Tribological Properties of SiO2@Cu and SiO2@MoS2 Core–Shell Microspheres as Lubricant Additives

Xiaoliang Ma,Yuting Li,Xiaoqiang Fan,Peng Feng,Chaoliang Gan,Minhao Zhu,Xiangyuan Ye,Xiaopeng Li

doi:10.1007/s11249-021-01483-1

Xiaoliang Ma, Yuting Li + Show 6 more

Open Access

https://doi.org/10.1007/s11249-021-01483-1

Copy DOI

Abstract

Herein, core–shell structural SiO2@Cu and SiO2@MoS2 microspheres were prepared using SiO2 as hard core, Cu and MoS2 as shell. As lubricant additives were introduced into base oil (PAO 40), their friction reduction and wear resistance were investigated in detail. Comparing with onefold additive (SiO2, Cu and MoS2), such core–shell structural additives can improve the tribological behaviors at the Hertz contact stress range of 1.26–2.72 GPa (SiO2@Cu reduces the friction and wear up to 32.47% and 67.86% at 2.72 GPa, respectively). Besides, the tribological properties of SiO2@Cu microspheres are superior to that of SiO2@MoS2 (the wear volume was reduced by 48.45% at 2.72 GPa). The excellent tribological behaviors of SiO2@Cu microspheres can be ascribed to its structural advantage, the synergistic effect of hard SiO2 core and Cu shell. The rolling effect of SiO2, easy-shearing and self-repairing of Cu shell offer a synergistic lubrication function and form a dense protection film, thereby contributing to the optimal lubrication performance.

Highlights

Energy losses across all mechanical systems are primarily attributed to friction and wear of moving elements
With the development of nanotechnology, a considerable number of solid particles with different structures have been fabricated to regulate the tribological behaviors of lubricating oil [2, 8]
The results show that the average diameter of SiO2@MoS2 microspheres was about 683 nm, and the thickness of MoS2-nanolayer was about 30 nm

Summary

Introduction

Energy losses across all mechanical systems are primarily attributed to friction and wear of moving elements. An important research topic in the field of tribology is to explore high performance solid lubricant additives with low friction and high wear resistance, in view of their small size and thermal stability [5,6,7]. Hard solid particles such as SiO2 and ZnO will scratch the contact surface causing abrasive wear, and soft particles such as Cu and PMMA cannot be suitable for harsh conditions due to their poor mechanical strength. The traditional mechanical mixing method is easy to produce problems such as phase separation or uneven dispersion, which cannot achieve the technical requirements of low friction and wear resistance under harsh working conditions [9,10,11]

Objectives

Results

Conclusion