China 
Africa 
Explore chapters and articles related to this topic
Principles of Lubrication
Published in Heinz P. Bloch, Kenneth E. Bannister, Practical Lubrication for Industrial Facilities, 2020
Heinz P. Bloch, Kenneth E. Bannister
Though the retentive properties of grease—also resistance to heat, water, extreme loads, and other adverse conditions—depend primarily on the proportion and type of soap, frictional characteristics themselves are related almost entirely to the oil content. Base-oil viscosity is a determining factor in the ability of the grease to provide a proper lubricating film.
Lubricants and Lubrication
Published in Ahmed Abdelbary, Extreme Tribology, 2020
Basically, greases are composed of mineral (petroleum) and synthetic base oils (85–90% of the volume) thickened with metal soaps and other additives. Base fluids are usually categorized into two major categories, mineral (petroleum) oil or synthetic, each of which can be broken down into the following subcategories:
Lubrication and Wear
Published in Neville W. Sachs, Practical Plant Failure Analysis, 2019
An additive is a substance added to a base oil or a grease and most improve the performance characteristics of the lubricant but some, such as dyes and perfumes, are used to change the user’s perception of the lubricant. Figure 8.10 shows the formulation of a motor oil and all finished oils are combinations of a base oils and several additives. Greases are a combination of a base oil, additives, and a thickener. (In the section where we talked about the composition of steels we mentioned that making a steel alloy was a little like making a cake where certain ingredients are added to get a specific product. A similar approach holds true for making a lubricant.)
Thermodynamic Characterization of Grease Oxidation–Thermal Stability via Pressure Differential Scanning Calorimetry
Published in Tribology Transactions, 2022
Jude A. Osara, Piet M. Lugt, Michael D. Bryant, Michael M. Khonsari
Grease, a semipermanent semisolid lubricant, commonly lubricates bearings in machinery, vehicles, and other industrial equipment. Grease degrades mechanically, thermally, and chemically, eventually causing bearing failure if unchecked. Degradation is faster and more severe under certain high-load, high-temperature conditions. Oxidation and thermal stability of greases in bearing lubrication is crucial. Mechanical degradation from shear leads to a change in the grease microstructure that holds base oil. Mild shear only reorients the thickener material (usually fibers), whereas higher shear can break down the thickener. In most greases, this happens at relatively mild conditions due to molecules in the structure being physically (and not chemically) bonded. Chemical degradation requires more energy and in practice only occurs at high temperatures in the presence of oxygen. Usually, the grease base oil oxidizes, not the thickener.
An Evaporation Model for Base Oil from Grease-Lubricated Rolling Bearings including Breathing
Published in Tribology Transactions, 2021
Pramod Shetty, Robert Jan Meijer, Piet M. Lugt
Evaporation will take place from the surface of the grease itself. After all, grease consists mainly (80–90%) of base oil. In addition, it will occur from the very thin base oil layers that are formed on the functional surface of the bearing by grease bleed (33). The oil layers on the grooves and rolling elements are sheared/overrolled, so it may be assumed that the surfaces of these layers are regularly “refreshed.” Evaporated oil from these layers will be replenished with bled oil from the grease. The films are thin but sufficiently large (thickness on the order of magnitude 0.2 μm) to neglect the effect of disjoining pressure on the vapor pressure. Hence, it is assumed that the total surface area inside the bearing is covered with a layer of base oil or grease from where evaporation takes place. This surface area, denoted here by A, can be calculated by taking the sum of the surface areas of the inner ring, outer ring, shield, and rolling elements. The dimensions that are needed to calculate this for standard bearings can be found in rolling bearing catalogs such as SKF (34).
Treatment of wastewater containing oil and grease by biological method- a review
Published in Journal of Environmental Science and Health, Part A, 2021
P. Sanghamitra, Debabrata Mazumder, Somnath Mukherjee
Effective biodegradation of hydrocarbons by biological process directly depends on chemical structure and type of hydrocarbons, applied loading rate and type of bioreactor.[60] Oil is a fusion of hydrocarbons, which include benzene, toluene, ethylebenzene along with xylene (BTEX), polyaromatic hydrocarbons (PAHs), naphthalene, phenantherene, phenols and dibenzothiophene (NPD). All the hydrocarbons are not dissolved in water as oil and grease are generally hydrophobic in nature.[11] Greases are mixture of a thickener, a lubricating fluid and some additives to enhance performance. Lubricating oil is the most important component (around 95%) of oil and grease.[61] Triglycerides are present in animal fats and vegetable oils, which are esters of unsaturated and saturated monocarboxylic acids and trihydric alcohol glyceride. [62] The four major classes of hydrocarbons present in oil include aromatics (mono, di and polyaromatic hydrocarbons), saturated (cycloparaffins and alkanes), resins (contain polar molecules involving heteroatoms like S, N, O) and asphaltenes (molecules of polyaromatic with high molecular weight).[44]