This paper introduces the role of lubricant additives, the application significance of dialkyl phosphite in it, focuses on its role as an anti-wear agent and extreme pressure agent, and its advantages in different application scenarios.
Its anti-wear mechanism can be explained by the following aspects:
1.Chemical polishing: The older view is that phosphorus-containing compounds form ferric phosphide compounds with iron under high temperature and pressure, and flow to the pits, preventing wear and tear on the surface of the machine. This effect is known as "chemical polishing".
2.Anti-wear effect of organic film: Under boundary lubrication conditions, phosphide can be adsorbed on the surface of the machine, and then the C-O bond will be broken, and it will react with the iron atoms on the surface of the machine to form an organic film. This organic film can form a uniform protective film on the surface of the machine, which plays a role in preventing the wear and tear of the machine surface.
3.Extreme pressure: Under high pressure conditions, the organoferric phosphate film containing phosphorus extreme pressure agent further reacts to form an inorganic iron phosphate reaction film to form a hard surface protective film, so that it can withstand high load without plastic deformation, thus playing the role of extreme pressure. The inorganic iron phosphate reaction film not only prevents the wear of the machine surface, but also reduces the friction coefficient of the machine surface and improves the operation efficiency of the machine.
Dialkyl phosphite esters can be divided into compounds with different carbon chain lengths, such as dibutyl phosphite (C4), didecyl phosphite (C10), and octadecene phosphite (C18), which also differ in their application in lubricants.
Dibutyl phosphite: The alkyl phosphite ester of C4 has high solubility and has a strong anti-wear agent and extreme pressure agent, but the high temperature resistance is poor, which has an impact on the stability.
Didecyl phosphite: The dialkyl phosphite ester of C10 has high stability, can maintain stability over a wide temperature range, and has good extreme pressure performance and lubricating properties.
Octacylenyl phosphite: C18's dialkyl phosphite combines excellent extreme pressure performance with excellent lubricating properties, especially at high temperatures or under heavy loads.
Dialkyl phosphite esters with different carbon chain lengths also have different odors. Dibutyl phosphite with short carbon chains usually has a pungent odor, while di-octadecenyl phosphite with long carbon chains has a lighter odor and is suitable for some application scenarios with high odor requirements.
There are also different application differences for dialkyl phosphite esters with different carbon chain lengths
Dibutyl phosphite is generally suitable for applications with light loads and lower temperatures, such as small engines or low-speed gears, and has good anti-wear and extreme pressure effects.
Didecyl phosphite is more suitable for medium and heavy duty applications, such as automotive drive shafts and industrial gear units, where it provides excellent lubrication and extreme pressure protection.
Di-octadecenyl phosphite is ideal for high temperature and heavy loads, such as large machinery in the steel and mining sectors, where it provides excellent lubrication and resistance to high temperatures.
Compounds with different carbon chain lengths of dialkyl phosphite also have different extreme pressure properties. Dialkyl phosphite with short and medium carbon chains perform well under extreme pressure conditions, but may be stable and prone to migration and decomposition at high temperatures.
Dialkyl phosphite with different carbon chain lengths are suitable for different types of lubricants, and the right application area can be selected according to their characteristics.
Dibutyl phosphite is mainly used in lubricants in light-duty machinery and at low temperatures, such as small engine oils, cutting oils and greases.
Didecyl phosphite is commonly used in medium and heavy-duty machinery and in a wide range of lubricant applications such as automotive engine oils, gear oils, hydraulic fluids, and greases.
Dioctadecenyl phosphite is mainly used in lubricants for high-temperature and heavy-duty machinery, such as industrial gear oils, hydraulic systems, and high-temperature greases.
Different types of dialkyl phosphite esters can be selected according to their performance characteristics to meet the needs of lubricants under different working conditions.
The characteristics and application differences of different carbon chain lengths of dialkyl phosphite esters are summarized. Short-chain dibutyl phosphite is suitable for light load and low temperature environments, and has good anti-wear and extreme pressure properties. Medium-chain didecyl phosphite is suitable for medium to heavy duty and a wide range of lubricant applications. Long-chain octadecenyl phosphite esters are suitable for high temperature and heavy load conditions, providing good lubricating properties and high temperature resistance. Depending on the desired oil and working conditions, the appropriate dialkyl phosphite ester is selected to improve the performance and effectiveness of the lubricant.