Enhancing hot oxidation resistance of the HVOF-sprayed NiCoCrAlTaY coating by alumina nanoparticles via a modified suspension route

• Published in: Journal of materials research and technology 2023-01, Vol.22, p.3387-3401
• Main Authors: Hosseini, Yasamin, Kermanpur, Ahmad, Ashrafizadeh, Fakhreddin, Keyvani, Ahmad
• Format: Article
• Language: English
• Subjects: Al2O3 nanoparticles; High velocity oxygen fuel (HVOF); Hot oxidation; NiCoCrAlTaY coating
• ISSN: 2238-7854
• DOI: 10.1016/j.jmrt.2022.12.185

The effect of alumina (Al2O3) nanoparticles on the hot oxidation behavior of NiCoCrAlTaY coating is investigated. High velocity oxygen fuel (HVOF) technique was employed to deposit coatings on a single crystal CMSX-4 Ni-based superalloy. Different amounts of α-Al2O3 nanoparticles (3, 6 and 9 wt%) were added to NiCoCrAlTaY powder via a modified suspension route. By this modification, the Al2O3 nanoparticles were adhered on the surface of the atomized metallic NiCoCrAlTaY powders with a relatively uniform distribution. The composite powder was then sprayed on the superalloy substrate by an industrial HVOF route. The cyclic hot oxidation resistance of the coatings was evaluated at 1100 °C. Results showed that the coating with 6 wt% nano-Al2O3 experienced significantly better oxidation performance. The presence of nano-Al2O3 in the coating accelerated the formation of α-Al2O3 dense oxide layer and, thereby, delayed diffusion of other elements to the surface. Adding more Al₂O₃ nanoparticles up to 9 wt% led to an increase in porosity and surface roughness of the coating which decreased oxidation resistance.