Ultrafine WS2 powder is a new type of lubricating and anti-wear material with excellent lubricating properties and its dry friction factor is only 0.03. Tungsten disulfide is one of the best raw materials for friction lubrication in the scientific community. Under static conditions, its dry friction factor is 0.07. Under dynamic conditions, the dry friction factor is only 0.03. Dry friction performance is better than other materials, and can be used under high temperature and high pressure. In the atmosphere, tungsten disulfide has an operating temperature range of -270 °C to 650 °C (-450F to 1200 F); in vacuum, its temperature range is -188 °C to 1316 °C (-305F to 2400F). The extreme pressure capability of the tungsten disulfide coating is very high, reaching 2000Mpa (300,000 psi). In the solid lubrication of the aerospace industry, only WS2 can withstand the high temperature of the universe from -270 °C to 1300 °C. Therefore, tungsten disulfide has been used as a high-grade, high-performance friction lubrication material in NASA's aviation, aerospace, military and other high-tech fields.

2. Lubrication mechanism of tungsten disulfide

The good lubricating performance of WS2 is because: microscopically, the microstructure of tungsten disulfide crystal is a lamellar hollow sphere with hexagonal system, and its surface is formed into a hexagonal network with S-W-S molecular clusters. Connected by Van der Waals force, this weak bond is easily sheared between layers and exhibits a low coefficient of friction. At the same time, the tungsten disulfide crystal is very stable at high temperatures. Even at temperatures above 550 °C, WS2 can form a dense tungsten oxide (WO3) protective layer by slow oxidation to suppress further oxidation of WS2, and tungsten oxide is also It has a very low friction factor and can still protect the metal surface from gluing.

3. Performance comparison between tungsten disulfide and molybdenum disulfide and graphite

Tungsten disulfide has excellent lubricity under heavy load, vacuum and high temperature. The following characteristic table shows that tungsten disulfide has excellent thermal stability and oxidation resistance at high temperatures, and tungsten disulfide has a thermal stability higher than that of molybdenum disulfide by 93 ° C (200 ° F), and when the load is increased, The friction coefficient of tungsten disulfide is reduced.

Comparison of physical and chemical properties of WS2 / MoS2
Note: PSI=6.89×103Pa
Comparison table of average friction factor μ and wear scar diameter (mm) of WS2 and molybdenum disulfide and graphite

Here are some examples of existing tungsten disulfide applications.

1) Tungsten disulfide powder is used as a solid additive for lubricating grease. The powder is mixed with lubricating grease at a ratio of 1% to 15% to enhance the lubricating properties and high temperature extreme pressure properties of the lubricating grease. In use, the tungsten disulfide particles are adsorbed on the surface of the mating/moving member, which can reduce friction, improve lubricity, increase the dropping point and enhance the heavy load performance for a long time.

2) Tungsten disulfide powder as a lubricating coating The tungsten disulfide powder can be sprayed on the surface of the substrate by dry cold air under a pressure of 0.8 MPa (120 psi). Spraying can be carried out at room temperature with a coating thickness of 0.5 microns. Alternatively, the powder is mixed with isopropyl alcohol to apply the viscous material to the substrate. At present, tungsten disulfide coating has been applied in many fields, such as automotive parts, racing engine parts, aerospace parts, bearings, shafts, deep-sea vehicles, cutting tools, blades, cutting tools, knives, demoulding, high-precision bearings, Valve components, pistons, chains, etc.

In addition, tungsten disulfide is also used as a colored brush in the carbon industry, and can also be applied to superhard materials and wire materials. Tungsten disulfide can completely replace molybdenum disulfide, and the price is equivalent, the quality is better, and the performance is stronger. Moreover, due to the extremely low coefficient of friction of tungsten disulfide powder (0.03 under dynamics and 0.07 under static conditions), its application field is infinitely broad, and everything is possible as long as it is desired.

Introduction of SAT NANO WS2 powder

The product production technology is mature, the quality is stable, WS2 purity ≥99.9%; W=73.5～74.3wt%; S=25.82～26.5wt%, particle size: first grade Fsss=0.4～0.7μm, second grade Fsss=0.85～1.15μm; It adopts inner double-layer vacuum packaging, external metal barrels, 50 kg or 25 kg per barrel; it can be produced and packaged according to user requirements. Uses: WS2 ultrafine powder is a new type of lubricating material with excellent lubrication properties. It can be used as an additive for high-temperature grease. After adding WS2 powder, the grease has excellent properties such as high dropping point, high oil film strength and low friction factor. Also used as a colored, black brush additive in the carbon industry

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