Kunhong Hu

Synergistic lubrication of MoS2 particles with different morphologies in liquid paraffin

Purpose – The purpose of this paper is to explore the synergistic lubrication of MoS2 particles with different morphologies.Design/methodology/approach – The synergistic lubrication of MoS2 particles with different morphologies is evaluated using a four‐fall tribometer in liquid paraffin.Findings – Results show that the morphology of MoS2 has an influence on the tribological properties of MoS2. Both MoS2 nano‐balls and nano‐platelets function as lubrication additives in liquid paraffin better than MoS2 micro‐platelets do. It is also found that there is a synergistic lubrication between two different morphologies of MoS2. The composite MoS2 additives with different morphologies can improve the wear resistance and friction reduction of liquid paraffin more than each of them singly does. The synergistic lubrication between two different MoS2 morphologies results from the cooperation of their different lubrication mechanism.Originality/value – The paper reveals a synergistic lubrication between two different ...

Synthesis and tribological properties of MoS2 composite nanoparticles with different morphologies

Abstract Molybdenum disulphide composite particles made of both hollow nanospheres and nanoplatelets were synthesised in a single process using a chemical method that was optimised by adjusting the relative proportions of Na2S and thioacetamide (TAA) precursors. The composite nanoparticles were characterised using powder X-ray diffraction, transmission electron microscopy and thermal analysis; four-ball tribological tests were used to assess their lubricating effect when used as additives in liquid paraffin dispersions. The results showed that composite nanoparticles of appropriate shape distribution could only be synthesised with a high dosage of TAA: too high concentrations of Na2S were shown to destroy the template chain of TAA and disturbed the formation of nanospheres. The MoS2 composite particles exhibited a better lubricating effect as compared to composite particles produced by mechanical mixing of separately produced nanospheres and nanoplatelets, confirming that the chemical method can lead to a better synergistic lubrication between two kinds of MoS2 nanoparticles.

Tribology of MoS2-Based Nanocomposites

In this chapter, the preparation and tribological properties of MoS2-based nanocomposites were reviewed, including nanocomposites of MoS2 with different morphologies, MoS2/inorganic compound nanocomposites, MoS2/polymer nanocomposites, and Ni–P–(nano-MoS2) composite coatings. The nanocomposites of MoS2 can be prepared by mechanical-mixing two kinds of nano-MoS2 with different morphologies or chemically synthesizing from sodium molybdate and different sulfides. The nanocomposites of MoS2 reveal better tribological properties than their original materials. Moreover, the chemical method presents advantages over the mechanical one in the preparation of the MoS2 nanocomposites with different morphologies for lubrication applications. Using an appropriate chemical method may produce MoS2/inorganic compound nanocomposites such as MoS2/TiO2 nanocomposite. Two kinds of nanoparticles (nano-MoS2 and nano-TiO2) reveal a synergistic effect on the tribological properties of the MoS2/TiO2 nanocomposite. MoS2/polymer nanocomposites may be prepared by adding nanosized MoS2 into polymers or using the chemical intercalation technology. The chemical intercalation technology may lead to disperse MoS2 into polymer matrix better than the mechanical-filled way. However, the intercalation compound of MoS2/polymer can not present a satisfactory lubrication performance, because the intercalation process destroys the 2H structure of MoS2 with better lubricity. The Ni–P coatings may be co-deposited with nanosized MoS2 on medium carbon steel substrate by electroless plating. The obtained Ni–P–nano-MoS2 composite coating shows an excellent lubricating performance. The present review concluded the synthesis and tribological applications of MoS2-based nanocomposite well.