A composite solid lubricant for sprocket shaft assembly and a preparation method thereof

Abstract

The application belongs to the field of lubricants, and relates to a kind of chain wheel shaft group composite solid lubricant and its preparation method.The chain wheel shaft group composite solid lubricant is composed of the following raw materials by weight percentage: 2-15% of fluorinated graphite, 1-4% of terbium and thulium co-doped molybdenum disulfide, 1-3% of organic graphene, 0.07-0.4% of tin powder, 1-11% of polyethylene glycol, 1-7% of thickening agent, and the rest is base lubricating oil.The application co-dopes molybdenum disulfide with rare earth thulium and terbium, and thulium and terbium ions are embedded in the interlayer of molybdenum disulfide or replace molybdenum sites through electrostatic adsorption in the hydrothermal reaction process, so that the layered structure is more compact, and the oxidation and decomposition of molybdenum disulfide at high temperature are effectively inhibited, so that the lubricant has better oxidation resistance.The application introduces talc powder to modify lithium-based soap, and zinc ions are used to modify talc powder, so that the dispersibility of talc powder is improved, and the thermal stability, wear resistance and water resistance of the lubricant are improved after being compounded with lithium-based soap.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of lubricants, and particularly relates to a composite solid lubricant for a sprocket shaft set and a preparation method thereof. BACKGROUND

[0002] The sprocket shaft set is a core component in industrial transmission systems, which is composed of a sprocket, a shaft and bearings, etc. It is used for power transmission and chain engagement, and is commonly used in heavy equipment such as mine machinery and conveying equipment. Traditional lubricants for sprocket shaft sets are mostly lubricating oil or ordinary solid lubricants. Lubricating oil is prone to leakage under high load and strong vibration conditions, resulting in lubrication failure. The lubricating performance of ordinary solid lubricants is limited, and it is difficult to form a continuous and effective lubricating film on the complex friction pair surface of the sprocket shaft set, which cannot meet the requirements of long-term and high-strength work of the sprocket shaft set. At the same time, during the working process of the sprocket shaft set, the sprocket and the chain, the bearing and the shaft neck, etc. will produce intense friction and wear. The wear resistance of traditional lubricants is insufficient, and they cannot effectively reduce the friction coefficient and reduce wear. Under the dual action of high load and vibration, this wear condition will be more serious, resulting in serious wear of the parts of the sprocket shaft set and shortening the service life. Frequent replacement of the sprocket shaft set not only increases the maintenance cost of the equipment, but also causes the equipment to stop working, affecting the production efficiency of the coal mine. Moreover, the underground environment of the coal mine is humid and dusty, and the temperature changes greatly. The traditional lubricant is prone to metamorphism, hardening and other phenomena in such harsh environment, and loses its lubricating effect. In addition, the adaptability of traditional lubricants to different working conditions is poor, and they cannot maintain good performance under special working conditions such as high temperature, high load and low speed, especially in the case of strong vibration, their performance declines more obviously.

[0003] The existing common lubricants often only focus on the performance of one aspect, such as lubricity or wear resistance, while ignoring the comprehensive improvement of other performances. For example, some lubricants have good lubricating performance, but poor wear resistance; while other lubricants have poor oxidation resistance, thermal stability and short service life. Therefore, further research is still needed on the solid lubricant for the sprocket shaft set. SUMMARY

[0004] The first object of the present application is to provide a composite solid lubricant for a sprocket shaft set, which has excellent oxidation resistance, thermal stability and wear resistance.

[0005] The second object of the present application is to provide a preparation method of a composite solid lubricant for a sprocket shaft set, which has a simple process and is suitable for industrial production and popularization and application.

[0006] In order to achieve the above objects, the technical scheme adopted by the present application is as follows:

[0007] The application provides a kind of chain wheel shaft group with composite solid lubricant, which is composed of the following raw materials in percentage by weight: 2-15% of fluorinated graphite, 1-4% of terbium and thulium co-doped molybdenum disulfide, 1-3% of organic graphene, 0.07-0.4% of tin powder, 1-11% of polyethylene glycol, 1-7% of thickening agent, and the rest is base lubricating oil.

[0008] Further, the preparation method of the terbium and thulium co-doped molybdenum disulfide includes the following steps:

[0009] (1) Dissolve molybdenum pentachloride in a mixed solution of ethanol and deionized water to obtain solution A;

[0010] (2) Dissolve sodium sulfide, thulium chloride and terbium chloride in deionized water, then add solution A and sodium oleate, disperse uniformly, and then perform hydrothermal reaction. After the reaction, separate, wash and dry to obtain the product.

[0011] Further, in step (1), the amount ratio of molybdenum pentachloride, ethanol and deionized water is 0.1-0.2 mol: 1 L: 1 L.

[0012] Further, in step (2), the molar ratio of molybdenum pentachloride, thulium chloride, terbium chloride, sodium sulfide and sodium oleate is 1:(0.1-0.15):(0.1-0.15):(5-5.5):(4-8); the concentration of sodium sulfide dissolved in deionized water is 0.4-0.6 mol / L; the temperature of hydrothermal reaction is 180-220°C, and the time is 10-15 h.

[0013] Further, the thickening agent is talc powder modified lithium soap; the base lubricating oil is perfluoropolyether; and the organic graphene is ethylenediamine functionalized graphene oxide.

[0014] Further, the preparation method of the talc powder modified lithium soap includes the following steps:

[0015] (1) Add talc powder and sodium hydroxide to zinc chloride solution, and after reaction, filter, wash and dry to obtain modified talc powder;

[0016] (2) Mix the modified talc powder and 12-hydroxystearic acid by ball milling to obtain a modified talc powder-12-hydroxystearic acid composite;

[0017] (3) Add the modified talc powder-12-hydroxystearic acid composite to lithium hydroxide solution for saponification reaction, and then dehydrate to obtain the product.

[0018] Further, in step (1), the amount ratio of sodium hydroxide, talc powder and zinc chloride solution is 1 g: 3-5 g: 30-50 mL; the concentration of zinc chloride solution is 0.2-0.3 mol / L; and the reaction time is 0.5-1 h.

[0019] Further, in the step (2), the mass ratio of the modified talcum powder and 12-hydroxystearic acid is 1:3-7; the ball milling rotation speed is 500-600 r / min, and the ball milling time is 20-25 h.

[0020] Further, in the step (3), the mass ratio of the modified talcum powder-12-hydroxystearic acid compound and lithium hydroxide is 8-13:1-5; the mass concentration of the lithium hydroxide solution is 9-12%; the saponification reaction temperature is 85-100 DEG C, and the saponification reaction time is 10-20 h; and the dehydration temperature is 220-240 DEG C.

[0021] The application provides a preparation method of the chain wheel shaft set composite solid lubricant.

[0022] (1) According to the raw material composition, the terbium and thulium co-doped molybdenum disulfide, organic graphene, fluorinated graphite, tin powder, polyethylene glycol and thickening agent are uniformly mixed and ground to obtain a mixture;

[0023] (2) The mixture is heated to 150-160 DEG C, and then the base lubricating oil is added; the stirring speed is 500-1000 r / min, and the stirring time is 80-120 min; and then the mixture is cooled to room temperature.

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] In the raw material composition of the chain wheel shaft set composite solid lubricant, the terbium and thulium co-doped molybdenum disulfide and the talcum powder modified lithium soap are introduced, and the obtained chain wheel shaft set composite solid lubricant has excellent oxidation resistance, thermal stability and wear resistance.

[0026] (1) The rare earth thulium and terbium are used for co-doping molybdenum disulfide, wherein the rare earth ions are embedded between the molybdenum disulfide layers or replace the molybdenum sites through electrostatic adsorption in the hydrothermal reaction process, so that the edge sites of the molybdenum disulfide are reduced, and the layered structure is more dense; the structure strengthening can effectively inhibit the oxidation and decomposition of the molybdenum disulfide at high temperature. Furthermore, the rare earth has the oxygen affinity ability, and can form an oxide before molybdenum, which acts as a protective layer to prevent the oxidation of the molybdenum disulfide; and the terbium and thulium are variable valence rare earths, and the oxide layer can be self-repaired at high temperature. Therefore, compared with adding an antioxidant in the lubricant alone, the rare earth mixed doped molybdenum disulfide has better oxidation resistance.

[0027] (2) Lithium soap is a high-efficiency thickening agent commonly used in lubricants, which forms a three-dimensional network structure through the interweaving of soap fibers, and thickens the base oil into a stable paste-like grease. The synergistic effect of lithium soap and base oil can significantly reduce the direct contact of metal surfaces, reduce the friction coefficient, and form a more stable lubricating film when compounded with additives such as molybdenum disulfide, preventing metal surface scratches or adhesive wear. Lithium soap also has good water resistance and rust resistance, making it suitable for complex working conditions and providing sealing and shock absorption. However, the high-temperature stability of lithium soap is poor, so talc is introduced to modify lithium soap. Talc has a layered silicate structure, excellent lubricity and thermal stability, and a large number of hydrophilic hydroxyl groups on its surface. Under the action of alkaline conditions, it can coordinate or ion exchange with zinc ions, thereby expanding the interlayer spacing and increasing the porosity. The combination of talc and lithium soap can improve the thermal stability of the thickening agent, and improve the overall lubricity, wear resistance and water resistance of the lubricant. The increased porosity can also improve the dispersibility of talc and adsorb and release lubricants, maintaining the thermal stability of the lubricating network.

[0028] The preparation method of the composite solid lubricant for sprocket shaft set of the application has simple process, and is suitable for industrial production and popularization and application. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The scanning electron microscope image of the terbium and thulium co-doped molybdenum disulfide obtained in Example 1 of the application.

[0030] Figure 2 The scanning electron microscope image of the talc modified lithium soap obtained in Example 1 of the application. DETAILED DESCRIPTION

[0031] The following specific embodiments are used to further describe the technical solutions of the application. However, those skilled in the art should understand that the following examples are only used to illustrate the application, and should not be regarded as limiting the application. The specific conditions not mentioned in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, such as those not specifically mentioned, are conventional products obtained through market channels.

[0032] In the embodiments of the application, the organic graphene is ethylenediamine functionalized graphene oxide, and the preparation method is as follows: 0.1 g of graphene oxide is added to 100 mL of aqueous solution, and after ultrasonic treatment, a graphene oxide dispersion is obtained; 3 mL of graphene oxide dispersion is added to 100 mL of N,N-dimethylformamide, and after mixing and stirring for 30 min, ultrasonic treatment is carried out at 40℃ for 2 h to obtain a graphene oxide / dimethylformamide suspension; then 60 mL of ethylenediamine is added while stirring, and ultrasonic treatment is carried out at 30℃ for 2 h. After reaction, washing and drying, ethylenediamine functionalized graphene oxide is obtained.

[0033] Example 1

[0034] The embodiment provides a composite solid lubricant for a chain wheel shaft set, which is composed of the following raw materials in percentage by weight: 10% of fluorinated graphite, 3% of terbium and thulium co-doped molybdenum disulfide, 2% of organic graphene, 0.2% of tin powder, 6% of polyethylene glycol, 5% of a thickening agent (talcum powder modified lithium soap), and the rest of base lubricating oil (perfluoropolyether).

[0035] The preparation method of the terbium and thulium co-doped molybdenum disulfide in the embodiment comprises the following steps:

[0036] (1) Molybdenum pentachloride is dissolved in a mixed solution of ethanol and deionized water, and the amount ratio of molybdenum pentachloride, ethanol and deionized water is 0.15 mol: 1 L: 1 L, to obtain solution A;

[0037] (2) Sodium sulfide, thulium chloride and terbium chloride are dissolved in deionized water, and the concentration of sodium sulfide in the deionized water after dissolution is 0.5 mol / L; solution A and surfactant sodium oleate are then added and uniformly dispersed; the molar ratio of molybdenum pentachloride, thulium chloride, terbium chloride, sodium sulfide and sodium oleate is 1:0.12:0.12:5.3:6; heating is performed to 200 DEG C, and hydrothermal reaction is performed for 12 h; after reaction, separation, washing and drying are performed, to obtain terbium and thulium co-doped molybdenum disulfide.

[0038] The scanning electron microscope (SEM) image of the terbium and thulium co-doped molybdenum disulfide obtained in the embodiment is as shown in Figure 1 .

[0039] The preparation method of the talcum powder modified lithium soap in the embodiment comprises the following steps:

[0040] (1) Talcum powder and sodium hydroxide are added into 0.25 mol / L zinc chloride aqueous solution, and the amount ratio of sodium hydroxide, talcum powder and zinc chloride solution is 1 g:4 g:40 mL; ultrasonic stirring reaction is performed for 0.5 h; after filtration, washing and drying, modified talcum powder is obtained;

[0041] (2) The modified talcum powder and 12-hydroxystearic acid are mixed and ball milled at a mass ratio of 1:5, the ball milling speed is 550 r / min, and the ball milling time is 22 h, to obtain a modified talcum powder-12-hydroxystearic acid composite;

[0042] (3) The modified talcum powder-12-hydroxystearic acid composite is added into lithium hydroxide aqueous solution, and the mass ratio of the modified talcum powder-12-hydroxystearic acid composite and lithium hydroxide is 10:3; the mass concentration of lithium hydroxide in the lithium hydroxide aqueous solution is 10%; heating is performed to 90 DEG C, and saponification reaction is performed for 15 h under stirring; after reaction, dehydration is performed by heating to 230 DEG C, to obtain talcum powder modified lithium soap.

[0043] The scanning electron microscope (SEM) image of the talcum powder modified lithium soap obtained in the embodiment is as shown inFigure 2 As shown.

[0044] This embodiment provides a method for preparing a composite solid lubricant for sprocket shaft assemblies, including the following steps:

[0045] (1) According to the raw material composition, terbium-thulium co-doped molybdenum disulfide, organic graphene, fluorinated graphite, tin powder, polyethylene glycol and thickener are ground and mixed evenly, and the particle size after grinding is ≤80μm to obtain a mixture.

[0046] (2) Heat the mixture to 160°C, slowly add the base lubricating oil, stir at 800r / min for 100min, and then cool to room temperature to obtain the final product.

[0047] Example 2

[0048] This embodiment provides a composite solid lubricant for sprocket shaft assemblies, which is composed of the following raw materials by weight percentage: 15% fluorinated graphite, 1% terbium-thulium co-doped molybdenum disulfide, 1% organic graphene, 0.4% tin powder, 1% polyethylene glycol, 3% thickener (talc-modified lithium soap), and the balance being base lubricant (perfluoropolyether).

[0049] The method for preparing terbium-thulium co-doped molybdenum disulfide in this embodiment includes the following steps:

[0050] (1) Dissolve molybdenum pentachloride in a mixed solution of ethanol and deionized water, with a volume ratio of molybdenum pentachloride, ethanol and deionized water of 0.1 mol: 1 L: 1 L, to obtain solution A;

[0051] (2) Sodium sulfide, thulium chloride and terbium chloride were dissolved in deionized water. The concentration of sodium sulfide in the deionized water after dissolution was 0.4 mol / L. Solution A and surfactant sodium oleate were then added and dispersed evenly. The molar ratio of molybdenum pentachloride, thulium chloride, terbium chloride, sodium sulfide and sodium oleate was 1:0.1:0.1:5:4. The mixture was heated to 180°C and subjected to a hydrothermal reaction for 15 h. After the reaction, the mixture was separated, washed and dried to obtain terbium-thulium co-doped molybdenum disulfide.

[0052] The preparation method of talc-modified lithium soap in this embodiment includes the following steps:

[0053] (1) Add talc powder and sodium hydroxide to a 0.2 mol / L zinc chloride aqueous solution. The ratio of sodium hydroxide, talc powder and zinc chloride solution is 1 g: 3 g: 30 mL. Stir the mixture with ultrasonic stirring for 1 h, filter, wash and dry to obtain modified talc powder.

[0054] (2) The modified talc powder and 12-hydroxystearic acid were mixed at a mass ratio of 1:3 and ball-milled at a speed of 500 r / min for 25 h to obtain the modified talc powder-12-hydroxystearic acid composite.

[0055] (3) Add the modified talc-12-hydroxystearic acid complex to the lithium hydroxide aqueous solution. The mass ratio of the modified talc-12-hydroxystearic acid complex to lithium hydroxide is 13:1, and the mass concentration of lithium hydroxide in the lithium hydroxide aqueous solution is 9%. Heat to 85°C and stir for saponification reaction for 10 hours. After the reaction, raise the temperature to 220°C to dehydrate and obtain talc-modified lithium soap.

[0056] This embodiment provides a method for preparing a composite solid lubricant for sprocket shaft assemblies, including the following steps:

[0057] (1) According to the raw material composition, terbium-thulium co-doped molybdenum disulfide, organic graphene, fluorinated graphite, tin powder, polyethylene glycol and thickener are ground and mixed evenly, and the particle size after grinding is ≤80μm to obtain a mixture.

[0058] (2) Heat the mixture to 150°C, slowly add the base lubricating oil, stir at 600r / min for 120min, and then cool to room temperature to obtain the final product.

[0059] Example 3

[0060] This embodiment provides a composite solid lubricant for sprocket shaft assemblies, which is composed of the following raw materials by weight percentage: 8% fluorinated graphite, 4% terbium-thulium co-doped molybdenum disulfide, 3% organic graphene, 0.1% tin powder, 11% polyethylene glycol, 7% thickener (talc-modified lithium soap), and the balance being base lubricant (perfluoropolyether).

[0061] The method for preparing terbium-thulium co-doped molybdenum disulfide in this embodiment includes the following steps:

[0062] (1) Dissolve molybdenum pentachloride in a mixed solution of ethanol and deionized water, with a volume ratio of molybdenum pentachloride, ethanol and deionized water of 0.2 mol: 1 L: 1 L, to obtain solution A;

[0063] (2) Sodium sulfide, thulium chloride and terbium chloride were dissolved in deionized water, and the concentration of sodium sulfide in the deionized water after dissolution was 0.6 mol / L; then solution A and surfactant sodium oleate were added and dispersed evenly; wherein the molar ratio of molybdenum pentachloride, thulium chloride, terbium chloride, sodium sulfide and sodium oleate was 1:0.15:0.15:5.5:8; heated to 220℃ and carried out hydrothermal reaction for 10 h; after the reaction, the mixture was separated, washed and dried to obtain terbium-thulium co-doped molybdenum disulfide.

[0064] The preparation method of talc-modified lithium soap in this embodiment includes the following steps:

[0065] (1) Add talc powder and sodium hydroxide to a 0.3 mol / L zinc chloride aqueous solution. The ratio of sodium hydroxide, talc powder and zinc chloride solution is 1 g: 5 g: 50 mL. Stir the mixture with ultrasonic stirring for 1 h, filter, wash and dry to obtain modified talc powder.

[0066] (2) The modified talc powder and 12-hydroxystearic acid were mixed at a mass ratio of 1:7 and ball-milled at a speed of 600 r / min for 20 h to obtain the modified talc powder-12-hydroxystearic acid composite.

[0067] (3) Add the modified talc-12-hydroxystearic acid complex to the lithium hydroxide aqueous solution. The mass ratio of the modified talc-12-hydroxystearic acid complex to lithium hydroxide is 8:3, and the mass concentration of lithium hydroxide in the lithium hydroxide aqueous solution is 12%. Heat to 100°C and stir for saponification reaction for 20 hours. After the reaction, raise the temperature to 240°C to dehydrate and obtain talc-modified lithium soap.

[0068] This embodiment provides a method for preparing a composite solid lubricant for sprocket shaft assemblies, including the following steps:

[0069] (1) According to the raw material composition, terbium-thulium co-doped molybdenum disulfide, organic graphene, fluorinated graphite, tin powder, polyethylene glycol and thickener are ground and mixed evenly, and the particle size after grinding is ≤80μm to obtain a mixture.

[0070] (2) Heat the mixture to 160°C, slowly add the base lubricating oil, stir at 1000r / min for 80min, and then cool to room temperature to obtain the final product.

[0071] Comparative Example 1

[0072] The difference between this comparative example and Example 1 is that the terbium-thulium co-doped molybdenum disulfide is replaced with molybdenum disulfide.

[0073] Comparative Example 2

[0074] The difference between this comparative example and Example 1 is that thulium chloride was removed during the preparation process of terbium-thulium co-doped molybdenum disulfide.

[0075] Comparative Example 3

[0076] The difference between this comparative example and Example 1 is that steps (1) and (2) in the preparation method are omitted, and the modified talc-12-hydroxystearic acid complex in step (3) is replaced with 12-hydroxystearic acid.

[0077] Comparative Example 4

[0078] The difference between this comparative example and Example 1 is that the preparation step of modified talc in the preparation of talc-modified lithium soap is removed, that is, modified talc is replaced with talc.

[0079] Test case

[0080] The properties of the lubricants obtained in Examples 1-3 and Comparative Examples 1-4 were measured, and the results are shown in Table 1.

[0081] (1) The dropping point was determined according to GB / T 3498 "Determination of dropping point of grease over wide temperature range".

[0082] (2) The water loss (38℃, 1h) was determined according to SH / T 0109 "Determination of water resistance of lubricating grease".

[0083] (3) According to SH / T 0325 "Test Method for Oxidation Stability of Lubricating Grease", the lubricant was subjected to an oxidation experiment (100h) in an oxygen environment of 99℃ and 758kPa, and the degree of oxidation resistance was evaluated by the oxygen pressure reduction value (oxidation stability).

[0084] (4) According to SH / T 0189 "Determination of Anti-wear Performance of Lubricating Oil", a four-ball testing machine was used to evaluate the anti-wear performance by measuring the diameter of the steel ball wear scar under the test conditions of load: 392N, speed: 1200r / min, test time: 60min, and test temperature: 75℃.

[0085] Table 1

[0086]

[0087]

[0088] As shown in Table 1, the high-temperature resistance, oxidation resistance, wear resistance, and water resistance of Examples 1-3 of the present invention are all superior to those of Comparative Examples 1-4. Among them, Comparative Examples 1-2 show significantly worse oxidation resistance compared to Example 1. The reason for this is that the present invention utilizes rare earth thulium and terbium to co-dopat molybdenum disulfide. During the hydrothermal reaction, thulium and terbium ions are electrostatically adsorbed and embedded into the interlayer of molybdenum disulfide or replace molybdenum sites, making the layered structure denser and effectively inhibiting the oxidative decomposition of molybdenum disulfide at high temperatures, thus exhibiting better oxidation resistance. Comparative Examples 3-4 show significantly worse water resistance, thermal stability, and wear resistance compared to Example 1. The reason for this is that the present invention introduces talc powder to modify lithium-based soap and uses zinc ions to modify talc powder. Talc powder reacts with zinc ions under alkaline conditions, increasing the interlayer spacing and porosity, improving the dispersibility of talc powder, and thus, after being combined with lithium-based soap, improving the thermal stability and wear resistance of the lubricant, and enhancing the water resistance of the lubricant.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. Based on the present invention, some modifications or substitutions can be made, but these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of protection claimed by the present invention.

Claims

1. A composite solid lubricant for sprocket shaft assemblies, characterized in that, It is composed of the following raw materials by weight percentage: fluorinated graphite 2-15%, terbium-thulium co-doped molybdenum disulfide 1-4%, organic graphene 1-3%, tin powder 0.07-0.4%, polyethylene glycol 1-11%, thickener 1-7%, and the balance being base lubricating oil; The method for preparing terbium-thulium co-doped molybdenum disulfide includes the following steps: (1) Dissolve molybdenum pentachloride in a mixed solution of ethanol and deionized water to obtain solution A; (2) Dissolve sodium sulfide, thulium chloride and terbium chloride in deionized water, then add solution A and sodium oleate, disperse evenly and carry out hydrothermal reaction, then separate, wash and dry to obtain the product; The thickener is talc-modified lithium soap; the preparation method of the talc-modified lithium soap includes the following steps: (1) Add talc powder and sodium hydroxide to zinc chloride solution. After reaction, filter, wash and dry to obtain modified talc powder. (2) The modified talc and 12-hydroxystearic acid were mixed and ball-milled to obtain the modified talc-12-hydroxystearic acid complex; (3) Add the modified talc-12-hydroxystearic acid complex to lithium hydroxide solution for saponification reaction, and then dehydrate it to obtain the final product.

2. The composite solid lubricant for sprocket shaft assemblies as described in claim 1, characterized in that, In step (1) of the method for preparing terbium-thulium co-doped molybdenum disulfide, the ratio of molybdenum pentachloride, ethanol and deionized water is 0.1-0.2 mol: 1 L: 1 L.

3. The composite solid lubricant for sprocket shaft assemblies as described in claim 1, characterized in that, In step (2) of the method for preparing terbium-thulium co-doped molybdenum disulfide, the molar ratio of molybdenum pentachloride, thulium chloride, terbium chloride, sodium sulfide and sodium oleate is 1:(0.1-0.15):(0.1-0.15):(5-5.5):(4-8); the concentration of sodium sulfide dissolved in deionized water is 0.4-0.6 mol / L; the hydrothermal reaction temperature is 180-220℃ and the time is 10-15h.

4. The composite solid lubricant for sprocket shaft assemblies as described in claim 1, characterized in that, The base lubricant is perfluoropolyether.

5. The composite solid lubricant for sprocket shaft assemblies as described in claim 1, characterized in that, In step (1) of the method for preparing talc-modified lithium soap, the ratio of sodium hydroxide, talc, and zinc chloride solution is 1g:3-5g:30-50mL; the concentration of zinc chloride solution is 0.2-0.3mol / L; and the reaction time is 0.5-1h.

6. The composite solid lubricant for sprocket shaft assemblies as described in claim 1, characterized in that, In step (2) of the preparation method of the talc-modified lithium soap, the mass ratio of modified talc to 12-hydroxystearic acid is 1:(3-7); the ball milling speed is 500-600 r / min, and the ball milling time is 20-25 h.

7. The composite solid lubricant for sprocket shaft assemblies as described in claim 1, characterized in that, In step (3) of the method for preparing talc-modified lithium soap, the mass ratio of modified talc-12-hydroxystearic acid complex to lithium hydroxide is (8-13):(1-5); the mass concentration of lithium hydroxide solution is 9-12%; the saponification reaction temperature is 85-100℃ and the time is 10-20h; the dehydration temperature is 220-240℃.

8. The method for preparing the composite solid lubricant for sprocket shaft assemblies according to any one of claims 1-7, characterized in that, Includes the following steps: (1) According to the raw material composition, terbium-thulium co-doped molybdenum disulfide, organic graphene, fluorinated graphite, tin powder, polyethylene glycol and thickener are mixed evenly and ground to obtain a mixture. (2) Heat the mixture to 150-160℃, add the base lubricating oil, stir at 500-1000r / min for 80-120min, and then cool to room temperature to obtain the final product.

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