Disulfide Solid Lubricant Research Articles

Investigating the Fretting of Steel Surfaces in the Presence of Hybrid Anti-Fretting Paste Containing Talc-Graphite-hBN-Molybdenum Disulfide Solid Lubricants

Investigating the Fretting of Steel Surfaces in the Presence of Hybrid Anti-Fretting Paste Containing Talc-Graphite-hBN-Molybdenum Disulfide Solid Lubricants

Thermal and tribological properties of MoS2 doped graphite/copper composites by microwave sintering

The MoS2-doped graphite/copper self-lubricating composites (Gr-MoS2/Cu) were synthesized by a rapid microwave sintering procedure. In this paper, the thermal properties and friction behaviors of Gr-MoS2/Cu composites at room temperature to 200 °C were studied. The doping of molybdenum disulfide solid lubricant into graphite could promote the formation of friction film in the friction process, and optimize the friction and wear properties of graphite/copper composites. Meanwhile, the thermal and frictional properties of the composites at 200 °C are better than those at room temperature. In addition, the influence of the heat dissipation on the friction property of composites was analyzed and studied. The excellent heat dissipation property of the composites effectively mitigated the damage of the friction film and improved the friction property of the composites in the friction process.

Molybdenum Disulfide Solid Lubricant Coating for Ultrahigh Vacuum

Molybdenum Disulfide Solid Lubricant Coating for Ultrahigh Vacuum

Improve Current Collection in the Transport System of the Type "HYPERLOOP"

Background: The vehicle moved in the pipe with rarefied air with the high speed provides high labour productivity, safety, ecological cleanness, comfort and independence from the atmospheric phenomena.
 Aim: improving the current collection in the speed range of 500-700 km/h.
 Method: We develop the method of decreasing the wear of the contact insert by using disulfide solid lubricant.
 Results: of the solution of magnetohydrodynamics equations for the lubricant layer allowed to define the optimal value of the lubricant layer thickness.
 Conclusion: The use of this lubricant is advisable on an alternating current. In this case the wear of the contact insert, the degree of sparking and the electromagnetic noise are decreased.

Addition of molybdenum disulfide solid lubricant to WC-12Ni thermal spray cemented carbide powders through electroless Ni-MoS2 co-deposition

Molybdenum disulfide solid lubricant was added to thermal spray WC-12Ni powders through electroless Ni-MoS2 co-deposition. With varying the concentration of WC-12Ni and MoS2 particles in the plating bath, varied concentration of MoS2 can be controlled in the powder surface layer and the incorporation mechanism of MoS2 into the shell was discussed as well. The thickness of the Ni-MoS2 coatings as well as the MoS2 distribution structure were characterized with a scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS). The phase structure of the co-deposited coatings was characterized with X-ray diffraction (XRD). It is found that MoS2 particles can be co-deposited with Ni to form a Ni-MoS2 composite layer on WC-12Ni powders when effective Ni electroless deposition occurs, since Ni or Ni2+ can encapsulate MoS2 particles to facilitate its incorporation. The content of MoS2 in the coating increases with increasing the concentration of MoS2 in the plating bath, or with decreasing the concentration of WC-12Ni powders in the bath which results in increased thickness of deposited Ni- MoS2 layers. The Ni-MoS2 coated WC-12Ni powders obtained with the electroless co-deposition process can be used for high velocity oxy-fuel spraying (HVOF) with a proper size and adequate fluidity, and are expected to suppress desulfurization and decarburization effectively.

Tribological performance of a tungsten disulfide lubricant film prepared by atomic layer deposition using tungsten hexacarbonyl and hydrogen sulfide as precursors

The tribological properties of a tungsten disulfide solid lubricant film prepared by atomic layer deposition were investigated. The WS2 film was deposited using tungsten hexacarbonyl and hydrogen sulfide as precursors. The results showed that due to the incomplete reaction of tungsten hexacarbonyl, steady atomic concentrations of carbon and oxygen were detected throughout the WS2 film. The friction tests showed that in humid air the WS2 film exhibited good environmental robustness, and in dry nitrogen it exhibited a low friction coefficient, which decreased to 0.035 at a steady lubrication state. The formation of a transfer film on the counterface of a Si3N4 ball, and the reorientation with a few top (002) basal planes in the wear track were revealed.

Tribological properties of dimple-textured titanium alloys under dry sliding contact

Textured dimples are fabricated on the Ti-6Al-4V alloy surfaces by an LD side-pumped solid-state laser. The friction and wear properties of the textured surfaces as well as the relationship between the tribological properties and the texture parameters are investigated by high-speed dry sliding tests. The results show that the dimple-textured titanium surfaces filled with molybdenum disulfide solid lubricants can effectively reduce the friction coefficient as well as its fluctuation compared with the un-textured samples and textured samples without lubricants. The textured surfaces filled with solid lubricants can also reduce the wear loss of the titanium samples and the adhesion on the counterpart steel balls by forming a thin lubricating film at the friction interface. The dimple-distance has a remarkable effect on both the average friction coefficients and the wear rates of titanium surfaces, while the depth of dimple only has an effect on the wear rates within just 90% confidence level. The decrease of the dimple-distance seems to be beneficial to improving the anti-friction and anti-wear properties of the textured surfaces filled with solid lubricants.

Effect of surface texturing on friction properties of WC/Co cemented carbide

An experimental study was carried out to investigate the tribological properties of different surface textured WC/Co cemented carbide. The influence of applied load, sliding speed and area density of textures on frictional performance of surface textured patterns was investigated by Taguchi method. Results show that the textured surfaces filled with molybdenum disulfide solid lubricants can reduce the average friction coefficient, wear rates of Ti–6Al–4V alloy balls and adhesion of Ti–6Al–4V alloy materials on the worn track of cemented carbide compared with un-textured ones. Variance analysis of the experimental data indicates that the area density of textures plays major contribution of both average friction coefficient and wear rate of Ti–6Al–4V alloy balls. Higher area density of textures is beneficial to improve tribological performance of the cemented carbide samples. Sliding speed seems to have no effect on the tribological performance of textured surfaces within the reliability interval of 90%. Applied load has effect on both average friction coefficient and wear rate of Ti–6Al–4V alloy balls at the reliability interval of 95%.

Performance of the self-lubricating textured tools in dry cutting of Ti-6Al-4V

Surface textures were made using laser on the rake or flank face of the cemented carbide (WC/Co) inserts. Molybdenum disulfide solid lubricants were filled into the textured grooves to form self-lubricating textured tools. Dry cutting tests on Ti-6Al-4V were carried out with these self-lubricating textured tools and conventional tool. The machining performance was assessed in terms of the cutting forces, cutting temperature, chip thickness ratio, friction coefficient at the tool–chip interface, and tool wear. Results show that the cutting forces and cutting temperature of the self-lubricating textured tools were reduced compared with that of the conventional tool. The application of the self-lubricating textured tool with elliptical grooves on its rake face can reduce the tool–chip friction coefficient and the chip thickness ratio. The tool life of the textured tools is improved compared with that of the conventional tool. The effectiveness of the self-lubricating textured tools in improving cutting performance is related to the cutting parameter.

An investigation on fretting wear life of bonded MoS 2 solid lubricant coatings in complex conditions

Compared to MoS 2 coatings obtained by magnetron sputtering or ion beam assisted deposition, the MoS 2 bonded solid lubricant coatings has been widely applied in sliding wear due to a cheap technical process and good thickness. However, such coatings technology has been rarely investigated in complex fretting condition. In this work, fretting wear tests of the six novolac epoxy resin bonded molybdenum disulfide solid lubricant coatings have been carried out in various normal loads and amplitudes. The effects of various process preparations, substrate materials, and environmental conditions on the fretting wear life were investigated. Main results show that enhancing substrate hardness, increasing coating thickness, sandblasting substrate surface, and heat curing coating will improve fretting wear life to some extent while it decreases with increasing relative humidity. Oxidation effect is one of the important factors for coating degradation at high temperature.

Lubrication of Mo, W, and their Alloys with H 2S gas admixtures to room temperature air

The in situ lubrication of molybdenum and tungsten using admixtures of hydrogen sulfide to room temperature and pressure air was achieved. Raman spectroscopy confirmed the presence of molybdenum disulfide and tungsten disulfide solid lubricants on elemental molybdenum and tungsten specimens, respectively. Pin-on-disk experiments were conducted with elemental molybdenum, elemental tungsten, and alloys of molybdenum and tungsten in atmospheres containing hydrogen sulfide. Friction coefficients were continuously recorded and comparisons between the sliding friction coefficient in air and in the hydrogen sulfide atmospheres were evaluated. In general, hydrogen sulfide admixtures reduced the friction coefficient for all materials containing molybdenum or tungsten. Friction coefficients for self-mated elemental molybdenum and self-mated elemental tungsten were reduced to μ=0.15 with hydrogen sulfide admixtures to air of 5% and 15%, respectively. In some cases friction coefficients as low as μ=0.08 were recorded.