Synergistic lubrication of few-layer Ti_(3)C_(2)T_(x)/MoS_(2) heterojunction as a lubricant additive

The few-layer Ti_(3)C_(2)T_(x)/MoS_(2) heterostructure was successfully prepared via vertically growing of MoS_(2) nanosheets on the few-layer Ti3C2Tx matrix using hydrothermal method.The tribological properties as additive in mineral oil(150N)were evaluated in detail.The 0.3 wt% of few-layer Ti_(3)C_(2)T_(x)/MoS_(2) heterostructure addition amount can reduce the friction and wear of 150N by 39% and 85%,respectively.Moreover,the enhancement effect of few-layer Ti_(3)C_(2)T_(x)/MoS_(2) on tribological properties of 150N is superior to that of few-layer Ti_(3)C_(2)T_(x),MoS_(2) nanosheets,and their mechanical mixture.Based on the characterization and analysis of wear debris and wear track,such excellent tribological properties of the few-layer Ti_(3)C_(2)T_(x)/MoS_(2) heterostructure derive from its structural advantage toward good dispersion,the synergistic lubrication of Ti_(3)C_(2)T_(x) and MoS_(2) nanosheets during the rubbing process,and the formation of tribo-film.

Optimization of several surface treatment processes for alleviating fretting damage of a locking pin

The operational safety and reliability of a variable gauge train are affected by the anti-fretting wear performance of the locking mechanism.The main purpose of this study is to optimize the surface treatment process for a locking pin material under actual service conditions to alleviate fretting damage.Based on the two basic principles of surface strengthening and friction reduction,a substrate(AISI 4135 steel)surface was treated by laser quenching(LQ),plasma nitriding(PN),and bonded MoS2 coating.Systematic fretting wear tests were conducted,and the wear behavior and damage mechanism of various treated surfaces were comprehensively investigated.The results indicate that the wear resistances of the LQ-and PN-treated surfaces were significantly improved,and their main wear mechanisms were abrasive wear,delamination,and oxidation wear.The MoS_(2) coating exhibits the lowest friction coefficient and energy dissipation due to its self-lubricating property,but it incurs the highest wear rate and failure in the form of plastic deformation.Furthermore,the rough compound layer with a high hardness on the PN-treated surface is conducive to the formation and maintenance of the third-body contact at the fretting interface,consequently resulting in a significant reduction in wear.An optimal surface treatment process for alleviating fretting damage of the locking pin is recommended via comprehensive evaluation,which provides a reference for the anti-fretting protection of related mechanical components.