# An Analysis of the Process of Applying Technical Lubricating Coatings
###### Abstract
Among lubricants, we can distinguish: mineral oils, synthetic oils, vegetable oils, plastic lubricants, solid lubricants, adhesive agents, emulsions, and special lubricants. Mineral and synthetic oils can be refined or unrefined. Solid lubricants include powders, pastes, or lacquers [20]. Adhesive agents include bituminous lubricants. The used emulsions are those with an oil-in-water or water-in-oil structure. Water, acids, or gases are classified as special lubricants [21]. The composition of plastic lubricants, specifically the proportions and type of ingredients used, has a significant impact on their properties. Even small changes in this area can result in significant modifications. The base oil (main component), which constitutes between 70% and 90% of the product, greatly influences the tribological properties of the lubricants [22,23]. Studies have shown the importance of the type of base oil used. Among the analyzed lubricants, the best performance was found with a plant-based dispersing base, which showed high efficiency in terms of protection against friction and wear. Mineral oil does not guarantee adequate anti-seize protection, despite guaranteeing anti-wear protection. Synthetic oils showed very low anti-friction properties and were twice as weak in anti-wear properties compared to mineral or plant-based oils. The important parameters that determine the tribological properties of the resulting compositions are the viscosity of the dispersion phase and the reaction occurring between the friction surface and the plastic lubricant, which precisely determines the significant impact of the products of this reaction [22]. The structure of plastic grease is determined by the type of thickener and its particle size. To increase the ability to rebuild the grease structure, a polymer additive (e.g., PTFE) should be added for mineral greases. Talc performs the same function in synthetic-based greases [24; 25]. The functional additives of lubricants ensure their operational durability. It has been found that the most optimal anti-wear conditions are guaranteed by the simultaneous use of greases with a polymer additive and fullerene nanostructures of carbon. This conclusion was drawn on the basis of a comparison with grease with one additive [24]. Temperature can be an intensifying factor for the action of additives, which directly affects node protection [26; 27]. Most lubricants produced have durability at a temperature of 80 \({}^{\circ}\)C. They are able to work in these temperature conditions for even several thousand hours. If the temperature at which they are used increases, their structure often degrades and they lose their properties. For example, one of the basic ingredients of such a lubricant may undergo oxidation, which reduces its durability to only a few hours at a temperature of 150 \({}^{\circ}\)C. It is a fact that the durability of a lubricant is inversely proportional to the temperature at which it is used--the higher it is, the more its durability significantly decreases. In addition, an increase in the temperature of the lubricant may be caused by bearing load. The result of an increased load is a higher temperature and a reduction in the rotational speed of the bearing. In such a situation, choosing lubricants of a different consistency class or with improved parameters is the solution [28]. It is not advisable to use plastic lubricants at low temperatures; however, some situations require the use of lubricants with increased resistance to negative temperatures. This occurs, for example, in aviation, where the plastic lubricants used have a durability at a temperature of \(-\)54 \({}^{\circ}\)C. Their use is safe due to the low-temperature melting synthetic base fluid [29]. Consistency is a parameter that informs us about the stiffness of the lubricant. In engineering solutions, it can be stated that the lubricant has been correctly selected for a specific application if, during the operation of the bearing or other element, it does not expose adjacent parts to increased friction [28].