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.

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

Molybdenum disulfide is one of the few natural high-quality solid lubricants with a friction coefficient of only 0.05, which is smaller than some other lubricants. Aerospace solid lubricants use specially processed nano-IF-MOS2 (inorganic fullerene structure molybdenum disulfide nanoparticles), which is a non-polar spherical structure composed of 60 molybdenum disulfide molecules, similar to carbon 60 in space The particle size is 40 nanometers, and its extreme pressure and anti-wear ability is twice that of ordinary MoS2!

MoS2 has natural weak alkalinity and excellent antioxidant capacity, which can extend the mileage of engine oil. The regular flow of engine oil can maintain the continuous effect of the MoS2 suspension and reduce the precipitation of molybdenum. The biggest problem with MoS2 suspension is that the particles are non-lipophilic substances, and the particles will precipitate if they are not used for a long time.

The problem of sedimentation of particle suspensions is one of the problems that have not been completely solved in the world today. There are many technologies that claim to solve suspension sedimentation, but there are no relevant patent documents to check.

In order to overcome the suspension problem of MoS2, the second generation of molybdenum lubricant additives-organic molybdenum appeared.

Organic molybdenum is a liquid soluble in engine oil. When the engine is running at high temperature and extreme pressure, it will decompose MoS2 and form a MoS2 film on the cylinder wall to achieve the anti-wear and anti-friction lubrication effect and solve the problem of MoS2 suspension.

But organic molybdenum is easy to oxidize and decompose to produce acidic substances, which will cause the engine oil to deteriorate early, and its chemical properties are not stable. Among them, the useful content of MoS2 is relatively low, and the effect lasts for a short time, so it needs to be supplemented frequently.

Another problem is that ester-based fully synthetic engine oils are very oily and can quickly precipitate various nano-scale suspended particles, including MoS2 suspended particles, and quickly destroy and remove the MoS2 film structure on the friction interface. In the test, it was found that the mixed ester fully synthetic motor oil will quickly sink various suspended particles to the bottom. Therefore, the long-term performance of ester fully synthetic motor oil includes the ability to quickly precipitate particles.

There will be a phenomenon where ester fully synthetic engine oil and solid lubricant compete for the friction interface. It is a fully synthetic ester motor oil, no matter what molybdenum product is used, this is also the functional conflict of the representative products of the two lubrication theories.

Therefore, the choice of MoS2 products should be based on the engine oil used in the car, as well as the focus, not just adding a certain lubricating additive.

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 or organic molybdenum, please contact us.

Friction is a natural phenomenon that exists in the natural world. It is indispensable in people's daily production and life, but at the same time, it also brings unavoidable and unavoidable losses and harms. Friction not only consumes energy but also causes a lot of waste of resources. According to statistics, about one-third of the world's energy is consumed in resistance in various forms, and about 80% of machine parts fail early due to wear and tear.

Friction and wear mainly occur on the surface of friction parts. Adding nano oil additive to automotive lubricants is one of the important methods to reduce surface friction and wear. In recent years, the application of advanced carbon materials in the field of friction has received great attention. Especially with the discovery of rare earth graphite, the research on the application of carbon materials in tribology has entered a new upsurge.

1. What is graphene

Graphene is a new two-dimensional planar carbon material with atomic thickness. In a single-layer graphene crystal, carbon atoms participate in hybridization in the form of sp2, are connected by C-C covalent bonds, and are closely arranged into a two-dimensional honeycomb lattice structure with a six-membered ring the same as the carbon plane in three-dimensional graphite. The theory The thickness is 0.335nm, and the carbon six-membered ring periodic structure can be infinitely expanded in the same plane. It is a nanocrystalline material with macroscopic dimensions. The properties of graphene are closely related to the number of carbon layers. When the number of carbon atom layers of graphite flakes is less than 10, these graphite flakes exhibit different electronic characteristics from ordinary three-dimensional graphite crystals; and when the number of carbon layers exceeds ten layers at most, In addition, the properties of graphene are also closely related to the integrity of its crystal structure.

2 Graphene Lubricant

The friction between graphene layers is affected by various aspects such as stacking form, relative sliding direction, size, defects, layer spacing, and the number of layers. Studies have shown that graphene stacked in the form of incommensurate (lattice mismatch) sliding friction force along the path connecting incommensurate states will be smaller. It is found through an accurate calculation that the friction between graphene layers increases as the distance between the layers decreases. When the graphene layers are stacked in the form of AB, the friction will become more apparent as the distance between the layers increases. Besides, the shape, size, and introduction of the ink can cause frictional changes between graphene layers. The study found that as the number of graphene layers decreases, the friction and sliding friction between graphene layers gradually decreases. When the number of graphene layers reaches 2-3, the viscosity of the graphene layer disappears, and the average friction force is almost zero. Therefore, as a lubricant additive, compared with single-layer graphene, stacked multi-layer graphene is more conducive to the improvement of lubricating performance.

3 Application of graphene in industrial lubricants

Graphene is used as a modifier in industrial lubricants, and it should have good compatibility with base oils to ensure that it can form a uniform and stable dispersion system in industrial lubricants. The surface of graphene oxide contains a large amount of oxygen-containing functional groups, which makes it have excellent hydrophilic properties, so it is difficult to disperse in oil-soluble basic industrial lubricants, and it is prone to agglomeration. In addition, intact graphene has high chemical stability, weak interaction with other media, and great van der Waals gravitational force between layers. It is also difficult to stably disperse in base oils.  In order to effectively exert the lubricating properties of graphene lubricant additive, physical adsorption and chemical modification are mainly used to improve the uniform dispersibility of graphene in industrial lubricants, and uniform and stable graphene are configured with lubricating oil. Compared with the natural graphite sheet, the modification of graphene has a small volume and a thin layer structure, and it is easy to enter the friction contact surface, forming a continuous physical adsorption friction film, preventing direct contact with the surface of the friction pair, thereby modifying the graphene to expand the lubricating oil. It has a lower and more stable friction coefficient, and higher bearing wears resistance.

4 Conclusion

Graphene has shown application value in the field of high-performance lubricants due to its ultra-thin nano-sheet structure, excellent thermal conductivity, self-lubricating properties, mechanical properties, and good chemical stability. As a lubricant additive, it is easy to enter the friction interface and form a stable physical isolation film, which prevents direct contact with the friction surface, thereby enhancing the bearing capacity and extreme pressure and wear resistance of the lubricant. However, due to the large specific surface of graphene, the strong interaction between the carbon layers, the poor interaction with the base oil, and the possibility of agglomeration, it is difficult to stably disperse in the lubricant for a long time, which brings great disadvantage to its application. To better promote the application of graphene in the field of lubricants, more in-depth research work is needed in the following areas:

(1) Study on the compatibility between graphene and base oil. In-depth research on the surface modification technology of graphene, combined with actual industrial production, to achieve low-cost controllable modification of graphene and long-term stable dispersion in industrial lubricants.

(2) Tribological mechanism of graphene in industrial lubricants. An in-depth understanding of the physical and chemical changes that occur on the surface of different friction material materials during the friction process of graphene as a lubricant additive provides a more effective surface modification for graphene.

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 graphene, please contact us.

1. Overview of nanomaterials as oil additive

With the rapid development of science and technology in the 21st century, aerospace, high-speed rail, heavy machinery, and automobile industries have increasingly strict requirements on the service life and reliability of machinery. Mechanical equipment in high load and high speed, friction, and wear under high temperature and the extreme condition is relatively severe, urgent need high-performance lubricant oil. Therefore, prompting lubricant oil quality upgrading, development of excellent anti-wear performance lubricant oil is of significant value. The lubricant base oil in the oil quality is fundamental, oil additive quality and performance is the key to improve the quality of the world's major oil companies to develop new oil additive to improve the quality of the lubricant oil as a development focus.

 With the development of nanotechnology, scientific researchers have applied nanotechnology to the lubrication field. Nanomaterials are widely concerned as lubricant additives, which will give a massive boost to the development of high-performance and high-grade lubricating oil. Nanomaterials refer to the basic unit of materials in which at least one dimension of size is at the nanometer level, i.e., 1-100 nm range. They have the characteristics of small size, considerable surface energy, excellent anti-oxidation stability performance, and so on. Nanomaterials as lubricant additive, the most significant advantage is its tiny sizeable to enter the friction contact area, have good lubrication effect, in addition, the nanometer material has high temperature resistant nonvolatile or breakdown, not easy to react with other additives, satisfy the working condition of high load, high speed, high temperature and extreme inferior demanding conditions using, break through the traditional additives can limit the use of better protection of mechanical equipment.

2. Action mechanism and classification of nano material oil additive

The anti-wear and anti-friction mechanism of nanomaterials are different from that of traditional extreme pressure anti-wear additives. Conventional extreme pressure anti-wear additives contain active groups such as phosphorus, sulfur, and chlorine, which mainly rely on adsorption on friction surface or reaction with the metal surface to form chemical reaction film to achieve anti-wear and anti-friction effect. The action mechanism of nanomaterials mainly creates the following four types: rolling bearing effect, building a protective film, filling and repairing effect, and polishing effect. 

The rolling bearing fact is mainly that the ball, rod, and linear nanoparticles play a rolling and supporting role on the contact surface, changing the pure sliding friction into sliding and rolling resistance.The mechanism of forming protective film mainly depends on the deposition or adsorption of nanoparticles on the friction contact surface during the relative sliding process of the friction surface, and then the formation of physical protective film or interaction with the friction surface to form a chemical protective film to reduce the contact between the friction surface. When the contact surface is damaged, the friction surface will show scratches, ravines, or pits, and the surface roughness will increase. Nanoparticles will be deposited in the surface depression, and the friction contact surface will be leveled to reduce the severity, to achieve the anti-friction effect. The polishing effect mainly reduces the roughness by reducing the micro-convex body of the friction surface through the hard nanoparticles. When a nanometer material is used as a lubricant additive, in addition to the action of the nanometer material itself, the relationship between the nanometer material and the oil film should also be considered. Therefore, the lubrication mechanism should be considered comprehensively.

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.

Graphite powder has a flaky crystal structure and excellent lubricity. And also has good electrical conductivity, thermal conductivity, anti-wear, extreme pressure, temperature resistance (temperature up to 450 ℃) and chemical stability, and other characteristics, so graphite powder is widely used in the machinery industry to make a variety of lubricants.

As lubricant, the graphite powder fine particles are evenly distributed in water, oil, or other media to form a stable gel. It can be directly applied to the parts that need lubrication by rubbing, dipping, or spraying. It can be added to various lubricant and used in combination. It is in contact with the metal surface, not only can form a robust lubricating film, but also improve the wetting performance of the metal surface to other lubricant oil, thereby maintaining long-term lubrication. Besides, because graphite powder exists as pleasant particles, it is easy to penetrate closely matching sliding or rotating parts and play a functional role in lubrication.

Graphite has a hexagonal crystal structure. Because the bonding force between the planes parallel to the base plane is weak, these crystals are natural to shear between the aircraft, that is, the friction is small, and they can support the load perpendicular to the base plane. It has the best properties as a dry lubricant.

Graphite powder, as dry lubricant, can be splash-lubricated in the form of dry powder. It can be used as an additive to make water and oil agents. It can also be combined with other materials to form a composite material for lubrication in transmission — wear-resistant parts.

Graphite powder lubricant can be divided into three types: water agent, colloidal graphite and micronized graphite powder, and its usage is as follows:

(1) Particle graphite powder

Apply directly to the rotating or sliding part, or mix it into the medium, such as kerosene, gasoline or light mineral oil, and phenolic resin or water glass, and spray or dip the part to be lubricated or covered. It depends on needs, generally 10% ~ 20%.

The graphite powder is put into the gearbox, and the powder flies up due to the stirring action of the gear and enters into various friction parts to form dust lubrication. Dust-type lubrication has been applied in the transmission and rear axle differential gearboxes of automobile chassis and has achieved absolute results.

Dust-type lubrication is relatively simple, as long as the solid lubricant powder is poured into the gearbox. During use, the solid lubricant film can be replenished continuously and automatically. And it can run for a long time without manual film protection, and maintenance is relatively simple.

(2) Oil lubricant

It can be directly added to the lubricating oil used in the original lubricating system and used in combination. The amount of use depends on the needs, generally about 2 ~ 10%.

When graphite powder is dispersed in lubricating oil, its lubricity depends not only on the lubricating properties of graphite but also on the performance of the lubricating oil. The test proves that the lubricating film composed of stone tools has the best lubricating performance if it contains 7 to 8 times the amount of lubricating oil of the stone tools. The particle size of graphite dispersed in lubricating oil should be comprehensively considered according to the requirements of use. Generally, 4 to 10 μm particles are often used, because the abrasive wear of 4 to 5 μm is the smallest, and the abrasive wear of 1 μm or less and 150 μm or more is the largest.

(3) Water agent

Graphite powder is directly added to water or emulsified, cutting fluid for use. The amount used depends on the needs, generally about 5-10%.

A suspension of graphite powder dispersed in water, oil, or solvents, commonly used as a lubricant release agent for metal thermoplastic pressure processing. As a friction modifier, graphite can increase the bearing capacity, wear resistance and heat resistance, etc., and has excellent high-temperature adhesion. Graphite milk made of graphite with an average particle size of 10 μm is applied to hot forging, which can be used above 500℃and can be used for forging to 800 ℃ for a short time.

For example, graphite milk is essential in the drawing of tungsten wires. The quality of graphite milk directly affects the quality of tungsten wire (consistent wire diameter and surface defects, etc.) and the wear of drawn diamond die holes. Before pulling, the graphite emulsion is coated on the surface of the drawn tungsten wire in advance and then passed through a heating furnace (the furnace temperature is between 500 and 850 ℃) at a speed of 30 to 70 μm/min. Then the drawing process is completed through a diamond die hole.

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 graphite powder, please contact us.

Friction is standard on two surfaces that are in contact with each other and move with each other. The mechanical motion resistance caused by friction will cause energy loss, as well as surface wear. In severe cases, it will even cause wear and tear of parts and components. At present, about one-third of the world's total energy is consumed by friction. To reduce friction and energy consumption, the world is vigorously developing various lubrication materials. Molybdenum-containing lubricating materials have excellent friction properties due to their ability to form complex Mo-containing lubricant films on friction surfaces and have been widely used worldwide. China is the country with the most significant molybdenum production, and molybdenum production ranks second in the world.

Among the molybdenum type lubricating materials, molybdenum disulfide (MoS2) was the earliest used. MoS2 is a solid lubricant. As the first generation of molybdenum-containing grease, its graphite-like layered structure and weak Van der Waals force between layers make it have excellent anti-friction performance. However, MoS2 is susceptible to precipitation in oil, so it cannot be used as an oil additive. The second and third generation of molybdenum-containing additives is oil-soluble organic molybdenum. This lubricant can dissolve evenly in the oil and stably disperse. It solves the problem of solubility in oil and becomes the ideal oil additive. Among them, the second generation is molybdenum dialkyl dithiophosphate (MoDDP). This organic molybdenum can significantly reduce friction and wear in lubricating oils, reduce wear by more than 50% in base oils, and also in refined oils. It can play a significant anti-wear effect. However, MoDDP contains phosphorus, which causes pollution to the environment and damages vehicle engines. To reduce the toxicity of phosphorus to engine catalysts, in the GF-4 specification issued by the International Committee for Standardization and Demonstration of Lubricants, the phosphorus content is required to be no more than 0.08%. The GF-5 introduced at the end of 2009 introduced a phosphorus volatility test Procedure III GB test puts forward higher requirements for phosphorus content.

For this reason, a third-generation molybdenum lubricant appeared, which was a Molybdenum dialkyl dithiocarbamate (MoDTC) obtained by dephosphorizing and introducing amino groups (NH2) based on the second generation. This organic molybdenum has the function of anti-oxidation and particular anti-corrosion ability while maintaining the anti-friction and anti-wear properties. It can cooperate with other functional additives such as QDDP, detergent, dispersant. Studies have shown that oil-soluble organic molybdenum, as a highly effective lubricant additive, has a better friction reduction effect than the traditional QDD additives. At the same time, with the development of industry and environmental requirements, organic molybdenum additives are also continuously developing towards higher performance and low phosphorus and sulfur.

A large number of experiments have confirmed that organic molybdenum as the friction-reducing anti-wearing agent has strong adaptability, is widely used, can be added to a variety of lubricants and greases, and can be used for various friction pairs. In addition to conventional mineral oils such as 150SN and liquid paraffin, the molybdenum oil additive has excellent performance in synthetic oils such as PAO, polyether oil, and various vegetable oils. In addition to being mainly used in motor oil, it can also be used in rolling fluid In the grease of the vehicle chassis. Organic molybdenum additives have friction-reducing effects on friction pairs of various materials, such as alloy steel, phosphor bronze, and different diamond-like coatings.

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.

Lubricating oil by base oil and engine oil additives, commonly used lubricating oil lubricant additives according to its function, can be divided into detergent, dispersant, antioxidant, anti-wear agent and a friction modifier, etc. Engine oil additives can improve the performance of some of the internal combustion engine oil, such as clean dispersion properties, oxidation resistance, and anti-wear performance, etc., to meet the high load and high power internal combustion engine requirements for domestic combustion engine oil. Different engine oil additives in lubricating oil interactions, some interaction needed to make nature were strengthened, called a synergistic effect. Some interactions weaken the required properties and are called antagonistic impact.In the formulation of lubricating oil, the synergistic effect between additives should be made as far as possible to avoid the antagonistic impact, to reduce the number of additives, and improve the quality of lubricating oil.

Dialkyl disulfide generation of zinc phosphate (ZDDP) is a kind of multiple effect additive, anti-wear, antioxidant, corrosion resistance and performance, and it can effectively prevent engine bearing corrosion due to the high-temperature oxidation and make the oil viscosity increase, is one of the most commonly used lubricating oil lubricant additives, also is a kind of significant influence the properties of lubricating oil anti-wear lubricant additives.ZDDP oil additive is by far the most successful lubricant additives.ZDDP since the 1940 s to successful development, it has been as a kind of efficient lubricant additives used today.ZDDP oil additive is an indispensable additive in engine oils.

Other lubricant additives and ZDDP oil compound with action research

Organic molybdenum friction modifier has excellent anti-friction properties but also has specific anti-wear properties and antioxidant properties. The commonly used organic molybdenum friction modifier in internal combustion engine oil mainly includes molybdenum dialkyl dithiophosphate (MoDTP) and molybdenum dialkyl dithiocarbamate (MoDTC). The combined use of MoDTC and ZDDP results in a synergistic effect and significantly improved wear resistance. However, there is no apparent synergistic effect between MoDTP and ZDDP.

Different detergents and ZDDP have different effects on the wear resistance. Calcium sulfide alkylphenol and magnesium salicylate combined with ZDDP improved the wear resistance of oil. In contrast, calcium alkyl salicylate of medium alkali value and magnesium sulfonate of high alkali value combined with ZDDP decreased the wear resistance of oil. The dispersant of succinimide increased the chemical activity of ZDDP so that the surface reaction was more comfortable to carry out at the same temperature, and the reaction surface film generated at the same time had better temperature tolerance. The combination of succinimide and ZDDP improved the anti-wear performance of the oil. Motor oil with zinc-containing different types of dispersants had a different anti-wear performance. Oil containing polymer succinimide had the best anti-wear performance, followed by oil containing monosuccinimide, and oil-containing boride succinimide had the worst anti-wear performance. The combination of organic molybdenum anti-friction agent and ZDDP can improve the anti-wear property of oil. The improvement of wear resistance of organic molybdenum friction modifier and ZDDP compound was also related to their relevant content.

ZDDP oil is added as an antioxidant oil, so why are antioxidants added to lubricants?

With the rapid development of machinery industry and high-end equipment manufacturing industry, the use of ZDDP series and other antioxidant and anti-corrosion agents has been unable to meet the antioxidant performance requirements of high-end lubricants, and a variety of excellent shielding phenolic, amine, heterocyclic and other new ash-free antioxidant additives research and product applications develop rapidly.

What is the reason for the addition of antioxidants to lubricating oil?

Engines fueled by fuel oil, kerosene, gasoline, natural gas or human-made gas, liquefied gas, etc. must use lubricants (such as paraffin-based lubricants) to lubricate their moving parts. Lubricating oil in use to contact with air, all kinds of machinery and equipment will generate heat, make the friction parts operation temperature, besides, the apparatus of all types of metal material, such as copper, iron, etc. all can play a catalytic role in accelerating the oxidation of oil, is ultimately lubricating oil viscosity increased, generate acid corrosion of metal material, also makes a variety of carbon precipitation form or shape of asphalt material such as film block pipeline. All these changes have adversely affected the continued use of oil products and the regular operation of equipment. Therefore, oil is required to have a better antioxidant and anti-corrosion effect. The purpose of adding anti-oxygen and anti-corrosion additives to oil products is to inhibit the oxidation process of oil products, the catalytic effect of passivation metal on oxidation, and to prolong the use of oil products and protect the machine.

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.