It is unnecessary to prove that additives for lubricating oils are used to improve tribological characteristics of lubricating oils and to impart to them some functions that the lubricating oils do not offer. When considered from the point of view of mechanisms of action, additives can be divided into those that perform surface chemical actions to achieve the intended aim and those that affect bulk characteristics of lubricating oils. The former include oiliness agents, detergents and dispersants, rust preventive agents, metal deactivators and so on and the latter include oxidation inhibitors, viscosity index improvers, agents reducing the flow point, and so on. When considering lubricants (lubricating oils and additives) from the aspect of surface chemistry, it becomes clear that the relation between surface chemistry and tribology is very close, for example, (1) Improvement of lubricity: adsorption, wetting, etc. (2) Cleaning of the lubrication system: cleaning of friction surface, purification of lubricants from degradation products, etc. (3) Manufacturing of lubricants: surface treatment and dispersion of solid lubricants, emulsification and solubilization of lubricating oils, etc. (4) Imparting lubricants functions that they do not possess: defoaming and foam suppression, rust prevention, corrosion prevention, etc. In this work, an improvement of lubricity of lubricating oils will be considered by focusing mainly on an improvement of friction and wear characteristics by the adsorption of oiliness agent of item (1) and other additives by friction surfaces. Other points will be considered in separate publications.
展开▼
