Tribological performance analysis of nano-FeS films deposited on the surface of bearing steel

The wear and adhesion of bearing surface under boundary lubrication is the key to the development and application of bearing technology. For improving the antifriction and antiadhesion properties of the bearing materials, the sulfur rich nano self-lubricating thin layers were prepared on the bearing surface by low-temperature sulfide permeation technology. The morphology and composition of the sulfurized layer were characterized microscopically, and the tribological properties of the sulfurized layer were analyzed to reveal the anti-friction and anti-adhesion mechanism of the sulfurized layer on the surface of bearing steel. The results show that the sulfurized layer is flatter and does not contain nanostructures when the formulation does not contain thiourea, and the content of element S is lower. After the addition of thiourea, the surface of the sulfurized layer is formed by the accumulation of nanosheet-like structures. The nano sulfurized layer has higher S-element content and better tribological properties. When thiourea and tartaric acid are added to the sulfurizing formula at the same time, the nano-sheet structure of the sulfurized layer is more dense and uniform. Moreover, the number of microcracks in the sulfurized layer is small, and the tribological properties are further improved. At the same time, the sulfide in the self-lubricating thin layer and the lubricating oil stored in the gaps can make the bearing surface have a typical "liquid-solid synergistic lubrication effect". That is conducive to the formation of the self-lubricating film and the transfer to the dual parts. All these factors improve the antifriction and antiadhesion properties of the bearing materials effectively. [Display omitted]