Per: Jianlin Sun (School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China), Yanan Meng (School of Material Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China), Boming zHANG (SCHOOL OF MATERIAL SCIENCE AND ENGINEERING, UNIVERSITY OF SCIENCE AND TECHNOLOGY BEIJING, BEIJING 100083, CHINA)
Abstract:
MoO3 nanofluid was chosen as an alternative of MoS2 nanofluid for strip cold rolling to prevent the oxidative deterioration of MoS2. Pure MoS2 nanofluid, the mimetic oxidized nanofluids (hybrid nanofluids of MoO3 and MoS2 nanosheets) and pure MoO3 nanofluid were used as rolling lubricants to identify the influence of this oxidative deterioration on lubrication properties of MoS2 nanofluid. Cold rolling experiments were carried out by two-high rolling mills and both rolling forces of each rolling passes and minimum rolling thickness were measured. The tribological properties of different concentrations pure MoO3 nanofluid were tested by a four-ball tribotester. The worn surfaces were analyzed by means of scanning electron microscope (SEM) with energy dispersive spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS). The results show that pure MoO3 nanofluid was confirmed to have similar lubrication properties to pure MoS2 nanofluid. With the application of MoO3 nanofluid, the surface smoothness was almost as fine as the surface lubricated by pure MoS2 nanofluid. An optimal concentration (0.4wt.%) of MoO3 nanofluid that could show best tribological properties was also proposed in this paper. Additively, the main lubrication mechanism of MoO3 nanofluid was obtained. A lubricating film of MoO3, MoO2 and organic reagents was considered to form on the strip surfaces due to the chemisorption and deposition of MoO3 nanosheets. Erosion corrosion was happened during friction process, MoO3 was transformed to MoO2 and iron was oxidized to ferric oxide. Simultaneously, part of organic reagents in the nanofluid was carbonized. The organic reagents can perform extra lubrication in the friction process.
