Improvement of the Oxidation Resistance of the Single-Crystal Ni-Based TMS-82+ Superalloy by Ni–Al Coatings with/without the Diffusion Barrier

• DOI: 10.1007/s11085-010-9211-9
• Publication Date: 2010-09-01T11:21:55Z
• Authors: Y. Wu; X. W. Li; G. M. Song; Y. M. Wang; T. Narita
• Keywords: Diffusion barrier; Non-blocking I/O; Barrier layer

Oxidation behavior of the uncoated base, Ni–Al coated and Re–Cr-Ni plus single-crystal (SC) Ni-based TMS-82+ superalloy is studied under cyclic air at 900 °C for 200 h to assess oxidation resistance. Regardless coating processing, effective in improving resistance due formation a continuous α-Al2O3 layer scale. For base superalloy, mass-gain curves are fitted by subparabolic relationship, complex oxide products including predominately NiO, some CrTaO4, α-Al2O3, Cr2O3, minor spinels (Ni, Co)Al2O4, AlTaO4 θ-Al2O3 detected. Time-dependence growth rate both with/without diffusion barrier explained parabolic relationship. The scales consist θ-Al2O3. σ-phase plays negligible effect on during exposure environment. amount detrimental γ′-phase topologically close-packed (TCP) phases interdiffusion zone with greatly reduced compared that without distinct limiting elements between bond-coat substrate.