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7Li
Published in Guillaume Madelin, X-Nuclei Magnetic Resonance Imaging, 2022
Lithium is the lightest known metal and can be combined with aluminum, copper, manganese, and cadmium to make strong, lightweight metals. Lithium and its compounds have many industrial applications, such as heat-resistant glass and ceramics, lithium grease lubricants, flux additives for iron, steel and aluminum production, lithium batteries, and lithium-ion batteries (which use more than three quarters of lithium production). Lithium also has a low melting point and the highest heat capacity of any element, which can be applied as a coolant in some nuclear reactors. Lithium was important in early experiments in nuclear physics, where transmutation of lithium atoms to helium in 1932 was the first fully man-made nuclear reaction. Lithium deuteride (LiD) can serves as a fusion fuel in staged thermonuclear weapons. Lithium hydroxide (LiOH) is used to remove carbon dioxide from the atmosphere of spacecraft. Lithium stearate (LiC18H35O2) is used as a general purpose and high temperature lubricant. In medicine, lithium carbonate (Li2CO3) is generally used as a drug to treat depression disorders and gout.
Formulation and rheology of bio-grease mixed with h-BN nanoparticles
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Shariq Ahmad Bhat, M. S. Charoo
Sesame oil is used as base oil. India is the second-largest producer of sesame in the world and hence is chosen as lubricating oil. Lithiumstearate is used as a thickener. Lithium stearate greases have high oxidation stability and greater water resistance than other soap-based greases. Hexagonal boron nitride is used as an additive. It is a good antiwear additive and has proven very effective in improving the rheological properties of lubricants. The lubricity qualities of h-BN are excellent and there is weak bonding between the h-BN layers.The addition of nanoparticles to the grease can be done by two methods. In the first method, the nanoparticles are added to the base oil after which the grease is synthesized. In the second method, the grease is synthesized first and then the nanoparticles are added. A suitable solvent (chloroform) is added to the grease to dissolve it. The nanoparticles are then mixed and dispersed in the grease using a bath sonicator for about 3 hours. The composition is then kept in the furnace to remove the solvent and the nano grease is obtained. For better results,the first method is generally used as the nanoparticles get uniformly distributed throughout the grease microstructure. In the second method, the uniform distribution of nanoparticles is not so good as compared to the method first. For the synthesis of nano grease, nanoparticles in the following concentrations (1, 2, and 3 wt. %) are added to the base oil. The solution of base oil and nanoparticles is sonicated using a bath sonicator for about 4 hours. After sonication, the solution of base oil and nanoparticles is heated upto 80°C using a hot plate magnetic stirrer. Afterward, the thickener is added to the solution in small amounts.The mixture of sesame oil, additive, and thickener is heated to 180°C at which the base oil starts acquiring grease characteristics. The mixture is kept at this temperature for about 15 minutes and cooled slowly resulting in the development of nanogrease.