Thermal stability and mechanical properties of cold-sprayed Nickel-Yttria coating

• Published in: Scripta materialia Vol. 207; no. C; p. 114281
• Main Authors: Gwalani, Bharat, Song, Miao, Silverstein, Joshua, Escobar, Julian, Wang, Tianhao, Pole, Mayur, Johnson, Kyle, Jasthi, Bharat K, Devaraj, Arun, Ross, Kenneth
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 15.01.2022; Elsevier
• Subjects: Atom probe tomography; Cermet coating; Cold spray; Nano Yttria; Transmission electron microscopy; Nano Yttria; Transmission electron microscopy; Cermet coating; Cold spray; Atom probe tomography
• ISSN: 1359-6462; 1872-8456
• DOI: 10.1016/j.scriptamat.2021.114281

The microstructural evolution under the extreme environments imposed during cold spray deposition and the microstructural recovery during post-processing annealing treatments is rather complex and not well understood. Here, Nickel-Yttria (Ni-Y2O3) cermet coatings on a 304 stainless steel (SS304) substrate were produced using cold spray technique, resulting in a bimodal grain structure. The phase stability, mechanical properties are investigated in both as-deposited and annealed (350 ⁰C) Ni-Y2O3 coatings. A multimodal microstructural characterization using electron microscopy, and atom probe tomography shows the structural and compositional stability of Y2O3 particles and Ni grains. A fragmentation of Y-rich particles and dispersion in Ni was observed, however, no forced mixing/dissolution of Y in Ni is detected. As compared with pure Ni coating (control test), Ni-Y2O3 coating slowed a retarded grain growth during annealing. Additionally, Ni-Y2O3 coating was 1.5 times harder and showed better thermal and mechanical stability compared to the Ni coating after annealing. [Display omitted]