The magical effect of nano silica in lubricants!
October 02, 2021
The magical effect of nano silica in lubricants! In recent years, with the rapid development of nanotechnology, the excellent lubricating properties of nano-lubricating additives have attracted increasing attention. Nanomaterials can form a thin film with a low friction coefficient on the friction surface to fill and repair the friction surface to a certain extent. Nano-particles are small in size and can be considered as approximately spherical. They can roll freely like pebbles and act as a micro-bearing. They can also polish and strengthen the friction surface, support the load, and increase the load-bearing capacity and reduce the coefficient of friction. In addition, nano-particles have high diffusivity and self-diffusion ability, and it is easy to form a penetration layer or diffusion layer with excellent anti-wear performance on the metal surface, which shows the principle of in-situ tribochemistry. Therefore, the nano-lubricating additive has outstanding extreme pressure resistance, excellent anti-wear performance and better lubricating performance, and is suitable for working under heavy load, low speed and high temperature; at the same time, it is different from general solid lubricating materials. Adding a few nano additives to the grease can greatly improve the performance of the material. The amount of nanoparticles used in lubricating grease is very small. At the same time, the organic modifier molecules composed of c, H and O in the organic-inorganic composite nanoparticle additives have very little potential negative impact on the environment. Therefore, nanomaterials also have environmental advantages as lubricating additives friendly characteristics.
Nano-silica (VK-SP15, VK-SP30, VK-SP50), as a commonly used nano material, can be added to the Base Oil as a thickening agent. The grease prepared has a high drop point and a good high temperature I Energy; at the same time, it can also be added as an additive to grease to improve the extreme pressure and anti-wear properties of the product. It can be predicted that the application of nano-silica (VK-SP15, VK-SP30, VK-SP50) in lubricants will greatly improve the overall performance of lubricants. Nano SiO2 is used directly as a lubricating additive. Because nanomaterials have the characteristics of large specific surface area, high diffusivity, easy sintering, lower melting point, etc., using nanomaterials as additives can not only form an easy-to-shear film on the friction surface, reduce the friction coefficient, but also can carry out the friction surface A certain degree of filling and repairing, play an anti-wear effect.
Three types of nanoparticles, such as nano-SiO2, nano-LaF3 and nano-Ni, are added as additives to lithium-based grease. Through studying the effect on the friction and wear performance of steel-steel friction pairs, it is found that different nanoparticles have different mechanisms of action as grease additives. SiO2 and nano-LaF3 form a moderately thick and uniform boundary lubricant film on the wear surface of the steel ball to improve the tribological properties of the grease; while nano-Ni forms a relatively thick and uneven lubricating film on the wear surface of the steel ball , So its anti-friction and anti-wear effect is relatively poor. Silica particles (VK-SP30) with a size of about 40 nm were prepared by alkoxide hydrolysis precipitation method; the friction performance of nano-SiO2 (VK-SP30) as a Lubricant Additive was measured with a four-ball friction tester, and the wear scar was observed using SEM photos Surface morphology, the anti-wear mechanism of nano-SiO: was discussed. The research results show that because the surface of nano-SiO2 (VK-SP15, VK-SP30, VK-SP50) contains a large number of hydroxyl groups, an adsorption film can be formed between the friction pairs, thereby improving the wear resistance of the lubricating oil and protecting the solid surface The role of. Adding nano-SiO2 to the base oil can significantly improve its bearing capacity and anti-wear performance; at the same time, the addition amount of nano-SiO2 has an optimal value, and the anti-wear performance of the lubricating oil will decrease when the optimal value is exceeded. Adding silica with a particle size of less than 300nm to the lithium-based base grease, the test shows that the silica has good load-bearing capacity. Under the given test conditions, when the addition amount is 1.5%, the lithium-based base can be made The bearing capacity of grease is increased by more than 40%, and the sintering load is increased by more than 90%. In the friction process, the diameter of the long wear scar becomes smaller, and the abrasion resistance is improved. With the in-depth development of micro-tribology, thin-film lubrication theory, boundary lubrication theory, etc. in recent years, the application of nanoparticles as lubricating materials will inevitably be more extensive. Nano-lubricating additives prepared by chemical modification and other methods can effectively improve the tribological properties of lubricants. However, the size of nanoparticles is very small, and it is easy to form secondary particles. Therefore, through various surface modifications and surface treatments, improving the surface structure of nanoparticles, reducing the mutual attraction between particles, and avoiding the agglomeration of nanoparticles will become an important topic for future research and preparation of nano-lubricating materials. Since lubricating grease will inevitably cause certain pollution to the environment during use and post-treatment, the development of materials that are added in a small amount and are easily biodegradable is of great significance for reducing costs and reducing pollution. Therefore, it can be predicted that it has "self-repair" Functional and environmentally friendly lubricants will become the focus of future research and development.
