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Preparation and Application of molybdenum disulfide

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Author : NANOTRUN
Update time : 2021-07-12 09:59:03
Molybdenum disulfide has excellent properties and broad application prospects, so a lot of research has been done on the preparation and application of nano-MoS2 at home and abroad.
 
Natural law
MoS2 can be prepared by the natural method, namely the molybdenite concentrate purification method, which is to remove the acid-insoluble matter, SiO2, Fe, Cu, molybdenite concentrate from high-quality molybdenum concentrate through certain physical and chemical actions. Impurities such as Ca and Pb are further refined to obtain nano-MoS2. The nano-MoS2 made by this method can maintain the natural MoS2 crystal shape, has good lubricating performance, and is suitable for making lubricants. However, the purity of the nano-MoS2 produced by the natural method is not high, and the purification technology needs to be further improved. When the temperature is lower than 400 , it is recommended to use the lower cost MoS2 when working in the ordinary atmosphere. It has a lubricating ability below 1300 , and the lower cost of MoS2 is recommended.
Chemical synthesis
The synthetic method can produce sulfides with high purity, fewer impurities, and fine particle size, and can prepare sulfides that meet different functional requirements. Therefore, the production of nano-sulfides by synthetic methods has always attracted much attention. There are many methods for preparing nano-MoS2, such as ammonium tetrathiomolybdate thermal decomposition method, hydrogen sulfide or sulfur vapor reduction method, high-energy ball milling method, carbon nanotube space confinement method, hydrothermal synthesis method, high-energy physical method and chemical method combination, and many more. Generally speaking, there are two preparation methods. You can directly reach a tungsten source or a molybdenum source with a sulfur source to obtain nano-MoS2, or first react a tungsten source or a molybdenum source with a sulfur source to obtain a precursor, and then pass the precursor through an appropriate Method to decompose or reduce to MoS2.

Application
As a good anti-friction additive, molybdenum disulfide is used in brake pads. The composition of the raw materials of brake pads includes four parts: binder, reinforcing fiber, friction performance modifier, and filler. Among them, friction performance modifiers can be divided into two categories:
(1) Anti-friction material: its addition can improve the material's abrasion resistance, reduce noise, and reduce the coefficient of friction. Such materials mainly include graphite, molybdenum disulfide, lead, copper, and so on.
(2) Friction material: its addition can increase the friction coefficient of the material. Most inorganic fillers and some metals and their oxides fall into this category. The friction performance modifier mainly adjusts the thermal stability of the material and its working stability. 
Molybdenum disulfide has the advantages of good dispersibility, wear resistance, and noise reduction. As a friction performance regulator, the main functions of adding to the brake pad are: 
Anti-friction: Molybdenum disulfide processed by jet pulverization has a particle size of 1.5-20 microns, a friction coefficient of up to 0.05, excellent dispersion performance, and a good anti-friction effect.
Increased friction: When the friction material increases sharply due to the friction temperature, molybdenum disulfide oxidizes to form molybdenum trioxide, which expands with the increase in temperature, which plays a role in increasing friction.
Anti-oxidation and anti-falling: Molybdenum disulfide is slightly acidic. It covers the surface of the friction material to protect other materials from being oxidized, making it difficult to fall off, and has strong adhesion.
Expansion: When the friction material is at a high temperature for braking, many low-temperature materials such as fillers and resins are easily carbonized and burned out, causing the internal voids of the material to increase, but molybdenum trioxide can better compensate.
Reduce the specific gravity: the specific gravity of molybdenum disulfide crystals is 4.5-5.2. As the fineness increases, the specific surface area also increases, and the specific gravity decreases, reducing the brake pads' weight to a certain extent.
 
TRUNNANO (aka. Luoyang Tongrun Nano Technology Co. Ltd.) is a trusted global chemical material supplier & manufacturer with over 12 years’ experience in providing super high-quality chemicals and Nanomaterials. The molybdenum disulfide produced by our company has high purity, fine particle size and impurity content. Please contact us if necessary.
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