Preparation And Tribological Properties Of Molybdenum Disulfide Nanoparticles

Molybdenum trisulfide (MOS3) nano-particles were firstly obtained by acidifying the mixed solution of M2S and M2MoO4 (M: Na+ or NH/). Then nano-sized molybdenum disulfide (M0S2) particles were produced by the desulphurization of the prepaed M0S3 under H2 atmosphere.In the first-step reaction, an optimized preparation process was investigated after single-factor and orthogonal experiments. Results of characterization by X-ray diffraction (XRD) and transmission electron microscope (TEM) showed that the average size of amorphous M0S3 particles is about 100 nm prepared under the optimized process conditions.Thermodynamic analyses demonstrated the feasibility of the second-step reaction, and studied the possibility of two subsidiary reactions as well. A proper temperature range for the preparation of M0S2 was work out by thermodynamic and kinetic analyses. A kinetic equation was work out to represent the relation of the reaction time and the yield of M0S2. The crystallization and the average sizes of M0S2 particles prepared under different conditions were also investigated by XRD and TEM. The results showed that the reaction temperature is the primary factor affecting the crystallization and size of particles. Moreover, different reaction systems also play an important role in the size-controlling of M0S2 particles. The average size of M0S2 obtained by Na2S and Na2MoO4 is about 30 nm, however, that by (NH4)2S and (NH4)2MoO4 is about 80 nm.Compared with commercial common M0S2 particles (1.5 \xm in diameter), the tribological properties of the prepared M0S2 nanoparticles were carry out with MQ-800 four-ball tribometer. The results showed that samples containing M0S2 nanoparticles are of better lubricating properties than others containing common M0S2. Moreover, the tribological performances of the mixture of M0S2 nanoparticles and commercial M0S2 particles were also studied, and the results showed the complex in liquid paraffin represents a better lubrication than others samples, especially, a highest extreme pressure can be obtained as the ratio of nano-MoS2 and common M0S2 is about 15 : 85 (wt.%).