Application characteristics of molybdenum disulfide MoS2

What is molybdenum disulfide?

Molybdenum disulfide is the main component of molybdenite. Black solid powder with metallic luster. The chemical formula is MoS2, the melting point is 1185 ℃, the density is 4.80g/cm (14 ℃), and the Mohs hardness is 1.0 -1.5.

Molybdenum disulfide lubrication mechanism

Molybdenum disulfide can be adsorbed on the metal surface (note that the metal is mentioned here, and the plastic is generally made of polytetrafluoroethylene) to form a lubricating film, which plays a lubricating effect when the lubricating film is broken.

Molybdenum disulfide and lubricant adhere to the friction pair and form a stronger connection (chemical affinity or physical embedding) than the lubricant.

Characteristics of molybdenum disulfide

When used in a humid environment, molybdenum disulfide may cause electrochemical corrosion of metals. In a low temperature and humid environment, the performance of molybdenum disulfide will be affected.

Graphite can also be used as a solid additive, but compared with graphite, the friction coefficient of molybdenum disulfide is much smaller than that of graphite, so the frictional resistance caused is smaller. At high temperatures, molybdenum disulfide will oxidize to form molybdenum trioxide which has no lubricity.

Under dry, high temperature, and vacuum conditions, it can give full play to the performance of molybdenum disulfide.

In the presence of a high concentration of oxygen, the oxidation rate of molybdenum disulfide increases and becomes molybdenum trioxide. In the air, below 300 ℃, the oxidation rate of molybdenum disulfide is very slow and its properties are very stable. Above 400 degrees Celsius, molybdenum disulfide slowly begins to oxidize to form molybdenum trioxide. After that, the higher the temperature, the more severe the degree of oxidation and the rate of oxidation, reaching about 600 degrees Celsius. Molybdenum disulfide is rapidly oxidized in the air. In addition to humidity and temperature, particle size also affects the rate of oxidation of molybdenum disulfide. Under the same conditions, the finer the powder, the faster the oxidation rate. Although molybdenum trisulfide has no lubricity, it will not cause obvious wear on the metal friction surface. Therefore, after molybdenum disulfide is partially oxidized to molybdenum trisulfide,

Molybdenum disulfide begins to decompose at 1370°C, with a melting point of 1700°C.

In environments with high humidity and contact with water, molybdenum disulfide can cause metal corrosion. The use of additives can inhibit corrosion to a certain extent. However, if the lubricating surface is subjected to extremely high pressure, the performance of the anti-corrosion additive may also fail.

Although molybdenum disulfide itself is a lubricant, it is a solid after all. Adding to grease will reduce the smoothness of the grease and increase friction to a certain extent. Therefore, for general load equipment, if molybdenum disulfide lubricating oil (extreme pressure lubricating oil/grease) is not necessary or required, it is not recommended. Molybdenum disulfide is suitable for heavy loads and low speeds, producing a large amount of boundary lubrication.

Overview of molybdenum disulfide

Molybdenum disulfide is an inorganic substance with the chemical formula MoS2,which is the main component of molybdenite.Black solid powder with metallic luster,Molybdenum disulfide is an inorganic substance with the chemical formula MoS2, which is the main component of molybdenum ore. Black solid powder, with metallic luster, smooth to the touch. The specific gravity is 4.8, and the Mohs hardness is 1 to 1.5. In general, the friction coefficient is 0.05~0.09. The oil absorption value is 1~1.5. Melting point is 1185℃, sublimation at 450℃. In the atmosphere, the temperature starts to oxidize gradually at around 400°C, and as the particle size becomes finer, the oxidation temperature gradually decreases, and the oxide is molybdenum trioxide. It does not dissolve in dilute acid, alkali, solvent, petroleum, synthetic grease. It can be corroded by aqua regia, concentrated sulfuric acid and boiling concentrated hydrochloric acid. Strong chemical and thermal stability. It does not chemically react with general metal surfaces and does not corrode rubber materials.

Application of molybdenum disulfide

Molybdenum disulfide is an important solid lubricant, especially suitable for high temperature and high pressure.It is also diamagnetic,can be used as a linear photoconductor and a semiconductor showing P-type or N-type conductivity,and has the functions of rectification and energy conversion.Molybdenum disulfide can also be used as a catalyst for the dehydrogenation of complex hydrocarbons.

It is also known as the"king of advanced solid lubricants."Molybdenum disulfide is a solid powder made from natural molybdenum concentrate after chemical purification and then changing the molecular structure.This product is black with a slight silver gray,metallic luster,slippery to the touch,and insoluble in water.The product has the advantages of good dispersibility and non-sticking.It can be added to various greases to form a non-sticky colloidal state,which can increase the lubricity and extreme pressure of the grease.It is also suitable for high-temperature,high-pressure,high-speed and high-load mechanical working conditions to extend equipment life.The main function of molybdenum disulfide used in friction materials is to reduce friction at low temperatures, increase friction at high temperatures,and have a small loss on ignition.It is volatile in friction materials.

Anti-friction: Molybdenum disulfide processed by supersonic jet pulverization has a particle size of 325-2500 mesh, micro-particle hardness of 1-1.5,and friction coefficient of 0.05-0.1,so it can reduce friction when used in friction materials;

Increase friction: Molybdenum disulfide is not conductive,and there are copolymers of molybdenum disulfide, molybdenum trisulfide and molybdenum trioxide.When the temperature of the friction material rises sharply due to friction, the molybdenum trioxide particles in the copolymer expand as the temperature rises to increase the friction;

Anti-oxidation: Molybdenum disulfide is obtained through chemical purification and comprehensive reaction.Its PH value is 7-8,which is slightly alkaline.It covers the surface of the friction material to protect other materials and prevent them from being oxidized,especially to make other materials not easy to fall off and enhance the adhesion;

In addition,molybdenum disulfide can also become a new material for making transistors.Compared with graphene,which is also a two-dimensional material,molybdenum disulfide has an energy band gap of 1.8 eV,while graphene does not have an energy band gap. Therefore,molybdenum disulfide may have a broad application space in the field of nano-transistors.Moreover,the electron mobility of a single-layer molybdenum disulfide transistor can reach up to about 500 cm^2/(V•s),and the current switching rate can reach 1×10^8.

The price of molybdenum disulfide

The price of molybdenum disulfide varies randomly with production costs, transportation costs, international conditions, exchange rates, and the supply and demand relationship in the molybdenum disulfide market. Tanki New Materials Co.,Ltd aims to help all 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 molybdenum disulfide materials, please feel free to contact to get the latest price of molybdenum disulfide.

Suppliers of molybdenum disulfide

As a global molybdenum disulfide 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 (zinc sulfide, tungsten sulfide, bismuth sulfide, etc.), high-purity targets, functional ceramics and structural devices, and provides OEM services.