The Difference Between Tungsten Disulfide WS2, Molybdenum Disulfide MoS2 and graphite-Knowledge-Dry Lubricant And Oil Additives Suppliers

The Difference Between Tungsten Disulfide WS2, Molybdenum Disulfide MoS2 and graphite

2021-01-15 14:03:04  Knowledge

Tungsten disulfide WS2, molybdenum disulfide MoS2, and graphite are all two-dimensional layered materials, all of which have excellent optical, electrical, magnetic, mechanical and thermal properties, and are therefore popular among researchers in many fields. For example, in the field of energy storage, tungsten disulfide, molybdenum disulfide and graphite can all be used to produce lithium-ion battery anode materials, but due to their different physical and chemical properties, the performance of the prepared products also varies. The main differences are the capacity, thermal stability, charge and discharge rate performance of the material.

In addition to the performance differences in the table, their lubrication performance, production process, coating application and other aspects are also inconsistent.

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Lubrication performance

Graphite: The base oil will slowly volatilize when the temperature is above 200℃ or high temperature, and graphite will form solid lubrication, which is specially used for the lubrication of high temperature friction parts and bearings under heavy load/impact load or humid/polluted environment, and provides maximum Rust and corrosion protection.

Molybdenum disulfide MoS2: Moly Grease containing molybdenum disulfide (Moly Grease) has superior anti-wear, extreme pressure and lubricating properties than graphite grease. In some harsh, heavy-duty gears and bearings, and parts with impact loads, the effect of using molybdenum disulfide grease is better than using graphite grease.

Tungsten disulfide WS2: The friction factor is slightly lower than that of MoS2, and the thermal stability is higher; for sliding friction parts under special working conditions, the application of WS2 can exert its better effect than MoS2.

Production process

Artificial graphite: powdered high-quality calcined petroleum coke is used as the main raw material, bitumen is added as a binder, and a small amount of other auxiliary materials are added; after the various raw materials are matched, they are pressed into a shape, and then non-oxidized at an appropriate temperature Treat it in a mild atmosphere to graphitize it to obtain artificial graphite.

Molybdenum disulfide: it can be prepared by natural method, namely molybdenite concentrate purification method, which is to remove the acid insoluble matter, SiO2, Fe in molybdenite concentrate through certain physical and chemical action of high-quality molybdenum concentrate , Cu, Ca, Pb and other impurities, and then further refined to obtain nano-MoS2.

Tungsten disulfide: Tungstic acid reacts with ammonia water under stirring at 5760℃ for 3 hours, keeps warm and naturally settles for more than 16h, and the generated ammonium tungstate reacts with hydrogen sulfide gas to generate ammonium tetrathiotungstate after high temperature roasting and decomposition into Tungsten disulfide.

Coating application

Under normal temperature conditions, WS2 coating is inferior to MoS2 coating on the metal substrate; under high temperature conditions, the friction performance of WS2 coating is worse than MoS2 solid lubricating coating.

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