Preparation and application of tungsten disulfide

Overview of Tungsten Disulfide WS2

Tungsten disulfide is a compound of tungsten and sulfur with a molecular formula of WS2 and a molecular weight of 247.97.

Tungsten disulfide WS2 is a small gray crystal or powder with metallic luster, belonging to the hexagonal crystal system, semi-conducting and diamagnetic. The natural mineral is tungstenite. The layered structure is easy to dissociate and has similar lubricating properties to graphite. Used as a lubricant, such as for aerosols.

Tungsten disulfide WS2 is slightly soluble in cold water and soluble in hot water. It is insoluble in hydrochloric acid and alkali (except for the mixture of concentrated nitric acid and hydrofluoric acid). Soluble in molten alkali, insoluble in alcohol. The density is 7.6g·cm-3. It is reductive and can react with hot concentrated sulfuric acid, nitric acid, aqua regia and other strong oxidants. It can be converted into WO3 by heating in air or oxygen. It is decomposed into tungsten and sulfur when heated to 1250°C in a vacuum. In a dry stream of pure nitrogen, the mixture of tungsten trisulfide and sulfur is heated to 900°C to sublime the excess sulfur, and the residue is tungsten disulfide.

Preparation method of tungsten disulfide WS2

1. Roasting decomposition method:

Tungstic acid reacts with ammonia water under stirring at 57-60°C for 3h, heat preservation and natural sedimentation for more than 16h, and the generated ammonium tungstate reacts with hydrogen sulfide gas to generate ammonium tetrathiotungstate after high temperature roasting and decompose into tungsten disulfide.

H2WO4+2NH3·H2O→(NH4)2WO4+2H2O

(NH4)2WO4+4H2S→(NH4)2WS4+4H2O

2(NH4)2WS4+3O2→2WS2+4NH3+2S+2SO2+H2O

2. Tungsten reacts very slowly with liquid sulfur. WS2 can be formed by passing sulfur vapor to red hot tungsten. Tungsten is mixed with stoichiometric sulphur bloom and reacted in a nitrogen atmosphere at 800°C for 24 hours to form WS2, such as reacting at 6MPa and 1800°C to form orthorhombic WS2.

3. Using ammonium tetrathiotungstate as the raw material, heating and decomposing the ammonium tetrathiotungstate under the condition of isolating the air, the temperature rises from room temperature to 700-1200℃ with a temperature gradient of 100-200℃/hour during heating. After being kept at this temperature for 24 to 48 hours, it is then reduced to room temperature with a temperature gradient of 30 to 110°C/hour, and the material is discharged and crushed.

The preparation method of ultrafine scaly crystal tungsten disulfide used for lubricants has simple process equipment, does not pollute the environment, and is safe and reliable in operation, and can produce tungsten disulfide with stable quality, high purity, and ultrafine crystal structure of hexagonal crystal system.

Advantages of tungsten disulfide WS2 lubrication

1. It has a very low friction coefficient (0.03), high extreme pressure resistance and oxidation resistance (starts to decompose at 450°C in the air, completely decomposes at 650°C, starts to decompose at 1100°C in vacuum, and completely decomposes at 2000°C). It is suitable for lubrication under various harsh conditions such as high temperature, high pressure, high vacuum, high load, high speed, high radiation, strong corrosion, and ultra-low temperature.

2. It has good adsorption capacity on metal surface. It can be added to engineering plastics to make lubricating originals or evenly mixed with some volatile solvents and sprayed on the metal surface to improve the life of the die and the surface finish of the workpiece in the forging process.

3. Tungsten disulfide powder can be mixed with oils and greases to form tungsten disulfide oil, tungsten disulfide ointment, tungsten disulfide wax and other solid lubricating blocks and lubricating films.

Application of Tungsten Disulfide WS2

WS2 tungsten disulfide can be used as a lubricant with better performance than molybdenum disulfide, lower friction coefficient and higher compressive strength. Separately used for high temperature, high pressure, high speed, high load, and equipment operating in a chemically active medium. The forging and stamping lubricants configured with other materials can extend the life of the mold and improve the finish of the product. Filling materials configured with polytetrafluoroethylene and nylon can be used to make self-lubricating parts. In addition, tungsten disulfide can also be used as a catalyst in the petrochemical industry. Its advantages are high cracking performance, stable and reliable catalytic activity, and long service life.

WS2 Tungsten Disulfide Price

The price of WS2 tungsten disulfide will vary randomly with the production cost, transportation cost, international situation, and market supply and demand of WS2 tungsten disulfide. Tanki New Materials Co., Ltd. aims to help various industries and chemical wholesalers find high-quality, low-cost nanomaterials and chemicals by providing a full set of customized services. If you are looking for WS2 tungsten disulfide products, please feel free to contact to get the latest price of WS2 tungsten disulfide.

WS2 Tungsten Disulfide Supplier

As a global WS2 tungsten disulfide lubricant additive supplier, Tanki New Materials Co., Ltd. has extensive experience in the performance, application and cost-effective manufacturing of advanced engineering materials. The company has successfully developed a series of powder materials (the best engine oil additives for nano-diamond, lithium stearate, nano-copper and nano-oil additives), high-purity targets, functional ceramics and structural devices, and provides OEM services.