Why sulfur-content EP antiwear additive is widely used for lubricant oil？
Leave a message
In the boundary lubricant, heavy loading, high speed, or impulse load, if the lubricant oil is insufficient for extreme pressure, the oil film on the metal's surface is easily broken up, which will lead to the direct connection of metals, severe wear and friction, and even sintering. It eventually results in equipment failure.
The sulfur carrier lubricant EP additive can form a highly intense protective film and provide anti-wear and anti-friction protection.
The core mechanism of sulfur-containing EP antiwear additive
EP antiwear agent is an additive that prevents the sintering, abrasion, and wear of metal surfaces under extreme pressure conditions.
- The core mechanism of the sulfur carrier additive
- A sulfur carrier additive adsorbs on the metal surface, reducing friction between the metals.
- With the increase in load, the temperatures of the connection points between the metals will rise instantly. The organic sulfur sulfides first react with metals to form a ferrous sulfide coating (the S-S bond breaking) to provide antiwear protection for the metals.
- With the further increase of load, the C-S bond begins to break and form a solid ferrous sulfide film, providing extreme pressure to the metals.
The unique features of sulfur-content EP antiwear additive
Excellent extreme pressure performance: sulfur carrier additive can form a ferrous sulfide film under high temperatures, with a tense structure and a higher melting point. The carrier sulfide additive can maintain the solid lubricant layer at high temperatures of 750℃, preventing metal-to-metal contact and providing reliable protection under extreme pressure.
Strong ability to anti-sintering: sulfrization lubricant oil film tightly contacts the metal surface, and is resistant to fracture or spalling under high temperatures and high pressures, which can inhibit the local welding and adhesion. It can ensure the equipment operates smoothly under high-speed and high-torque conditions.
Limitation:
Sulfur-carrier agent has a poor anti-wear performance, and the content of active sulfur will accelerate the wear. In practical application, the sulfur content antiwear additive is not used alone; it is compatible with other additives.
The different types of extreme-pressure antiwear additives
The extreme pressure agents mainly include: sulfur-containing extreme pressure antiwear agents, phosphorus-containing EP anti-friction additives, chlorine-containing extreme pressure antiwear agents, organic metal salts, and borate extreme pressure anti-wear agents. Currently, the most commonly used lubricants are sulfur-containing extreme pressure anti-wear agents and phosphorus-containing extreme pressure anti-wear agents.
- Chlorine-containing agents are useful under conditions of no water, and the temperature is under 350 ℃, which has a most failure is it's toxic and environmentally harmful.
- The extreme pressure performance of phosphorous-containing lubricant additives is amine salt of phosphate ester > phosphoramide > phosphite ester > acid phosphate ester > phosphate ester > phosphonate ester > phosphinate ester.
- Sulfurized additives have a higher sulfur content with an excellent extreme pressure performance, and have a good compatibility with phosphorous-containing additives. Sulfur carrier has lower corrosion on metals, and it's suitable for formulating middle and high-grade vehicle gear oil and industrial gear oil.
It can be seen that the sulfur carrier lubricant additive has a higher extreme pressure bearing capacity under extreme conditions.
The application of sulfur-carrier additives in lubricant oil
At present, sulfurized olefins are the more widely used extreme pressure agent in lubricant oil, it has a good oil-solubility, good thermal stability, and are ideal EP additives, which are widely used in industrial gear oil, vehicle gear oil, metal working fluids, transmission oil, lubricant grease, and other lubricant oils that have a higher demand for extreme pressure.
For example, in the EP gear oil additive package, sulfurized lubricant additive (mainly sulfurized isobutylene) is over 50%.
Chorus can provide you with active sulfur-containing EP antiwear additive T321 (sulfurized isobutylene), with the features of high extreme pressure and strong oil solubility, which can satisfy the demands of gear oil and other industrial oils. Sulfurized additive T321 has low metal corrosion and excellent anti-wear performance.
Silfurized carrier EP antiwear additive, owing to its thermal stability, excellent solubility, light color, and low odor, has a strong compatibility and can improve the base oil's comprehensive lubricity under high temperature and heavy loading. Besides, sulfurized extreme pressure additives also have good anti-friction performance that can reduce wear and prolong the device's lifespan.
What's more, sulfur-containing additives are also widely used in metalworking fluids.
When processing difficult-to-machine materials like alloy steels, the built-up tends to form on the tool tip, influencing the cutting performance. Adding a sulfur-containing lubricant additive can overcome the drawback and improve the cutting efficiency.
Chorus is a professional lubricant supplier in China. We can provide you with high-performance sulfurized olefin extreme-pressure antiwear additive, and other various EP additives containing sulfur and phosphorous, such as antiwear EP additive thiophosphate chorus 211, antiwear EP additive triphenyl thiophosphate T309 TPPT.
Contact us and get more information and the latest price.
