Lithium-based grease
author: Leila
2024-12-05
Lithium-based grease is made of natural fatty acid (stearic acid or 12-hydroxystearic acid) lithium soap, thickened with medium-viscosity mineral lubricant or synthetic lubricant, while synthetic lithium-based grease is made of synthetic fatty acid lithium soap, thickened with medium-viscosity mineral lubricant.
Characteristics of lithium-based grease
The characteristics of lithium-based grease are as follows:
(1) Lithium-based grease, especially grease thickened with 12-hydroxystearic acid lithium, has only two intersection temperatures. The first intersection temperature (i.e., from pseudo-gel state to gel state) is generally above 170°C, and the second phase transition temperature (i.e., from gel state to sol state) is generally above 200°C. Therefore, when suitable mineral oil is selected, it can be used for a long time at 120°C or for a short time at 150°C.
(2) Lithium-based grease, especially grease thickened with 12-hydroxystearic acid lithium, can be seen through electron microscopy that its soap fibers form double-stranded, entangled twisted ribbons, so it has good mechanical stability.
(3) The heat of adsorption of 12-hydroxystearate lithium and lithium stearate on alkanes was determined by gas chromatography. It was found that 12-hydroxystearate lithium and lithium stearate have greater bonding strength to the liquid phase on the soap fiber surface and to the liquid phase in the lattice. Therefore, lithium-based grease has better colloidal stability.
(4) The degree of solubility of alkali metals in water is relatively low. Therefore, lithium-based grease has better water resistance and can be used in mechanical parts that are wet and in contact with water.
(1) Lithium-based grease, especially grease thickened with 12-hydroxystearic acid lithium, has only two intersection temperatures. The first intersection temperature (i.e., from pseudo-gel state to gel state) is generally above 170°C, and the second phase transition temperature (i.e., from gel state to sol state) is generally above 200°C. Therefore, when suitable mineral oil is selected, it can be used for a long time at 120°C or for a short time at 150°C.
(2) Lithium-based grease, especially grease thickened with 12-hydroxystearic acid lithium, can be seen through electron microscopy that its soap fibers form double-stranded, entangled twisted ribbons, so it has good mechanical stability.
(3) The heat of adsorption of 12-hydroxystearate lithium and lithium stearate on alkanes was determined by gas chromatography. It was found that 12-hydroxystearate lithium and lithium stearate have greater bonding strength to the liquid phase on the soap fiber surface and to the liquid phase in the lattice. Therefore, lithium-based grease has better colloidal stability.
(4) The degree of solubility of alkali metals in water is relatively low. Therefore, lithium-based grease has better water resistance and can be used in mechanical parts that are wet and in contact with water.
Function of lithium-based grease
Lithium soap, especially 12-hydroxystearate lithium soap, has a strong ability to thicken mineral oil or synthetic oil. Therefore, compared with calcium-sodium-based grease, the thickening amount of lithium-based grease can be reduced by about 1/3, and the service life can be extended by more than double.
Lithium soap, especially 12-hydroxystearate lithium soap, has a strong ability to thicken mineral oil or synthetic oil. Therefore, compared with calcium-sodium-based grease, the thickening amount of lithium-based grease can be reduced by about 1/3, and the service life can be extended by more than double.
Lithium-based grease, especially grease thickened with 12-hydroxystearate lithium soap, becomes a multi-effect, long-life general-purpose grease after adding antioxidants, rust inhibitors and extreme pressure agents. It can replace calcium-based grease and sodium-based grease and is used for bearing lubrication of aircraft, automobiles, tanks, machine tools and various mechanical equipment.
General lithium-based grease (GB7324-1994): divided into 1#, 2# and 3# according to the consistency grade. It has good water resistance, mechanical stability, corrosion resistance and oxidation stability, and is suitable for the lubrication of rolling bearings and sliding bearings and other friction parts of various mechanical equipment within the working temperature of -20 to 120°C.
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