Graphite is a traditional solid lubricating material. Due to its special layered crystal structure, graphite material has good lubricating properties. As early as the 1950s, many graphite lubrication products have been developed one after another. For example, the world-famous Leica camera made in Germany used graphite powder as the lubricating material for mechanical parts. In the 1960s, my country also produced bronze oil-impregnated graphite bearings. In recent years, the domestic "Chikai" brand of energy-saving antifriction king additives and "Medron" series lubricants have also come out. Many studies and practices have shown that graphite used in lubricating oil has huge economic benefits and has many advantages of its own. With the development of science and technology and the deepening of scientific research, graphite lubricating materials have been extended to appear in the form of graphite derivatives, such as flake nano graphite, expanded graphite, fluorinated graphite, and elemental or compound intercalated graphite. This article comprehensively discusses the types, dispersion stability and lubricating effect of graphite lubricant additives, and provides references for the development and application of new graphite lubricant materials.

Influencing factors of graphite lubrication effect

Graphite particle size

The lubrication performance of graphite is affected by the particle size. Some scholars have shown that graphite powder with an average particle size of 4~5μm will produce a good lubricating effect, which can minimize the friction and wear of the specimen. However, more scholars have shown that controlling the average particle size below 0.5 µm is the key to the stable suspension of graphite in lubricating oil and also the condition for exerting lubricating performance. Graphite particles are too large to enter between the friction pairs, and cannot isolate and hinder the contact between the two friction surfaces, thus affecting the lubrication performance. However, it is obvious that if the graphite particles are too small to severely damage the graphite layered crystal structure, the friction reduction mechanism of the graphite sheet slip will also be lost, and the graphite lubrication effect is also poor. Therefore, the proper size of graphite particles is the key to graphite's lubricating effect.

The structure of graphite

The structure of graphite is one of the factors affecting the lubricating effect of graphite. Different graphite structures determine different types of graphite. It has not been reported so far that the lubricating effect of expanded graphite, fluorinated graphite, graphite intercalation compound and flake nano-graphite has been compared. It can be seen that under the condition of proper graphite particle size, different graphite types have their own optimal lubricating environment, which is difficult to compare. For example, expanded graphite has a strong absorption capacity and enrichment effect, and it can be mixed with extreme pressure additives to achieve the best effect; when the F/C ratio of fluorinated graphite reaches 1.0, the wear resistance life reaches the best value; and the temperature determines the graphite intercalation The degree of deintercalation of the compound; some scholars have pointed out that as the graphite diameter-to-thickness ratio increases, the specific wear of the lubricated material decreases significantly. It can be seen that the diameter-to-thickness ratio affects the lubricating effect of flake nano-graphite.

External environment

The particle size and structure of graphite are the internal factors that determine the lubricating effect of graphite, and the external environment is the external cause of the lubricating effect of graphite. As early as the 1940s, Robert proposed that humidity is an important factor affecting the lubrication effect of graphite. Water vapor and other small molecules can adsorb on the crystal edges of graphite and invade along the dissociation surface (interlayer), thereby reducing the surface energy of the graphite layer. It makes it easier for graphite to adsorb and form a film on the friction surface, thereby improving the lubricating effect. Bowden et al. also proposed that the friction coefficient of graphite under vacuum conditions increased significantly. Once air was introduced, the friction coefficient decreased rapidly. Therefore, improving the environmental medium of graphite-based lubricating materials is also the key to more effective graphite lubricity. Graphite and graphite derivatives have been widely used in lubricating oil additives and other lubrication fields due to their own good lubrication advantages. However, it is worth noting that the preparation process of ultra-fine and high-purity graphite still requires technological breakthroughs. Graphite nanoization and high-purity industrial production of graphite without sulfur and chlorine will be the future development trend of graphite; at the same time, with the development of technology, the development of new graphite derivative materials such as hollow nanometer will also provide excellent graphite lubrication The agent provides the material basis. It is believed that new graphite lubricating materials will continue to play a more important role for industrial lubrication.

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. Contact us.

Although additives only account for 1% to 20% of the lubricating oil composition, it is precisely because of the presence of additives that the performance of the lubricating oil in a certain aspect is improved, thereby obtaining the desired effect.

What are lubricant additives?

Additives: Compounds used to improve the performance of lubricating oils by adding a small amount of ingredients.

Common additives are: detergents and dispersants, antioxidants, anticorrosives, pour point depressants, antifoaming agents, rust inhibitors, viscosity index improvers, etc.

Viscosity index improvers are the leading products of lubricant additives, accounting for approximately 23.3% of the entire market share in 2015.

Reasons for the appearance of additives:

With the continuous development of the machinery industry and the increasingly stringent environmental requirements, the requirements for the performance of lubricants are also getting higher and higher, which forces the production of additives.

In order to improve the performance of lubricants, in addition to further improving the quality of the base oil, the use and improvement of additives are also indispensable.

The role of oil additives:

1. Give lubricants new properties;

2. Strengthen the performance of base oil;

3. Slow down the speed of bad changes in lubricating oil.

Types of oil additives

1. Additives that improve the physical properties of base oils, such as viscosity index improvers, anti-foaming agents, pour point depressants, etc.;

2. Additives to protect the lubricated surface, such as anti-corrosion agent, anti-rust agent, anti-wear agent, detergent and dispersant, etc.;

3. Additives to protect lubricating oil, such as antioxidants.

In order to improve performance, at least one additive is added to current lubricants, and some lubricants contain more than ten kinds of additives. Such as detergents, which can be used to solubilize polar substances, neutralize acidic substances in lubricating oils, and make some lubricating oils have antioxidant properties; dispersants can prevent the formation of sludge, keep the engine clean, and correct the accumulation of soot. .

Global lubricant oil additives market

The additive market can be divided into four categories:

1. Deposition control additives;

2. Viscosity control additives;

3. Film-forming additives;

4. Other lubricant additives.

Four major international oil additive companies:

Lubrizol (Lubrizol), Infineum (Infineum), Chevron (Chevron Oronite), Afton (Afton)

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. Contact us.

What are the ingredients of lubricating oil?

Lubricating oil generally consists of two parts: base oil and additives. Base oil is the main component of lubricating oil and determines the basic properties of lubricating oil. Additives can make up for and improve the performance of base oils and give some new properties. It is an important part of lubricating oil.

Lubricating oil base oil is mainly divided into three categories: mineral base oil, synthetic base oil and biological base oil. Mineral base oils are widely used and used in a large amount (about 95% or more). However, in some applications, synthetic base oils and bio-oil base oils must be used for blending products, so these two base oils have developed rapidly.

Mineral oil base oil is refined from crude oil. The main production processes of lubricating base oil include: atmospheric and vacuum distillation, solvent deasphalting, solvent refining, solvent dewaxing, clay or hydrogenation supplement refining.

The chemical composition of mineral base oils includes high boiling point, high molecular weight hydrocarbons and non-hydrocarbon mixtures. Its composition is generally alkane (straight chain, branched chain, multi-branched chain), cycloalkane (monocyclic, bicyclic, polycyclic), aromatic hydrocarbon (monocyclic aromatic hydrocarbon, polycyclic aromatic hydrocarbon), cycloalkyl aromatic hydrocarbon and oxygen-containing, nitrogen-containing , Sulfur-containing organic compounds and non-hydrocarbon compounds such as gums and asphaltenes. Biological base oil (vegetable oil) is becoming more and more popular, it can be biodegraded and quickly reduce environmental pollution. Synthetic lubricating oil has the characteristics of excellent low temperature performance, good lubrication performance and long service life. It can be suitable for environments such as high load, high speed, high vacuum, high energy radiation and strong oxidizing media. Since all industrial companies in the world are seeking measures to reduce environmental pollution, and this "natural" lubricant has this feature, although the cost of vegetable oil is high, the increased cost is enough to offset the use of other mineral oils and synthetic lubricants Environmental governance costs caused by oil. According to the nature and processing technology of crude oil, it is classified into paraffin base oil, intermediate base oil and naphthenic base oil.

Why do lubricants need additives?

Lubricating oil base oil possesses some basic characteristics and performance of lubricating oil, but only relying on general processing technology to improve lubricating oil cannot produce lubricating oil with various properties that meet the requirements of use. In order to make up for the defects of certain properties of lubricating oil and give lubricating oil some new excellent properties, various additives with different functions are added to the lubricating oil. The addition amount ranges from a few parts per million to tens of percent.

Adding additives to lubricating oil has two main functions: one is to change the physical properties of the lubricating oil, such as viscosity, freezing point, etc.; the other is to increase or enhance the chemical properties of the lubricating oil, such as anti-oxidation and anti-corrosion. The use of additives in lubricating oil not only meets the requirements of various new machinery and engines, but also prolongs the service life of lubricating oil, reducing the demand for lubricating oil in the proportion of petroleum products.

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. Contact us.

What is lubricating oil additives？

The concept of lubricating oil additives is to add one or several compounds in the lubricant to give the lubricant some new characteristics or improve some of the existing characteristics in the lubricant. Additives are divided into antioxidants, anti-wear agents, friction modifiers, extreme pressure additives, detergents, dispersants, foam inhibitors, anti-corrosion and rust inhibitors, flow point improvers, viscosity index improvers, etc. according to their functions. The additives sold in the market are generally composites of the above single additives. The difference is that the composition of the single additive is different and the ratio of several single additives in the composite additive is different.

GrapheneLubricant Oil Additive

Since graphene was invented and won the Nobel Prize in Physics, everyone has put great expectations on the benefits this new material will bring to mankind. In the past two years, global application research on graphene has become more frequent.

In 2016, after years of research and field testing of thousands of cars, graphene oil additive, the research and development result of polycarbon composites, was announced, which attracted widespread attention in the automotive aftermarket. On January 4, 2017, Polycarbon Composites held a global press conference for the product, which attracted a lot of industry leaders to observe.

The oil additive is added to the car engine oil. Through the oil circulation, it can reach each friction surface in the engine cylinder to enhance the machine's anti-wear ability. In addition, the product can also be firmly attached to the metal surface to repair wear grooves and scratches, forming a layer of "graphene protective film" to isolate direct friction between metals. It can keep the engine of a new car after a period of time as new; let the engine of an old car increase power, save energy and reduce consumption, it is simply another technological revolution in the application of graphene.

Through actual experience and scientific and technological testing, thousands of car owners have confirmed that after adding this graphene oil additive, their car has more power, less noise, no shaking of the steering wheel, and the problem of oil burning has been solved. Fuel consumption and car Exhaust emissions, etc. are significantly reduced.

Relevant experts said that the graphene lubricant additives of polycarbon composites overturned people's existing understanding of traditional automobile oil protective agents. While providing car owners with a good car experience and tangible benefits, it will reduce exhaust hazards and improve the current situation of urban smog, which has social significance beyond the product itself.

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 oil additives, please contact us.

Molybdenum disulfide as a lubricant

Like most mineral salts, MoS2 has a very high melting point but starts to sublime at a relatively low 450°C. This property is useful for purifying compounds. Due to its layered structure, the hexagonal MoS2 is like graphite and is an excellent dry lubricant. It and its cousin tungsten disulfide can be used as a surface coating in mechanical parts (for example, the aerospace industry), two-stroke engines (the type used in motorcycles), and barrels (to reduce friction between bullets and ammunition) ).

Unlike graphite, the lubricating properties of MoS2 do not depend on adsorbed water or other vapors. Its maximum temperature in an oxidizing environment is 350°C, and its maximum temperature in a non-oxidizing environment is 1100°C. Its stability allows it to be used in high-temperature applications where grease is not practical.

It is understood that molybdenum disulfide powder is recognized as the best solid lubricant in the world, but in the application of lubricating oil, because molybdenum is only soluble in aqua regia and boiling concentrated sulfuric acid, and the physical diameter of molybdenum particles is large, it will form in the oil Sediment layering can not be uniformly integrated with the engine oil, so it can only be added to the grease. This makes the manufacture of molybdenum disulfide lubricants a global problem. At present, only a few companies in Germany and the United States have mastered this technology.

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

Analysis of the advantages and disadvantages of molybdenum disulfide as a lubricant

(1) Thoroughly prevent oil leakage, clean and clean, which significantly promotes civilized production.

(2) A large amount of grease can be saved.

(3) Improve the technical operating conditions, extend the maintenance cycle, reduce the labor intensity of maintenance workers, and save labor.

(4) Due to the low friction coefficient of molybdenum disulfide, the frictional resistance between the friction devices is small, which can save electricity. According to the measurement of the brother unit, the power can be held by 12%.

(5) It can reduce mechanical wear, extend the service life of friction equipment, reduce the loss of equipment parts, and improve the attendance rate of the equipment.

(6) The application of molybdenum disulfide lubrication solves critical technology and improves work efficiency and accuracy.

(7) Molybdenum disulfide has the functions of filling and filling, which can restore the geometric dimensions of individual parts and extend the service life.

(8) Molybdenum disulfide has the characteristics of moisture-proof, waterproof, alkali-proof, and acid-proof.

(9) The use of molybdenum disulfide plastic or powder smelted molded parts can save many non-ferrous metals.

(10) After using molybdenum disulfide lubrication in some equipment, the complicated oil supply system can be omitted, which significantly simplifies the structure of the equipment, relatively improves the effective area utilization, and will also cause significant reforms.

(11) Molybdenum disulfide also has shortcomings, such as poor thermal conductivity, low friction coefficient, and low permeability (compared to thin oil). These shortcomings are the main obstacles to expand the scope of use further. On the contrary, industrialized countries attach great importance to the research of solid lubricants and have also held international lubrication conferences to exchange relevant information and discuss new technologies.

Molybdenum disulfide as a superconductor

In addition to its lubricity, MoS2 is also a semiconductor. It is also known that when doped with an electrostatic field, it and other semiconductor transition metal chalcogenides become superconductors on its surface.

Until 2018, the mechanism of superconductivity was uncertain when Andrea C.Ferrari of the University of Cambridge (UK) and his colleagues and the Turin Polytechnic Institute (Italy), reported on Duogufei. The surface of the meter is related to the superconducting state in MoS2. The author believes that this Fermi surface topology will serve as a guide for seeking new superconductors.

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 MoS2, please contact us.

As long as you have bought motor oil, you will know that motor oil is generally composed of two parts, one is base oil and the other is engine oil additive. What kind of relationship do they have? How do they affect the quality of engine oil? In daily life, we often hear the classification of engine oils: mineral engine oil, semi-synthetic engine oil and fully synthetic engine oil. This classification method is based on the processing technology of the base oil used in the engine oil. In fact, engine oil About 80% is base oil, and about 20% is engine oil additive.

Relative to the types of base oils, you may be unfamiliar with oil additives in lubricants. Although base oils are very important, you should know that good lubricants are not good base oils that can bring 100% superior performance. Engine lubricating oil not only plays a role in lubrication, but also needs to bring cleaning, sealing, and anti-rust effects to the engine. No matter how good the base oil is, it cannot perform all functions in every aspect.

First, let us briefly understand the common engine oil additives:

Detergent

When the engine is operated at high temperature, the phenomenon of paint film (Vanish) and carbon deposit (Carbon) will be produced, which must be removed by the detergent in the engine oil, and its composition is metal salts.

Dispersant

When the engine is operating at low temperature, if it is not driven at high speed for a long time, so-called sludge will be produced. To prevent it from being generated, a dispersant must be added to the oil to evenly disperse the sludge in the oil to prevent the sludge from being deposited in the oil filter. On the valve push rod and piston ring, the lubricating oil path is not smooth and the unlubricated parts are chipped and worn.

Anti-Oxidant

Under the high temperature of the engine, the engine oil is especially easy to cause oxidation reaction with the air. After the engine oil is oxidized, the color will deepen and the viscosity will increase, thus increasing the load on the engine. At the same time, the organic acid generated after oxidation will also corrode the engine parts, so the oil is maintained. Oxidation stability is very important, especially in extremely high temperature turbo engines.

Anti-Rust Additive

In order to prevent the metal parts of the engine from rusting, it is of course necessary to add rust inhibitors. The ingredients of this additive contain a polar radical (Polar Radical), which uses the intermolecular polarity to adsorb on the metal surface to protect the metal from air and moisture. And rust due to salt erosion.

Anti-Corrosion Additive

Same as anti-rust additives, but the former is used to protect ferrous metal (Ferrous Metal) parts and the latter is used to protect non-ferrous metal (Non-Ferrous Metal) and alloy (Alloy) parts from corrosion by sulfur and organic acids .

Viscosity Index Improver

The base oil is limited by the nature of crude oil. Its viscosity index can only be improved to a certain extent by the processing technology, and then it must rely on the viscosity index improver. It is also because of the invention of the viscosity index improver that the oil with multiple viscosity can be produced.

Pour Point Depressnat

Pour point depressant is also called pour point depressant. The so-called pour point is to measure the temperature of a certain oil when it starts to not flow, plus 3℃ is the pour point. There will be more or less wax in the oil. (Although the wax has been removed during the refining of the base oil, it still cannot reach 100%). Once these waxes become crystals and solidify at low temperatures, they will prevent the oil from flowing. In order to make the engine start smoothly in winter, it must Inhibitors are added to reduce the pour point, prevent wax from crystallizing, and adapt to cold weather.

Anti-Wear Additive

The so-called boundary lubrication (Boundary Lubrication) occurs when the engine is under high temperature and high pressure, that is, under the condition of high thermal expansion of the metal active surface, the oil film is squeezed apart, and direct friction between metal and metal is formed. In order to prevent In this case, it is necessary to add anti-wear additives. When the additives come into contact with metals, they chemically react, and a protective film is produced to protect the metals from wear when they are in contact with each other.

Anti-Foaming Agent

When the oil is repeatedly stirred in the engine, foam will naturally occur. Where there is foam, where there is no oil film, the engine will lose its protection. On the other hand, where there is foam, it also means that the contact surface with the air increases. It also accelerates its oxidation, so it is necessary to add a defoamer to avoid foam.

Dye

Function 1: For identification, for example, the automatic transmission fluid (ATF: Automatic Transmission Fluid) of automobiles is dyed red to facilitate identification and maintenance in case of oil leakage;

Function 2: For marketing and advertising, for example, most of the two-stroke engine oils in Japan are dyed light blue or red. In addition to being beautiful, it can be used to advertise that the base oil in the lubricant is highly refined and light in color before it is dyed.

What is the formula ratio of Engine oil additive?

In fact, the formulations of all lubricant additives are relatively the same, but slightly different. The formulation of an engine lubricating oil is obtained through many steps such as research, development, and testing, and it takes several years to obtain. For example, some lubricants are specially formulated for urban congestion and often need to be started and stopped. Our fully synthetic extreme protection pays more attention to comprehensiveness and is more suitable for high-temperature engines with turbochargers.

If I use mineral engine oil, should I add a little engine oil additive, such as adding some detergent or anti-rust additive to achieve the effect of fully synthetic engine oil, isn't it more cost-effective?

This is not the case. What is the difference between mineral engine oil and fully synthetic engine oil in base oil? We do not recommend that you buy the engine oil additive by yourself, because the finished engine oil is sold to consumers after strict bench testing and meets the industry specifications and the specifications of major car manufacturers. The formula is the most optimized formula. Add engine oil by yourself On the contrary, additive will affect the efficacy of Castrol oil, and there is a risk of destroying the original efficacy.

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. Contact us.

Thickness of oil film

When it comes to lubrication, what do you think of? It should first produce a thick film to separate the base oil on the two metal surfaces, because the role of lubricating oil is to avoid surface contact between metals. Therefore, under this demand, the oil must be able to provide the ability to separate the friction surface, which requires three supporting factors-relative speed, base oil viscosity and load. These three factors are also affected by temperature, pollution and other factors. When the oil film thickness balances these factors, that is, a viscous fluid film is generated by the relative speed to completely separate the two friction surfaces, and the pressure generated by the fluid film balances the external load, it is called hydrodynamic lubrication.

In applications with rolling contact (negligible relative sliding motion), even with a large local pressure point, it may affect the thickness of the oil film between the metal surfaces. In fact, these pressure points also play an important role. The relationship between the pressure and viscosity of the base oil allows the viscosity of the oil to temporarily increase due to higher pressure. This is called elastohydrodynamic lubrication. Although the oil film will be very thin, it can still produce a complete oil film separation.

In practice, the ideal state of the machine surface is to achieve complete separation, and the thickness of the film is to provide the best protection for reducing friction and wear. But if there are no conditions to meet these oil film thicknesses, such as when the relative flow rate is insufficient, the viscosity is insufficient, or the load is too large, what will happen? In fact, the design and operating parameters of most machines allow insufficient speed, such as when starting, stopping or changing direction. When the temperature is too high, the viscosity will decrease, and excessive pollution will also cause the abrasive particles in the oil film gap to contact.

When the prerequisites for hydrodynamic or elastohydrodynamic lubrication are not met, the base oil will seek support under the so-called boundary contact conditions. This support factor requires the search for additives with friction and wear control properties. Therefore, the base oil and additives are blended together to produce lubricating grease products that meet specific needs, thereby reducing the expected boundary lubrication, and the lubricant has oil film strength and boundary lubrication properties.

The role of oil film

The strength of the oil film is an important factor in addition to the thickness of the oil film to reduce friction and control wear. As mentioned above, in fluid dynamics and elastohydrodynamic lubrication, viscosity is the key to the thickness of the oil film. When the base oil viscosity is not enough to overcome the surface friction between metals, the base oil and additives are required to produce a chemical synergistic effect to form a surface protection mechanism. Under these boundary conditions, boundary lubrication will also be affected by the chemical and physical properties of the mechanical surface and any other environmental factors, so even when the load is heavy, the temperature is high, or the relative surface velocity is low, the oil film strength will be improved. .

Non-lubricated surface interaction

If you observe the mechanical contact surfaces at the molecular level under a microscope, you will find that even though they are processed very smoothly, they are actually relatively rough. This is like an astronaut looking at the earth from a distant space perspective, the earth is a perfectly smooth sphere, while people standing on the surface of the earth see the earth as full of high and low mountains and valleys.

This is because when two metal surfaces are in contact, the actual contact area will be significantly lower than the apparent contact area. From the "microscopic mountain" under the microscope, these contact surfaces are the highest points of unevenness, and the contact rate of low rough surfaces is low. These rough surfaces will undergo elastic deformation due to the corresponding shear strength of the metal. Therefore, the initial contact point first produces elastic deformation, and then more contact points will be connected, and the actual contact area will increase as the load intensity increases.

What is friction?

Friction is the process in which the sliding motion of the interacting surface is subjected to several influencing parameters to produce resistance. Most people think that surface roughness is the main factor in friction. However, when considering that the actual contact area may be less than 1% of the apparent contact area, the actual roughness becomes less important. The cause of friction should be the result of adhesion at the molecular level of rough contact.

How does wear occur?

In the case of insufficient lubricating film thickness on the metal surface, rough contact points may cause cold welding, which is a prerequisite for adhesive wear. The adhesion on these rough points undergoes a hardening process of reinforcement, therefore, the shear point generally occurs at the level below the rough contact point where the metal is not strengthened. As metal shears, the rough tip is either transferred to another surface or broken down into an abrasive particle.

Adhesion is generally considered the initial form of mechanical wear. In addition to the wear of the abrasive grains, there are external sources of wear, causing the abrasive wear to become more destructive. This form of wear is called three-body wear. The two-body wear is caused by sharp surface contact points produced by cutting or planing.

Surface fatigue occurs during rolling contact. The fatigue mechanism comes from the formation of cracks on the working surface or inside the surface layer and growth. High stress under surface rolling conditions can cause fatigue wear.

How to control friction and wear?

The friction and wear control additive is mixed with a small amount of base oil, which has the polarity to promote the adsorption of the metal surface. Due to the interaction conditions, these adsorption forces chemically react with the surface, which is inversely proportional to the conditions that produce sufficient oil film thickness: higher pressure and higher temperature.

When the surface of the machine interacts with higher pressure and temperature, the additive reduces the impact of metal-to-metal contact (wear) by creating a more ductile initial molecular layer on the machine surface. These friction control layers directly reduce the contact process The shear strength becomes a "victim". The initial layer can release the force of the weaker molecular bond of the lubricant and the rough boundary conditions between the metal and the metal to produce a strong bond, thereby reducing friction. The formation of low-shear-strength films is also affected by the type of basic raw materials and mechanical surface metallurgy.

Three types of oil additives help reduce friction and control wear. They are friction modifier, anti-wear additives and EP additives.

(1) Friction Modifier

Polar compounds such as fatty acids added to the base oil, by forming a soap film, reduce friction at low sliding speeds. They are usually used for components that require fuel economy to reduce friction and stick-slip at low speeds, such as in engines or transmissions. They act as anti-wear additives, but are more effective than anti-wear additives at light loads and do not require high temperature conditions. However, when the metal surface reacts more strongly to fatty acids to produce metal soap, the decomposition temperature will be higher.

(2) Anti-wear additives

These polar compounds are usually based on sulfur or phosphorus, such as zinc dialkyldithiophosphate (zinc alkyl dithiophosphate, ZDDP oil additive) type additives, which are developed to chemically react with the metal surface only under boundary conditions. Anti-wear additives are more effective at higher temperatures, where they become more active and produce barrier films. ZDDP oil additive has been widely used for wear protection and can also be used as an antioxidant in oil.

(3) EP Additives (anti-wear additives)

When the surface temperature is too high, the function of friction modifier and even EP additives begins to weaken. EP additives are also based on sulfur and phosphorus, and are the best choice under high temperature conditions. These additives can form soap-like films with low shear strength to react with metal surfaces and can withstand relatively high temperatures. Although this reaction is conducive to the formation of oil film, it may also lead to more chemical corrosion of reactive metals, so be careful.

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. Contact us.

As a new type of dry lubricant, tungsten disulfide WS2 has relatively stable chemical properties and can adapt to too harsh conditions. WS2 can provide maximum protection against wear, rust, and corrosion, and is environmentally friendly. It is non-toxic and will not harm human health or cause pollution to the environment. It can be widely used in the automotive industry to provide Brings many benefits.

WS2 is a layered crystal structure with excellent lubricity and a very low friction coefficient. The dynamic friction coefficient is 0.030, and the static friction coefficient is 0.070. It is coated on the surface of auto parts, which can significantly reduce wear, seizure, etc., eliminate or reduce Equipment repair and maintenance problems caused by friction, wear, etc., improve the working efficiency and service life of auto parts, and save time and cost for users. Here are a few examples of tungsten disulfide applications in the automotive industry.

When the car engine is running, the temperature will be very high, and the piston will rotate back and forth at a very high speed. Operating under such harsh conditions, the piston will accelerate wear. Due to the low friction coefficient of WS2, the lubrication effect can be maintained for parts used for high temperatures or heavy load friction. At this time, coating it on the surface of the piston will reduce wear, lower temperature, and extend service life.

The piston ring is the least durable part of the engine. The piston ring rotates with the piston at high speed and is affected by the high temperature and high-pressure gas in the cylinder. The oil is particularly prone to deterioration at high temperatures, so its wear is severe. With tungsten disulfide coating or tungsten disulfide grease, friction is reduced, and it can move happily with the piston under the conditions of high speed, high pressure, high temperature, and extremely difficult lubrication.

The crankshaft is an essential part of the engine. Its working condition is also high-speed rotation, so it must be able to withstand wear and fatigue. The surface of the journal is generally high-frequency quenched or nitrided. The body is coated with WS2 and finely ground, and its wear resistance and fatigue strength will be significantly improved.

The universal joints, steering knuckles, spring steel plate bushes, and front and rear brake cam bushes in automobiles are relatively challenging to apply oil. The infrequent operation, the lubricating oil used, will deteriorate and lose its lubricating effect. WS2 has excellent mechanical stability and thermal stability, which can guarantee the lubrication effect of these parts and reduce wear.

WS2 has excellent compatibility, water erosion resistance, and affinity with most paints, solvents, and fuels. It can ensure that there is always a layer of the lubricating layer on the surface of the bearing in the water pump and the silicon oil fan clutch and the spiral gear of the driving distributor, to protect against rust and corrosion.

The excellent performance of WS2 is not only used in the automotive industry, but also a wide range of applications, such as the machinery industry, plastics industry, medical device industry, military, aerospace, satellites, aerospace ships, and other high-tech fields.

Other application areas of WS2 nanoparticles

（1） WS2 nanoparticles can be used as an additive for high-temperature grease. After adding tungsten disulfide powder, the fat has excellent properties such as high dropping point, high oil film strength, and low friction factor. It is also used as a colored and black brush additive in the carbon industry. It can also be applied to superhard materials and welding wire materials, as well as to solid lubrication in aerospace (-270℃～1300℃, only WS2 can withstand this temperature in space lubrication), aviation, military, and other fields;

（2）WS2 nanoparticles can replace the application fields of MoS2 and graphite, and have a broader range of uses. Moreover, molybdenum and tungsten are chemical elements of the same family, and tungsten is more massive than molybdenum and has more stable chemical properties;

（3）WS2 nanoparticles are used as a solid additive for lubricating grease. The powder is mixed with lubricating grease at a ratio of 1% to 5%, which can enhance the lubricating performance and high temperature and extreme pressure performance of lubricating grease. In use, ws2 powder is adsorbed on the surface of matching moving parts, which can effectively reduce friction, improve lubricity, drop point and heavy load performance for a long time;

（4） WS2 nanoparticles as a lubricating coating. WS2 powder can be sprayed on the surface of the substrate by dry and cold air under 0.8Mpa (120psi) pressure. Spraying can be carried out at room temperature, and the coating is 0.5 microns thick. In another way, the powder is mixed with isopropanol, and the sticky substance is applied to the substrate. At present, WS2 coating has been used to many fields, such as automobile parts, racing engine parts, aviation parts, bearings, shafts, deep-sea transportation tools, cutting tools, blades, cutters, knives,  high-precision bearings, valve components, Pistons, chains, etc.

Two established ways the tungsten disulfide powder can be used are:
（1） Mixing the tungsten disulfide powder with wet lubricants (such as oil, grease or other synthetic lubricants):
The tungsten disulfide powder can be mixed 1wt% to 15wt% (as required) with grease or oil. This will enhance lubricity of the mixture and also improves High Temperature and Extreme Pressure properties of mixture. During the use, tungsten disulfide powder in the mixture will get coated on mating/moving parts, which in turn reduces friction and improves lubricity and load bearing ability for much longer cycles.

（2）Coating the tungsten disulfide powder on a substrate requiring (dry) lubricant
The tungsten disulfide powder can be coated by spraying (at 120 psi) the substrate with dry (& or cool) pneumatic air. It does not require any binders and spraying can be done at normal room temperature. Coated film will be 0.5 micron thick. In an alternative application method, the powder can also be mixed with isopropyl alcohol and this paste could be buffed to the substrate.

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 contact us.