Development of a NiW In Situ Diffusion Barrier on a Fourth Generation Nickel-Base Superalloy
A diffusion barrier based on a NiW electrolytic coating has been developed to limit interdiffusion between a Ni-base superalloy (MCNG) and a β-NiAl bondcoating. Isothermal oxidation tests of 50h at 1100°C confirmed that W-rich layer formed with NiW coating modifies the oxidation behaviour of the bondcoat and limits interdiffusion. The diffusion barrier reduced β-NiAl γ’-Ni3Al transformation in the bondcoating and prevented SRZ formation.
Pierre Steinmetz, Ian G. Wright, Alain Galerie, Daniel Monceau and Stéphane Mathieu
E. Cavaletti et al., "Development of a NiW In Situ Diffusion Barrier on a Fourth Generation Nickel-Base Superalloy", Materials Science Forum, Vols. 595-598, pp. 23-32, 2008