Lubrication and Lubricants (2025)

A review: Oils, greases, lubricants, additives with superior properties

Journal of Research in Chemistry , 2025

The history of biodegradable lubricants has been presented in a series of articles, works and patents. A lubricating oil with good friction properties contains a lubricating oil and at least one additive, which has friction reducing properties, which is a block copolymer containing hydrophobic segments and polar segments. A complex composition of polymers used for the production of greases is reported by Lubrizol company researchers. Additives for lubricating oils with the ability to improve the viscosity index and shear stability were proposed by Mitsui. The creation of lubricating fluids with increased energy efficiency and high durability is the subject of a patent by the company Exxon Mobil.

Forming Usage Properties of Lubricants by the Functional Additives

Tribologia

The article presents the results of analysis of improvement possibilities of lubricating properties by the modification of lubricants with the use of functional additives that improve resistance to the wear and scuffing of frictional couple. The research encompasses different base oils. Mineral oil and the synthetic oils, i.e. ester oil and hydrocarbon oil, were investigated. Tribological investigations were conducted with the use of a four ball apparatus. The research results were analysed with particular consideration of simultaneous effects of two types of additives, i.e. anti-wear and anti-scuffing. As the result of research, the possibilities of forming a lubricant’s anti-wear and anti-scuffing properties have been demonstrated through the selection of the percentage of additives. The limitation of simultaneous improvement of both resistance to wear and scuffing was also demonstrated. This limitation is due to the additives’ interactions.

Reducing Wear and Friction by Means of Lubricants Mixtures

Procedia Engineering, 2013

In this study, two types of lubricants are mixed together in order to maximize wear reduction. Various compositions of mixtures are compared in terms of viscosity index, coefficient of friction and wear scar diameter. Heavy duty engine oil (HDEO) and automatic transmission fluid (ATF) have been used a lubricant condition. The standard procedures used in this study are ASTM D2270 for viscosity test method and ASTM D4172 for four balls tribology test method. Mixture of HDEO and ATF produces better friction resistance as compared to the original HDEO. The benefit of ATF can be used for engine lubrication.

Lubricants for Mechanical Equipments and Innovation in the Sector

2020

Lubricants are substances placed between two movable surfaces or a fixed and a movable one, forming a protective film whose main function is to reduce friction, wear, temperature and sealing of machine and motor components, and may also be a force transmission agent And movement. Therefore the objective of this work is to contribute to the construction of materials on the subject, aiming to analyze the types of lubricants, their characteristics, as well as the innovation in the sector. Thus, the applied methodology is mainly a literature review followed by an analysis. It should be noted that each type of lubricant is important for different types of equipment but is not yet in the state of the art and new technologies such as liquid crystal must be developed, which is highly efficient but still has a very high cost.

Influence of lubricant properties on elastohydrodynamic lubrication

Wear, 1999

In hard EHL, encountered in, e.g., gears, rolling element bearings etc. the properties of the lubricant play a significant role in the forming of a lubricating film and reducing friction between the contacting surfaces. The influence of pressure and temperature on viscosity, limiting shear stress and density, has to be taken into account when creating lubricant models to be used in numerical calculations of film thickness and friction. This paper describes some experimental methods to determine these properties of a number of different lubricating oils, both from mineral, vegetable and synthetic origin. The results show that, apart from 5P4E, naphthenic mineral oil has the highest values of pressure-viscosity as well as limiting shear stress-pressure coefficients. It also exhibits the highest density increase with pressure. Rapeseed oil has a rather high pressure-viscosity coefficient but a low limiting shear stress-pressure coefficient Ž . as well as a low density increase with pressure. Thus, rapeseed oil is a strong alternative to naphthenic and also paraffinic oil since it has the ability to form a relatively thick oil film and at the same time give a low coefficient of friction. Ester, polyglycol and polyalphaolefin oils also exhibit low values of friction but are not equally good as rapeseed oil to form a lubricant film as a result of their lower pressure-viscosity coefficients. q 1999 Elsevier Science S.A. All rights reserved.

Lubricating Aspects of Automotive Fuels

InTech eBooks, 2012

Lubricating oil

The use of natural gas as a vehicle fuel claimed to provide several benefits to engine components and effectively reduce maintenance requirements. It does not mix with or dilute the lubricating oil faster and will not cause deposits in combustion chambers as well as on spark plugs to the extent that the use of gasoline does, thereby generally extending the engine oil, piston ring and spark plug. This work compared the effect of both physical and chemical properties of motorcycle lubricating oil used by KRISS MODENAS 110cc motorcycle after running 5000 km using natural gas and gasoline respectively. The lubricating oil properties were tested according to standard ASTM methods. The results have shown that the lubricating oil where natural gas is used as the fuel suffers less property degradation as compared to the lubricating oil when gasoline was used as the fuel.

Wear in environmentally adapted lubricants with AW technology

Journal of Synthetic Lubrication, 2008

LUBRICITY OF LUBRICANTS

The aim of the experiment was determining the lubricity of different lubricants on water based drilling mud and to select the best lubricant to perform in different drilling activities. The lubricant reduces friction by producing a thin film of liquid that separates the solid surfaces in contact. Water-based mud is chosen as our base drilling fluid. This type of drilling fluid is the most common and one of the cheapest water-based drilling fluid systems. Moreover, this system is not strong enough to withstand and fight with high torque and its lubricity performance is insufficient. Therefore, the system was considered as our water based mud and different lubricants are added to determine the highest lubricant performances. From the experiment several lubricants were provided on which were to tested, by increase an of 1% by volume of each lubricant separately and was mixed into the drilling fluid on the stainless steel, then after wards the coefficient of friction for every lubricant was determined. The primary objective of experiment is to evaluate the performance of four lubricants. The lubricants were evaluated using a water-based drilling mud composed of lubricants with concentrations of 0%, 1%, 2%, 3%, 4% and 5% by volume. The experiment was carried out in a standard lubricity meter made by OFITE. The lubricity meter tests the ability of the lubricant in the drilling mud to reduce friction using parameters that imitate torque and drag produced by the fluid down hole. The formulations prepared were tested for torque reduction and all the lubricants studied lowered the coefficient of friction and showed significant torque reduction. The top performing lubricant among all three was LUB 3 which produced the highest torque reduction. Higher concentration of lubricant further lowered the coefficient of friction and improved lubricity. However, some of the lubricants showed little improvement in torque reduction and started leveling off beyond a concentration of 2%.

A CRITICAL REVIEW ON SOLID LUBRICANTS

The reduction of the interfacial friction between two surfaces in relative motion is a prerequisite for the proper functioning of many systems, ranging from machine parts to human joints. While the lubrication of two contacting surfaces primarily aims at the reduction of friction and wear, either by a separation of the surfaces by means of a fluid film or by introducing a layer of low shear strength between them, additional requirements such as the environmental compatibility of a lubricant or the energy efficiency of tribological systems have become important during recent years. This paper is limited to a discussion of the solid lubricants which comprise probably the largest single area. Although methods of attaching a lubricating solid to a wearing surface are many and vary considerably, the end result is the same, that is, a low friction medium is deposited to reduce friction and wear between two relatively moving surfaces under essentially dry conditions.