1. Crystal structure and lubrication mechanism of tungsten disulfide WS2

The crystal structure of WS2 is a typical hexagonal crystal layered structure. Each layer is composed of two layers of hexagonal sulfur atoms sandwiched by a layer of metal tungsten atoms, and sulfur atoms and tungsten atoms form a triangular cone shape. The sulfur atoms and tungsten atoms in each segment are connected by strong covalent bonds, and the layers are combined by relatively weak Van der Waals forces. This kind of connection makes the sheet have a substantial sliding property, and sulfur atoms can quickly form physical or chemical adsorption with most metals to create a transfer film. Friction mostly occurs between the lubricating film and the transfer film, so although conflict alone may not occur Wear, and the damaged part of the film layer can be repaired by moving the lubrication film that adheres to the lubricating material and the WS2 debris accumulated on both sides of the friction part. The SEM electron micrograph of the hexagonal layered sheet-like WS2 is shown below.

2. The characters of tungsten disulfide WS2

WS2, as a solid lubricant has significant characteristics in terms of physical properties. In the past, petroleum base oils and greases were most commonly used as lubricants.

In recent years, with the advancement of industrial technology, the demand for new reliable lubrication has increased with the increase in machine output, rotational speed, sliding speed, load, and use in harsh environments such as high temperature and vacuum. It is also essential to maintain a clean atmosphere and protect the environment.

The oxidation temperature of WS2 is about 100℃ higher than that of molybdenum disulfide (MoS2), which has an excellent heat resistance and extreme pressure performance, and has a low coefficient of friction;

WS2 can resist high surface pressure;

In solid lubricants, its friction coefficient has a tendency to decrease with increasing load;

WS2 also has lubricity at a high temperature of 450℃, which helps prevent sintering or seizure;

WS2 is more resistant to wear;

WS2 can reduce industrial waste and protect the environment;

WS2 has a perfect energy-saving effect;

In addition to reducing energy consumption by reducing the friction coefficient, WS2 can also extend the service life of components, achieve energy saving and reduce costs;

It acts as a lubricant in the temperature range from -273℃ to 450℃ in the air;

WS2 is compatible with most oils and greases;

Compared with graphite, MoS2 and PTFE, WS2 reduces surface deposits by half.

3. Product use examples of tungsten disulfide WS2 

The use of 3-5% WS2 in the brush can effectively extend the life of the brush by 20%-40%; especially suitable for power tools and household appliances, the effect is significant;

The addition of 5-10% WS2 to the graphite mechanical seal ring can effectively reduce the wear rate and extend the life by more than 30%;

WS2 can also be used for mould release agent;

Lubricants for ball bearings and roller bearings;

Engine and driveline components;

Air vibrator, pneumatic motor electrical connector;

Circuit breakers and switches (super electrical contact material additives);

Electric motor

Lubricants for industrial gears and bearings;

Pilot valve, chain saw, etc.;

Rubber gasket, O-ring;

Satellite and aircraft parts;

High vacuum application products;

Cryogenic pump seals, etc.

4. Performance data comparison chart of tungsten disulfide WS2

Although WS2 has a very similar layer structure to graphite and MoS2, its lubricating performance has a particularly special meaning. It has a thicker layer and a more stable molecular structure, which is different from graphite. It is more lubricated under vacuum conditions;

WS2's performance is better than MoS2, and it can continue to lubricate in a wet environment.

Infomak is dedicated to the technology development of special oil additives, combined the Technology of nanomaterials developed dry lubricant and oil additives two series. Our products can significantly improve the performance of lubricating oil, improve energy efficiency, effectively protect the lubrication device and extend the oil change cycle, which can satisfy the lubrication oil constantly upgrading for high-end engine oil additives. 

If you are looking for  WS2, please feel free to contact us.