Types and Main Functions of Lubricating Oil Additives (III)

Additives are the essence of modern high-grade lubricants. Proper selection of reasonable additions can improve their physical and chemical properties, impart new special properties to lubricants, or enhance their original properties to meet higher requirements.According to the quality and performance of the lubricant requirements, careful selection of additives, careful balance, and reasonable deployment are the key to ensuring the quality of the lubricant. As introduced before, the commonly used additives are: viscosity index improver, pour point depressant, antioxidant, detergent dispersant, friction moderator, oil agent, extreme pressure additive, Anti-foaming agent, metal passivator, emulsifier, anti-corrosion agent, anti-rust agent, demulsifier, anti-oxidant anti-corrosion agent, etc.

In addition, we will talk about the solid additives commonly used in the market. There are many additives in the market that claim to improve the oil protection function, and different brands use different mechanisms of action to promote.

The following is a brief description of several types: (1) Graphite and molybdenum disulfide solid suspension type  It is Mainly used for antifriction and antiwear, but can only be applied to solid lubrication and low speed and high load equipment, they have no effect when the number of engine revolutions exceeds 1000 r/min. In addition, its state in the lubricating oil is unstable, and precipitation occurs under a certain time and temperature conditions. The precipitates cause blockage of the oil passage and accelerate the formation of sludge. (2) Teflon resin particle type As an anti-wear agent, it has been widely used in the United States, but it will be blocked on the oil passage and oil pump filter at low temperature, and it will be deactivated in the piston ring groove and accelerate the formation of sludge, this type is rarely recommended in the United States. (3) Coatings containing heavy metal particles such as copper and lead A metal film can be formed on the friction surface to prevent abrasion and extreme pressure, but an oil filter with a slightly larger filter element diameter must be used, otherwise it will be filtered out to block the oil pump and oil circuit. In addition, the use of it for a long time will form a film on the surface of the piston and the cylinder body, causing the two to bond, and the phenomenon of sticking loops is likely to occur. (4) Magnetic oils  It is a surface metal magnetizer, mainly used for anti-friction and anti-wear. The effective time of such products is too short, need to be added continuously, the cost is high, and it will interfere with the normal operation of the electronic components on the car. (5) Chlorine type “Chlorine” is a good extreme pressure agent, but it is not suitable for the high temperature and high speed working environment of the engine, and it will produce acid under suitable conditions, posing a potential danger to the metal in the engine. In addition, chlorine additives may be associated with existing additives in the lubricant, causing other side effects. (6) Lead-free, fluorine-free, chlorine-free chemical film formers It can simultaneously exhibit extreme pressure resistance, oxidation resistance and certain anti-wear properties. Because of its long-lasting chemical reaction film formed on the metal surface, it can effectively extend the life of lubricating oil and metal parts.