method (HFPD) onto AISI 310 austenitic stainless steel samples to obtain dense, adherent, high temperature oxidation resistant coatings. The oxidation behavior of both types of coatings in a 1000°C simulated gas turbine environment was experimentally determined. The porosity, hardness, coating thickness, and microstructure were not significantly modified by the high temperature oxidation cycles, but the internal oxidation increases significantly after a very low oxidation time. Surface phase composition was evaluated using x-ray diffraction (XRD) and scanning electron microscope (SEM) techniques, revealing the formation of a continuous and highly protective alumina layer. The oxidation kinetics of both coatings can be characterized by parabolic rate constants, which are very close to those for the formation of aluminum oxide on nickel or cobalt based alloys at similar conditions.