This is a widely used class of additives. Commonly used additives are divided into compounds containing S, P, Cl and other elements according to their composition; inorganic and organic solid lubricants such as various heavy metal chalcogenides; various metal fillers, etc. According to its mechanism of action, it can be divided into reactive type and layered crystal lubricating type. The reactive type also includes two types of additives that react with the metal surface to form a protective film and that the additive decomposes itself to form a protective film. Generally, reactive additives should be added after the grease is cooled, so as to avoid the decomposition and failure of the additives at high temperature, and also reduce the influence of the additives on the structure and properties of the grease. Most of the fillers are layered solid lubricants, such as graphite, MoS2, etc.

Anti-wear and extreme pressure additives can be divided into anti-wear agents, extreme pressure agents and anti-fretting wear agents according to their functions. Anti-wear agents mainly play the role of reducing friction and wear. Extreme pressure agent is mainly to prevent metal sintering or improve the bearing capacity of grease. The anti-fretting wear agent mainly inhibits oxidation, vibration wear and friction rust on the fretting wear surface. Generally, phosphorus compounds have anti-wear properties, while sulfur and chlorine compounds are ineffective in reducing wear, but are effective in improving extreme pressure and load resistance. Composite chlorine and phosphorus compounds or phosphorus and sulfur compounds have both anti-wear properties and Extreme pressure. In order to improve the antiwear extreme pressure property of the grease, two or more additives may be used in combination. However, it should be noted that polar compounds soften the grease and corrode copper.

According to the solubility in the base oil, extreme pressure antiwear agents are divided into oil-soluble and non-oil-soluble. Organic compounds containing sulfur, phosphorus, chlorine, molybdenum and other organic compounds are oil-soluble extreme pressure anti-wear additives, such as polysulfide isobutylene, zinc dialkyldithiophosphate, dialkyldithiocarbamate, dialkyldisulfide Molybdenum oxysulfide phosphoric acid ([(RO)2PS2]2MoOxSy), molybdenum oxysulfide dialkyl disulfide carbamate ([R2NCS2]2Mo2OxSy), etc.

A few non-oil-soluble anti-wear extreme pressure agents are organic solid lubricants, and most of them are inorganic solid lubricants, such as compound additives of polyaryl sulfide and dicalcium phosphate, Cu[(C6H11NO)n](OH)2, MCA ( melamine), MoS2, CeF3, SbSbS4, Cu, etc.

Dialkyldithiocarbamate is a dual-purpose additive, which has both anti-oxidation and anti-wear and extreme pressure properties. It is a general-purpose multi-effect additive. Such additives have been used successfully in many greases, engine oils and industrial lubricants. Its divalent and trivalent metal salts, such as zinc salts and cadmium salts, are mainly used as antioxidants, and also have anti-wear extreme pressure properties. Zinc salts can also function as metal passivators. Molybdenum, lead and antimony salts are mainly used as anti-wear extreme pressure agents and also as antioxidants. Trioctyl methyl thiomolybdate quaternary ammonium salt extreme pressure agent increases the Timken OK load (136-276kg) of polyurea grease, but it is ineffective when used in soap base grease. The reaction product of alkenyl succinic anhydride and ethanolamine can improve the fretting resistance of polyurea or lithium grease. In lithium-based grease, lanthanum oxide has good anti-wear extreme pressure, and has a good synergistic effect with molybdenum alkyl dithiocarbamate. The polycondensation product of fatty dibasic acid and fatty dihydric alcohol (relative molecular weight 500-5000) is an excellent anti-wear extreme pressure agent.

Borate or borate ester is a new type of anti-wear extreme pressure agent, by dispersing agent (such as anionic surfactant petroleum sulfonate), the very fine borate is dispersed in mineral oil, this dispersion system The borate is an amorphous sphere with an average diameter of 01 μm. It forms a microsphere film on the metal surface. The microsphere film has one to several layers, which can play a good lubricating effect and improve the anti-wear extreme pressure performance.