Tribological Properties of Mo-S-I Nanowires

Mo-S-I nanowires were synthesized at the Jozef Stefan Institute by chemical transport synthesis. The preparation of these products is described precisely in the patent PCT/EP04/001870. Mihailovic chose the name of nanowires to describe the important length of the sample (of the order of a millimetre) and the absence of cavity in the structure of the wire. A company named Mo6 was created to study the properties of this kind of compound and to market them. These nanowires present, for example, field emission properties [78]. 

Observations by transmission electron microscopy show the presence of some M0S2 sheets in the sample. The XRD technique was used in complement to confirm the presence of 2H-M0S2 in large quantities but not in the pristine material. 

The combination of several analytical techniques proves the presence of some M0S2 sheets in the nanowire sample. Nevertheless, their concentration is low and can be estimated to be lower than 5 %. 

The influence of the nanowire concentration in PAO on the friction was studied using a pin-on-flat tribometer (contact pressure of 0.83 GPa, sliding velocity of 2.5 mm/s, 20 °C, 500 cycles 

With the experimental conditions indicated above, pure PAO presents a high friction coefficient (0.25). The addition of 0.5 wt % of nanowires led to a reduction of 20 % of this value [83]. With 1 or 2 wt % of nanowires, the results are more spectacular. The frictiou coefficient is close to 0.04. This value is usually difficult to reach in a boundary lubrication regime. 

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