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1.The distribution area of molybdenum concentrate
According to statistics in 2018, global molybdenum reserves are about 17 million tons, of which nearly 50% are located in China, while the United States, Chile, and Peru together hold 39% of global molybdenum reserves, and the rest are scattered in other countries.
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2.What is the accompanying situation of molybdenum concentrates everywhere
1. Most of the molybdenum mines in the Americas are copper-molybdenum associated mines. Usually, copper is extracted first, followed by molybdenum. Usually the CuO content in molybdenum disulfide (MoS2) is an important indicator.
2. Henan Luanchuan Molybdenum Mine is mostly associated with tungsten and molybdenum.
3.The Fe content of molybdenum concentrate from Jilin province is relatively high, and the production of MoS2 requires high-temperature roasting.
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3.What is the difference between MoS2, WS2 and graphite
The base oil will slowly volatilize at a high temperature above 200°C, and graphite will adhere to the lubricating surface to form solid lubrication. It is specially used for the lubrication of high-temperature friction parts and bearings under heavy load/impact load or humid/polluted environments to provide maximum anti-rust and anti-rust Corrosion protection Moly Grease's anti-wear, extreme pressure and lubricating properties are much better than graphite grease. Molybdenum disulfide grease is better than graphite grease when used in some harsh, heavy-loaded gears and bearings, and parts with impact loads. The friction factor is slightly lower than MoS2, and the thermal stability is higher; for special conditions For the sliding friction parts under the application of WS2, it can exert a better effect than MoS2.
Under normal temperature conditions, the WS2 coating is not as good as the MoS2 coating on the metal substrate. Under high temperature conditions, the WS2 coating has a stable friction factor and better friction performance than the MoS2 solid lubricating coating.
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4.What are the factors affecting the color difference of molybdenum disulfide (MoS2)
1. Origin: The molybdenum disulfide (MoS2) produced by molybdenum concentrates from different origins will be slightly different. The materials in some production areas are grayish, and the materials in some production areas are darker, but the whole is gray-black, and it has a silvery luster when it is opened with fingers. If the material is pure black and there is no silver metallic luster when it is twisted by hand, it may be a fake (such as graphite doped or molybdenum disulfide pretending to be graphite)
2. Particle size: The color of molybdenum disulfide (MoS2) with different particle sizes is also slightly different. Molybdenum disulfide (MoS2) with a finer particle size (such as <3um) is grayish due to the larger specific surface area of the particles and more light is refracted; molybdenum disulfide (MoS2) with a larger particle size (such as 20um) is blackish due to the particles The specific surface area is relatively small, and the refracted light is relatively small.
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5.The relationship between Fisher particle size and laser particle size
Fischer particle size: Fischer particle size analyzer is also called average particle size analyzer, which is measured by air penetration method. It is based on the difference in height h between the two pipes of the pressure gauge caused by the pressure difference caused by the air passing through the powder bed to obtain the specific surface area and average particle size of the particles.
When measuring, the best porosity should be found first, and then the particle size of the powder should be measured under the best porosity. Use a powder sample to start with a higher porosity and gradually compact the powder. Depending on the powder compressibility, take a different porosity interval of 0.005 to 0.05. Press once and measure the particle size once until it can't move. The optimal porosity is the average value of the porosity corresponding to the two nearest particle size values.
The relationship between the average particle size and its specific surface area is: average particle size = 6000/volume specific surface area
Laser particle size: The laser particle size distribution meter measures the size distribution of the particle group.
There is no necessary relationship between the Fisher particle size and the laser particle size. When the particles in the particle group are all spherical in an ideal state, the Fisher average particle size = D32 (surface area average diameter) in the laser particle size distribution data.
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6.Is the purity of molybdenum disulfide the higher the better? Is the particle size finer the better?
The purity and particle size of MoS2 used in the product are related to the formulation of the product and the compatibility with other raw materials. It is not that the higher the purity and the finer the particle size, the better, the suitable is the best.
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7.Factors affecting the oxidation of molybdenum disulfide
1. Temperature: Molybdenum disulfide starts to oxidize slowly at 400℃, and its oxidation product is molybdenum trioxide. The higher the heating temperature, the greater the oxidation amount; the longer the heating time at a certain temperature, the greater the oxidation amount.
2. Particle size: The oxidation amount of molybdenum disulfide is also closely related to its particle size. The smaller the particle size, the greater the oxidation amount at the same time at a certain temperature.
3. Humidity: Humidity also has a great influence on the oxidation of molybdenum disulfide. Molybdenum disulfide is gradually oxidized at a certain temperature, and the participation of water can promote the oxidation of molybdenum disulfide.
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8.Molybdenum disulfide's temperature and its influence on the lubricating properties of molybdenum disulfide
The oxidation temperature of molybdenum disulfide (MoS2) is 400°C, the friction coefficient is reduced at 800°C in a vacuum environment, and the melting point is 1185°C. Molybdenum disulfide starts to oxidize at 400°C, and becomes significant at 450°C. It oxidizes sharply at 540°C. The final products of oxidation are molybdenum trioxide and sulfur dioxide. Molybdenum trioxide will increase friction. It still has Lubricity, after the formation of molybdenum trioxide, the friction coefficient increases.
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9.What are the factors affecting the life of molybdenum disulfide lubricating coatings?
Whether the lubricating effect of molybdenum disulfide is satisfactory depends to a large extent on its use conditions and use environment. For example, the physical properties of the surface of the substrate, temperature, relative sliding speed, load size and movement mode will affect its lubrication life.
1. The surface roughness of the substrate will affect the adhesion ability of the film and also the thickness of the film. If the film is too thick or too thin, it is not conducive to lubrication. In addition, the working surface should be strictly free of rust, stains, oxides and other impurities.
2. Too high temperature may change the properties of the film and change the lubricating performance.
3. The higher the sliding speed, the higher the temperature, which reduces the lubrication life of the film.
4. The greater the load, the greater the contact stress, and the matrix will produce greater elasto-plastic deformation, which exceeds the deformation capacity of the film and breaks.
5. Movement methods include continuous rotation and swing. Generally speaking, under the same other conditions, continuous rotation has longer lubrication life than swing.
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10.After adding molybdenum disulfide to the product, why the effect is not much different?
In order to reduce costs, many businesses use graphite and other lubricating additives. In the actual use of the terminal, because graphite and other products are also lubricating materials, they have the same performance as molybdenum disulfide in some environments, plus many products They are all consumables, and customers can't detect the difference in actual effect because they change frequently during use.
However, under special circumstances and extreme environments, the performance of molybdenum disulfide can be highlighted. This is why many well-known manufacturers have high prices for formula products involving molybdenum disulfide, but the performance is guaranteed.
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11.Why do some test reports of molybdenum disulfide products add up to more than 100%
The test items of molybdenum disulfide are tested according to the national standard GB/T23271-2009. Most of the items are calculated by chemical methods. The allowable analysis errors of the national standard are not equal. Strictly speaking, if you exclude all For factors such as analysis error and human error, the sum of all contents must be equal to 100%.
In other words, the national standard method is to add up individual items to get the result. The ICP of the equipment tested abroad is 100% minus a single item to get the result. Therefore, the two methods can only see the consistency from the trend, but they are not comparable.
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