Frictional shear-induced nanolamellar oxidation and transformation to oxide nanoparticles during pearlitic steel sliding

Abstract

The in situ formation of a tribolayer composed of oxide nanoparticles on the wear surface is an important method for suppressing wear in metals with lamellar structures. However, the complex interaction between microstructure evolution and oxidation in a tribolayer obscures the formation mechanisms of nanolamellar oxidation and transformation. In this paper, samples of tribolayers at different oxidation stages were prepared by a focused ion beam (FIB) lift-out method. The dynamic evolution process and distribution of oxides in tribolayers during the dry sliding process were analyzed by characterization and molecular dynamics simulation. The nanolamellar oxidation processes and the effects of oxide nanoparticles on self-lubricating behavior were investigated. The results showed that oxygen diffused into the nanolamellae, resulting in continuous oxidation and the formation of an oxide/metal interface. The nanolamellar oxides were broken and refined in the further friction process and eventually transformed into oxide nanoparticles. The oxidation process was influenced by frictional shear, and the growth of oxides proceeded along the direction parallel to the nanolamellae with high-density dislocations. The above results provide a theoretical basis for the next step to improve the wear resistance and corrosion inhibition of metals by designing lamellar structures.