9 / 2021-06-10 16:49:42

Role of ceramic nanoparticles on tribological properties of atmospheric plasma sprayed Ni60-based coatings

atmospheric plasma spraying, ceramic nanoparticles, microstructure, tribological properties, boundary lubrication

In order to comparatively investigate the role of ceramic nanoparticles on the microstructure, mechanical properties and tribological properties of Ni60-based coatings, Ni60, 5wt%SiC- Ni6060 and 5wt%SiO₂-Ni60 coatings were deposited onto 304 stainless steel substrates by atmospheric plasma spraying. The micro-hardness, phase compositions and microstructure of the as-sprayed coatings were characterized by micro-hardness tester, X-ray diffractometer and scanning electron microscope, respectively. The friction coefficient and volume wear rate of the as-sprayed coatings were measured. Results illustrated that ceramic nanoparticles could function as reinforcing phases, inducing friction-reducing and anti-wear. And tribological properties of Ni60-based composite coatings under dry and water-lubricated conditions were superior to those of Ni60 coating. The analysis of worn surface revealed that ceramic nanoparticles could fill the pits on the worn surface of the coating. Especially in water lubricated conditions, according to FIB-TEM analyses and XPS results, SiC nanoparticles released onto the friction interface can undergo hydrolysis reaction under water-lubricated condition, and the film containing SiO₂ is formed by the hydrolysis reaction of SiC nanoparticles.