Product Code: ICA13_2009

Microstructure of Mcraly Coatings on Steel Substrates
Authors:
Armando Yanez, Universidade da Coruna; Ferrol Spain
Jose M. Amado, Universidade Da CoruñA; Ferrol Spain
Vicente Amigo, Universidad PolitéCnica De Valencia; Valencia Spain
MaríA J. Tobar, Universidade Da CoruñA; Ferrol Spain
Javier N. Montero, Universidade Da CoruñA; Ferrol Spain
Presented at ICALEO 2013

MCrAlY alloys (where M stands for Ni,Co or both) are commonly used as overlay protective coatings in gas turbine engine components against high temperature oxidation and corrosion. The protective effect of these alloys is due to the formation of a continuous thermally stable oxide layer on the coating surface. These coatings are usually applied by means of plasma spray techniques or physical vapor deposition. In both cases, low porosity and good adherence may be obtained. As an alternative laser cladding can be applied resulting in fully dense layers metallurgically bonded to the substrate.

In this work several types of MCrAlY alloys, differing in their elemental composition, have been deposited on austenitic stainless steel samples by means of laser cladding. The microstructure of the coatings have been characterized by SEM and DRX inspection. As expected, gamma Ni/gamma' Ni3Al or gamma Ni/beta-NiAl phases are observed in hypoeutectic of hypereutectic microstructures depending on the alloy composition. In addition, the high temperature oxidation behaviour of the different deposited alloy types was also analyzed