Effect of alloying elements in Ni-base substrate material on interdiffusion processes in MCrAlY-coated systems
Journal article, 2018

he effect of alloying elements in the substrate on the interdiffusion processes between a NiCoCrAlY-coating and model Ni-base superalloys was studied. Four single-crystal substrates Ni-10Cr-8Al-X (wt%, X = 10Co, 9Ta, 6 W) were coated with a conventional NiCoCrAlY-coating and exposed to air for up to 1000 h at 1050 °C. The microstructural analyses (LOM/SEM/EDX) revealed a strong dependence of the coating degradation rate on the substrate composition. The coating applied to the ternary base Ni-10Cr-8Al alloy and to the quaternary Co-containing substrate degraded most rapidly while the Ta addition to the substrate effectively suppressed interdiffusion. The degradation phenomena such as β-NiAl depletion and propagation of the secondary reaction zone (SRZ) were interpreted in terms of a thermodynamical analysis in Thermo-Calc and by using a CALPHAD-based thermodynamic-kinetic diffusion model.

Diffusion modelling

Author

T. Galiullin

Forschungszentrum Jülich

Anton Chyrkin

Forschungszentrum Jülich

Chalmers, Physics, Materials Microstructure

R. Pillai

Forschungszentrum Jülich

R. Vassen

Forschungszentrum Jülich

W. J. Quadakkers

Forschungszentrum Jülich

Surface and Coatings Technology

0257-8972 (ISSN)

Vol. 350 359-368

Subject Categories

Manufacturing, Surface and Joining Technology

Metallurgy and Metallic Materials

Corrosion Engineering

DOI

10.1016/j.surfcoat.2018.07.020

More information

Latest update

12/10/2018