Molybdenum Sulfide Powder

Molybdenum Sulfide Powder

MoS2 is distinguished as a lubricating material (see below) thanks to its layered structure and low friction coefficient. The sliding between the layers dissipates energy when shear stress is applied to the material. Extensive work has been done to characterize the friction coefficient and the shear strength of MoS2 in various atmospheres. The cutting resistance of MoS2 increases with increasing friction coefficient. This property is called superlubricity. Under ambient conditions, it was determined that the friction coefficient for MoS2 was 0.150, with a corresponding cut resistance of 56.0 MPa. Direct methods for measuring shear strength indicate that the value is closer to 25.3 MPa.

The wear resistance of MoS2 in lubrication applications can be increased by MoS2 doping with chrome. Micro indentation experiments on MoS2 nanoparticles doped with Cr have found that the elastic limit is increased from an average of 821 MPa by pure MoS2 (from 0 to 0. Cr) to 1017 MPa by 50 to. % Cr. The increase in resistance to elasticity is accompanied by a change in the mode of material breakage. While the pure MoS2 nanopillar fails through a plastic bending mechanism, the fragile fracture modes become apparent when the material is loaded with increasing amounts of dopant.

The widely used method of micromechanical exfoliation has been carefully studied in MoS2 to understand the multilayer flake delamination mechanism. It was found that the exact cleavage mechanism depended on the layer. The thinner flakes of 5 layers are subjected to a homogeneous flex and ripple, while the flakes of about 10 layers are delaminated through the sliding between the layers. The flakes with more than 20 layers showed a torsion mechanism during micromechanical excision. It was also determined that the splitting of these flakes was reversible due to the nature of the van der Waals bond.