In-situ formation of layer-like Ag2MoO4 induced by high-temperature oxidation and its effect on the self-lubricating properties of NiCoCrAlYTa/Ag/Mo coatings. (10th June 2021)

• Record Type: Journal Article
• Authors: Hao, Enkang; An, Yulong; Chen, Jie; Zhao, Xiaoqin; Hou, Guoliang; Chen, Jianmin; Gao, Meizhen; Yan, Fengyuan
• Is Part Of: Journal of materials science & technology. Volume 75(2021)
• Page Start: 164
• Page End: 173
• Publication Date: 2021-06-10
• Subjects: Microstructure evolution -- In-situ formation -- Ag2MoO4 -- Layer-like structure -- High-temperature friction; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2020.10.024
• Languages: English
• ISSNs: 1005-0302

Abstract

Graphical abstract: The environment temperature plays an important role in the microstructure and phases as well as lubricant properties of NiCoCrAlYTa/Ag/Mo coatings. When the temperature is above 600 °C, there are lubricants formed on the surface of NiCoCrAlYTa/Ag/Mo composite coating, such as Ag2 MoO4 and AgCrO2 . Layer-like Ag2 MoO4 could form a continuous lubrication film at 800 °C and let the composite coating present the best tribological properties. Meanwhile, the appreciate hard particles could play a good bearing role during friction, thereby improve the tribological properties of the composite coating. Highlights: NiCoCrAlYTa/Ag/Mo composite coating is designed and prepared. When the temperature is above 600 °C, Ag2 MoO4 and AgCrO2 in-situ form on the coating surface. After sliding at 800 °C, the micro-bulges with layer-like Ag2 MoO4 generate on the coating surface. There are flower-like nano-rods and irregular polyhedral micron-particles formed under 1000 °C. Layer-like Ag2 MoO4 could form a continuous lubrication film at 800 °C. Abstract: Ag-Mo-O ternary oxide has attracted growing attention because of its potential as a solid lubricant at high temperatures. This work designs and prepares NiCoCrAlYTa/Ag/Mo composite coating, performed using high velocity oxy-fuel (HVOF) spraying technology. The environment temperature plays an important role in the microstructure and phases as well as lubricant properties of NiCoCrAlYTa/Ag/Mo coatings. When the environment temperature is above 600 °C, the outer diffusion and oxidation of Ag and Mo lead to the formation of Ag2 MoO4 on the coating surface. Layer-like Ag2 MoO4 could form a continuous lubricant film at 800 °C and consequently let the composite coating present the best tribological properties. Meanwhile, a small number of hard particles could play a good bearing role during friction and improve the tribological properties of the composite coating.