Extreme pressure composite lithium-based lubricating grease containing iron magnesium silicate micro-nano powder

Abstract

The invention relates to an extreme pressure composite lithium-based lubricating grease containing iron-magnesium silicate micro-nano powder, which comprises the following components in percentage by weight: 0.50-1.50% of a mixture of leaf serpentine and attapulgite or a mixture of leaf serpentine and sepiolite powder, and is characterized in that the mixing ratio of the two kinds of iron-magnesium silicate mineral powder is that the mixing ratio of the leaf serpentine powder to the attapulgite powder is 65.00-75.00%, and the mixing ratio of the attapulgite powder to the sepiolite powder is 25.00-35.00%. Or a mixture of 70.00%-80.00% of the serpentine powder and 20.00%-30.00% of the sepiolite powder, and in the chemical composition of the mixture, the content of MgO is greater than or equal to 38.00%, the content of FeO is 2.50%-4.00%, and the content of NiO is 0.50%-1.50%. The composite lithium-based lubricating grease has the beneficial effects that the produced composite lithium-based lubricating grease has the characteristics of extreme pressure resistance, friction reduction and wear resistance, can realize in-situ self-repairing of micro-wear of a friction pair, has good high-temperature resistance and oxidation resistance, is stable in quality, can further meet the lubrication requirements of equipment under severe conditions, and effectively prolongs the service life of friction parts.

Description

Technical Field

[0001] The invention belongs to the field of lubricating materials, and in particular relates to an extreme pressure composite lithium-based lubricating grease containing iron-magnesium silicate micro-nano powder. Background Art

[0002] Grease can adhere to the surface of the friction pair of mechanical equipment, reducing friction and wear. In order to improve the performance of grease, the existing technology usually adds various extreme pressure additives to improve the performance of the oil film on the friction surface, so as to achieve the purpose of anti-wear, friction reduction and long-term lubrication. However, when the operating conditions of mechanical equipment are harsh and complex, especially when the ambient temperature is high and the load is large, the extreme pressure lubrication film formed by the composite lithium-based grease with general extreme pressure additives is prone to failure. General extreme pressure additives cannot compensate for the surface wear of the friction pair and strengthen the surface through phase change and chemical reaction, and it is difficult to achieve the goal of significantly extending the service life of the friction parts of the equipment.

[0003] With the development of material technology, it has been proved that some natural iron magnesium silicate mineral powders with layered structures have the functions of reducing friction, resisting wear, and automatically repairing metal wear surfaces after entering the friction pair surface under the lubricant. Representative natural iron magnesium silicate minerals include antigorite, attapulgite and sepiolite. Antigorite is a polymorph of the serpentine family, presenting a monoclinic crystal state and a layered structure. The structural unit layer is composed of a hexagonal mesh of "magnesia" octahedral sheets and [SiO4] tetrahedral sheets in a ratio of 1:1. The theoretical composition (wB%) is: MgO 43.0, SiO2 44.1, H2O 12.9. Attapulgite and sepiolite are also monoclinic layered chain structures. Although the ideal crystal chemical formulas of the three layered structure minerals are different, they all contain different contents of MgO, SiO2, and H2O. The minerals all contain different contents of Fe, Ni, Cr, Mn, Al, F and other elements in the form of compounds and lattice isomorphisms. The active groups on the cross-section of antigorite, attapulgite and sepiolite mineral powders make them easily adsorbed on the surface of metal friction pairs. Under the shear force between the friction pairs, the layered structure produces interlayer sliding, thereby reducing friction resistance; at the same time, the microparticles provide good load support between the friction pairs, thereby playing a significant role in reducing friction resistance and extreme pressure resistance; the relative movement of the friction pairs causes instantaneous flash temperature in the wear protrusions, thereby causing the phase change of the iron magnesium silicate minerals. The -OH released by the phase change undergoes an esterification reaction with C and H in the oil to form a continuous polyester film, which can reduce both the friction coefficient and the surface wear of the friction pairs; during the phase change process, Fe 2+ With Mg 2+ Replacement occurs, forming a new surface layer of iron-magnesium silicate that compensates for wear; the Ni with catalytic properties released by the mineral phase change 2+Ions promote the formation of a new alloyed surface layer on the wear surface, increase the density and melting point of the new surface layer, and then form a new repair and strengthening layer with adaptive fit clearance, high hardness, super lubricity, high temperature resistance, and corrosion resistance. In this process, the structure, functional groups, magnesium, nickel, iron and other elements of ferromagnesium silicate minerals play an indispensable role. The use of antigorite, attapulgite and sepiolite mineral powders as grease additives can break through the limits of oil film lubrication, realize the combination of non-metallic materials and metal materials, and realize the transformation from friction-wear to lubrication-repair-strengthening, providing engineering possibilities for the preparation of composite lithium-based greases with extreme pressure resistance and self-repairing functions.

[0004] However, although the existing technology utilizes the structural characteristics of ferromagnesium silicate minerals and the properties of magnesium elements and functional groups, it ignores the differences in structure and composition between minerals and the necessity of ensuring the content of important elements such as iron and nickel involved in the repair and strengthening reaction. As a result, the quality of grease containing natural ferromagnesium silicate mineral additives is unstable, and the extreme pressure resistance and self-repair effects are not significant. Summary of the invention

[0005] The purpose of the present invention is to make up for the shortcomings of the prior art and provide a natural iron magnesium silicate mineral micro-nano powder, which can be used for a long time under harsh conditions, automatically repair the wear surface during the operation of mechanical parts and form a wear-resistant, super-lubricating, high-temperature-resistant, and corrosion-resistant complex phase repair and strengthening layer with adaptive fitting clearance, and an extreme pressure composite lithium-based grease with stable quality and extreme pressure and high temperature resistance.

[0006] The technical solution adopted by the present invention to solve the technical problem is an extreme pressure composite lithium-based grease containing iron magnesium silicate micro-nano powder, the components of which include, by weight percentage: a mixture of two kinds of iron magnesium silicate mineral antigorite and attapulgite powders or a mixture of two kinds of antigorite and sepiolite powders with a particle size of ≤5 microns 0.50% to 1.50%, dodecyl hydroxystearic acid 9.00% to 11.00%, sebacic acid 2.50% to 3.50% or azelaic acid 2.20% to 2.80% %, lithium hydroxide monohydrate 2.50% ~ 3.50%, polyisobutylene 1.80% ~ 2.20%, borate 1.20% ~ 1.80%, dialkyl dithiophosphate zinc 1.20% ~ 1.80%, diphenylamine 0.18% ~ 0.22% or diisooctyl diphenylamine 0.18% ~ 0.22%, thiobisphenol 0.18% ~ 0.22% or 2,6-di-tert-butyl-p-cresol 0.18% ~ 0.22%, the remainder is 100℃ kinematic viscosity 15.00mm 2 / s base oil; characterized in that the mixing ratio of the two iron-magnesium silicate mineral powders is a mixture of 65.00% to 75.00% antigorite powder and 25.00% to 35.00% attapulgite powder, or a mixture of 70.00% to 80.00% antigorite powder and 20.00% to 30.00% sepiolite powder, and the chemical composition of the mixture has a MgO content of ≥38.00%, a FeO content of 2.50% to 4.00%, and a NiO content of 0.50% to 1.50%.

[0007] The beneficial effects of the present invention are that the produced composite lithium-based grease has extreme pressure resistance, friction reduction, and anti-wear properties, can achieve in-situ self-repair of micro-wear of friction pairs, has good high temperature resistance and antioxidant capabilities, and has stable quality. It can further meet the lubrication requirements of equipment under harsh conditions and effectively extend the service life of friction parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The following is a detailed description of the embodiments with reference to the accompanying drawings.

[0009] Figure 1 This is a curve chart of the extreme pressure resistance test results of the product of Example 1; Figure 2 This is a curve chart of the extreme pressure resistance test results of the product of Example 2. Implementation Example

[0010] The components by weight percentage include: 100℃ kinematic viscosity 15.00mm 2 / s 500SN mineral base oil 77.60%, antigorite powder 0.70% and attapulgite powder 0.30% iron magnesium silicate mineral micro-nano powder mixture 1.00%, dodecyl hydroxystearic acid 10.00%, sebacic acid 3.00%, lithium hydroxide monohydrate 3.00%, polyisobutylene 2.00%, borate 1.50%, zinc dialkyl dithiophosphate 1.50%, diphenylamine 0.20%, and thiobisphenol 0.20%. The preparation method is as follows: (1) adding a magnesium iron silicate micro-nano powder blend, dodecyl hydroxystearic acid and sebacic acid to 50% base oil and heating to 80-90°C; (2) after the dodecyl hydroxystearic acid is melted, slowly adding lithium hydroxide monohydrate, heating to 135°C, controlling the heating rate at 0.4-0.5°C / min, saponification reaction time 2-3h, and depressurizing after saponification; (3) heating to 220°C, controlling the heating rate at 0.4-0.5°C / min, maintaining for 15 minutes, then adding the remaining base oil for rapid cooling, shear cooling to 120°C, adding polyisobutylene, borate, zinc dialkyl dithiophosphate, diphenylamine, and thiobisphenol, and then homogenizing at 25MPa, degassing under vacuum at -1.0MPa, and making a finished product. According to the current standard SH / T0202-1992 Lubricating Grease Extreme Pressure Performance Determination Method (Four-ball Machine Method), the extreme pressure resistance value P of the finished product is D 315kg, test results are attached Figure 1 . Example

[0011] The components by weight percentage include: 100℃ kinematic viscosity 15.00mm 2 / s 500SN mineral base oil 78.90%, antigorite powder 0.75% and sepiolite powder 0.25% composed of iron magnesium silicate mineral micro-nano powder mixture 1.00%, dodecyl hydroxystearic acid 10.00%, azelaic acid 2.50%, lithium hydroxide monohydrate 2.20%, polyisobutylene 2.00%, borate 1.50%, zinc dialkyl dithiophosphate 1.50%, diisooctyl diphenylamine 0.20%, 2,6-di-tert-butyl-p-cresol 0.20%. The preparation method comprises the following steps: (1) adding a magnesium iron silicate micro-nano powder blend, dodecyl hydroxystearic acid and azelaic acid to 40% base oil and heating to 80-90°C; (2) after the dodecyl hydroxystearic acid is melted, slowly adding lithium hydroxide monohydrate and water, heating to 145°C, controlling the heating rate at 0.4-0.5°C / min, maintaining constant temperature and pressure for 95-110 minutes, and then releasing the pressure for dehydration; (3) heating to 150°C and then adding 30% base oil, continuing to heat to 220°C and keeping the temperature for 15 minutes; (4) adding the remaining base oil, shear cooling to 120°C, adding polyisobutylene, borate, zinc dialkyl dithiophosphate, diisooctyl diphenylamine and 2,6-di-tert-butyl-p-cresol, homogenizing at 25MPa, and vacuum degassing at -1.0MPa to prepare the finished product. According to the current standard SH / T0202-1992 Lubricating Grease Extreme Pressure Performance Determination Method (Four-ball Machine Method), the extreme pressure resistance value P of the finished product is D 315kg, test results are attached Figure 2 .

Claims

1. An extreme pressure composite lithium-based grease containing iron magnesium silicate micro-nano powder, the components comprising by weight percentage: A mixture of two kinds of ferromagnesium silicate minerals, antigorite and attapulgite powders, or a mixture of two kinds of antigorite and sepiolite powders, with a particle size of ≤5 microns, 0.50% to 1.50%, dodecanedioic acid 9.00% to 11.00%, sebacic acid 2.50% to 3.50% or azelaic acid 2.20% to 2.80%, lithium hydroxide monohydrate 2.50% to 3.50%, polyisobutylene 1.80% to 2.20%, borate 1.20% to 1.80%, zinc dialkyl dithiophosphate 1.20% to 1.80%, diphenylamine 0.18% to 0.22% or diisooctyl diphenylamine 0.18% to 0.22%, thiobisphenol 0.18% to 0.22% or 2,6-di-tert-butyl-p-cresol 0.18% to 0.22%, the remainder is a kinematic viscosity of 15.00 mm at 100°C 2 / s base oil; characterized in that the mixing ratio of the two iron-magnesium silicate mineral powders is a mixture of 65.00% to 75.00% antigorite powder and 25.00% to 35.00% attapulgite powder, or a mixture of 70.00% to 80.00% antigorite powder and 20.00% to 30.00% sepiolite powder, and the chemical composition of the mixture has a MgO content of ≥38.00%, a FeO content of 2.50% to 4.00%, and a NiO content of 0.50% to 1.50%.

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