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Lithium Soap
Lithium soap is a soap consisting of a lithium salt of a fatty acid. Sodium-based and potassium-based soaps are used as cleaning agents in domestic and industrial applications, whereas lithium soaps are used as components of lithium grease (white lithium). Lithium soaps are produced by saponification of triglycerides, using lithium hydroxide or lithium carbonate as the saponification agent. Lithium soaps are used as lubricant components and form-release agents at relatively high temperatures. The main components of lithium soaps are lithium stearate and lithium 12-hydroxystearate. Lithium grease Lubricating greases are commonly formulated as mixtures of an oil and a lithium soap thickener.Angelo Nora, Alfred Szczepanek, Gunther Koenen, "Metallic Soaps" in Ullmann’s Encyclopedia of Industrial Chemistry 2005 Wiley-VCH, Weinheim. Some formulations include PTFE or other substances, such as molybdenum disulfide. Lithium grease adheres particularly well to metal, is non-corro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lubricant
A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces. The property of reducing friction is known as lubricity. In addition to industrial applications, lubricants are used for many other purposes. Other uses include cooking (oils and fats in use in frying pans and baking to prevent food sticking), to reduce rusting and friction in machinery, through the use of motor oil and Grease (lubricant), grease, bioapplications on humans (e.g., lubricants for Replacement joint, artificial joints), ultrasound examination, medical examination, and sexual intercourse. It is mainly used to reduce friction and to contribute to a better, more efficient functioning of a mechanism. History Lubricants have been in some use for thousands of year ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dropping Point
The dropping point of a lubricating grease is an indication of the heat resistance of the grease and is the temperature at which it passes from a semi-solid to a liquid state under specific test conditions. It is dependent on the type of thickener used and the cohesiveness of the oil and thickener of a grease.Totten, G.E., ''Handbook of Lubrication and Tribology Volume 1: Application and Maintenance'', CRC Press, 2006, The dropping point indicates the upper temperature limit at which a grease retains its structure though is not necessarily the maximum temperature at which a grease can be used. Dropping point is used in combination with other testable properties to determine the suitability of greases for specific applications and for use in quality control. ASTM test procedure The dropping point test procedures are given in ASTM standards D-566 and D-2265. The test apparatus consists of a grease cup with a small hole in the bottom, test tube, two thermometers, a container, sti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constant-velocity Joint
A constant-velocity joint (also called a CV joint and homokinetic joint) is a mechanical coupling which allows the shafts to rotate freely (without an appreciable increase in friction or Backlash (engineering), backlash) and compensates for the angle between the two shafts, within a certain range, to maintain the same velocity. A common use of CV joints is in front-wheel drive vehicles, where they are used to transfer the engine's power to the wheels, even as the angle of the driveshaft varies due to the operation of the steering and Car suspension, suspension. History The predecessor to the constant-velocity joint was the universal joint (also called a ''Cardan joint'') which was invented by Gerolamo Cardano in the 16th century. A short-coming of the universal joint is that the rotational speed of the output shaft fluctuates despite the rotational speed of the input shaft being constant. This fluctuation causes unwanted vibration in the system and increases as the angle betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dropping Point
The dropping point of a lubricating grease is an indication of the heat resistance of the grease and is the temperature at which it passes from a semi-solid to a liquid state under specific test conditions. It is dependent on the type of thickener used and the cohesiveness of the oil and thickener of a grease.Totten, G.E., ''Handbook of Lubrication and Tribology Volume 1: Application and Maintenance'', CRC Press, 2006, The dropping point indicates the upper temperature limit at which a grease retains its structure though is not necessarily the maximum temperature at which a grease can be used. Dropping point is used in combination with other testable properties to determine the suitability of greases for specific applications and for use in quality control. ASTM test procedure The dropping point test procedures are given in ASTM standards D-566 and D-2265. The test apparatus consists of a grease cup with a small hole in the bottom, test tube, two thermometers, a container, sti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corrosion
Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engineering is the field dedicated to controlling and preventing corrosion. In the most common use of the word, this means electrochemical oxidation of metal in reaction with an oxidant such as oxygen, hydrogen, or hydroxide. Rusting, the formation of red-orange iron oxides, is a well-known example of electrochemical corrosion. This type of corrosion typically produces oxides or salts of the original metal and results in a distinctive coloration. Corrosion can also occur in materials other than metals, such as ceramics or polymers, although in this context, the term "degradation" is more common. Corrosion degrades the useful properties of materials and structures including mechanical strength, appearance, and permeability to liquids and ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal
A metal () is a material that, when polished or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, electricity and thermal conductivity, heat relatively well. These properties are all associated with having electrons available at the Fermi level, as against nonmetallic materials which do not. Metals are typically ductile (can be drawn into a wire) and malleable (can be shaped via hammering or pressing). A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polythiazyl, polymeric sulfur nitride. The general science of metals is called metallurgy, a subtopic of materials science; aspects of the electronic and thermal properties are also within the scope of condensed matter physics and solid-state chemistry, it is a multidisciplinary topic. In colloquial use materials such as steel alloys are referred to as metals, while others such as polymers, wood or ceramics are nonmetallic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molybdenum Disulfide
Molybdenum disulfide (or moly) is an inorganic chemistry, inorganic compound composed of molybdenum and sulfur. Its chemical formula is . The compound is classified as a transition metal dichalcogenide. It is a silvery black solid that occurs as the mineral molybdenite, the principal ore for molybdenum.Sebenik, Roger F. ''et al''. (2005) "Molybdenum and Molybdenum Compounds", ''Ullmann's Encyclopedia of Chemical Technology''. Wiley-VCH, Weinheim. is relatively unreactive. It is unaffected by dilute acids and oxygen. In appearance and feel, molybdenum disulfide is similar to graphite. It is widely used as a dry lubricant because of its low friction and robustness. Bulk is a Diamagnetism, diamagnetic, indirect bandgap semiconductor similar to silicon, with a bandgap of 1.23 eV. Production is naturally found as either molybdenite, a crystalline mineral, or jordisite, a rare low temperature form of molybdenite. Molybdenite ore is processed by Froth flotation, flotation to give ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polytetrafluoroethylene
Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene, and has numerous applications because it is chemically inert. The commonly known brand name of PTFE-based composition is Teflon by Chemours, a corporate spin-off, spin-off from DuPont (1802–2017), DuPont, which originally invented the compound in 1938. Polytetrafluoroethylene is a fluorocarbon solid, as it is a high-molecular-weight polymer consisting wholly of carbon and fluorine. PTFE is hydrophobic: neither water nor water-containing substances Wetting, wet PTFE, as fluorocarbons exhibit only small London dispersion forces due to the low polarizability, electric polarizability of fluorine. PTFE has one of the lowest Friction#Coefficient of friction, coefficients of friction of any solid. Polytetrafluoroethylene is used as a non-stick coating for Cookware and bakeware, pans and other Cookware and bakeware, cookware. It is Chemically inert, non-reactive, partly because of the strength of car ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grease (lubricant)
Grease is a solid or semisolid lubricant formed as a dispersion of thickening agents in a liquid lubricant. Grease generally consists of a soap emulsified with mineral or vegetable oil. A common feature of greases is that they possess high initial viscosities, which upon the application of shear, drop to give the effect of an oil-lubricated bearing of approximately the same viscosity as the base oil used in the grease. This change in viscosity is called shear thinning. Grease is sometimes used to describe lubricating materials that are simply soft solids or high viscosity liquids, but these materials do not exhibit the shear-thinning properties characteristic of the classical grease. For example, petroleum jellies such as Vaseline are not generally classified as greases. Greases are applied to mechanisms that can be lubricated only infrequently and where a lubricating oil would not stay in position. They also act as sealants to prevent the ingress of water and incompressible ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
