Ionic compound serving as gelator and lubricant additive, preparation method of ionic compound and application of ionic compound in conductive lubricant

Abstract

The invention relates to the technical field of lubricating materials, and provides an ionic compound serving as a gelator and a lubricating oil additive, a preparation method of the ionic compound and application of the ionic compound in a conductive lubricant. The ionic compound provided by the invention can be applied as a gelator or a lubricating oil additive; when being used as a gelator, the polymer can be self-assembled into lubricating oil with a complex three-dimensional network structure and capturing liquid in base oil, a solid-like conductive gel lubricant is formed, and the conductive gel lubricant has excellent thermal and mechanical responsiveness, good friction performance and excellent conductive performance; under the action of various electric fields, the lubricating oil shows excellent friction reduction and wear resistance, and electric corrosion on the surface of a friction pair can be effectively reduced. Besides, the ionic compound can also be used as a lubricating oil additive, can improve the antifriction, antiwear and extreme pressure properties and the like of the lubricating oil, also endows the lubricating oil with a conductive property, and can still show excellent lubricating property under the clamping of an electric field.

Description

Technical Field

[0001] This invention relates to the field of lubricating materials technology, and in particular to an ionic compound used as a gelling agent and lubricating oil additive, its preparation method, and its application in conductive lubricants. Background Technology

[0002] Conductive lubricants are a class of special functional materials that possess both lubrication and friction reduction as well as conductivity and energy dissipation. The importance and necessity of their research are fundamentally determined by the core requirements of modern industry for "high-efficiency transmission + low-loss operation and maintenance," especially in fields such as electronics, new energy, and high-end equipment, where their role has evolved from "auxiliary material" to "critical performance assurance material." Their performance directly determines the signal stability of electronic devices, the safe lifespan of new energy vehicles, and the extreme environmental adaptability of aerospace equipment, making them key materials supporting the development of high-end manufacturing. In traditional materials, conductivity and lubrication are inherently contradictory—conductive materials (such as metal powders and carbon-based materials) are mostly hard particles, easily exacerbating friction and wear; lubricating materials (such as mineral oil and fluorinated oil) are mostly insulating media, blocking current transmission. In modern industry, many critical components require simultaneous "stable current transmission" and "wear control." Without suitable conductive lubricants, equipment failure will be directly caused. Therefore, it is necessary to research new lubricating materials, adjusting the interfacial interaction between conductive materials and the matrix through molecular design to achieve a synergistic improvement in conductivity and lubrication performance, obtaining novel conductive lubricating materials that integrate conductivity and lubrication.

[0003] In recent years, supramolecular gel lubricants have gained widespread attention due to their unique structure and designability. These materials possess a unique three-dimensional network structure that can trap flowing lubricating oil, forming a solid-like gel-like material, thus solving the problem of lubricating oil creeping and migration. Furthermore, these materials exhibit excellent thermal and mechanical responsiveness; the reversible transition from gel to sol state can be achieved through thermal or mechanical manipulation, ensuring that the supramolecular gel lubricant performs excellent lubrication and sealing functions during friction. More importantly, these materials have high designability; through precise design of gel factors, various factors such as friction reduction, wear resistance, oxidation resistance, and high-temperature resistance can be introduced, resulting in a series of new supramolecular gel lubricants suitable for different working conditions, such as high-temperature resistant, oxidation-resistant, and high-vacuum resistant supramolecular gel lubricants.

[0004] However, most of the current gelling agents are non-ionic. These gelling agents assemble into a three-dimensional network structure through non-covalent bonding. They do not have ion conduction capabilities, and the supramolecular gel matrix they construct does not have electrical conductivity, thus failing to meet the requirements of conductive lubricants. Summary of the Invention

[0005] In view of this, the present invention provides an ionic compound as a gelling agent and lubricating oil additive, a method for its preparation, and its application in conductive lubricants. Through precise design, the present invention obtains an ionic compound that can be used as a gelling agent or lubricating oil additive, and develops a new class of supramolecular gel lubricating materials with conductive properties.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: An ionic compound having the structure shown in Formula I: Formula I; In Formula I: R is an alkyl chain with a chain length of 12 to 18, and X is O or S.

[0007] Preferably, the alkyl chain has a chain length of 12, 16, or 18.

[0008] The present invention also provides a method for preparing the ionic compound described above, comprising the following steps: (1) The compound with the structure shown in Formula A, an organic solvent and N,N-dimethylethylenediamine are mixed and reacted to obtain an intermediate; the structure of the intermediate is shown in Formula B. RN=C=X Equation A; Formula B; In equations A and B, X is O or S; (2) The intermediate, di(2-ethylhexyl) phosphate and organic solvent are mixed and reacted to obtain an ionic compound with the structure shown in Formula I.

[0009] Preferably, the molar ratio of the compound with the structure shown in Formula A to N,N-dimethylethylenediamine is 1:1 to 1.5; the reaction temperature in step (1) is 20 to 25°C and the time is 3 to 10 hours.

[0010] Preferably, the molar ratio of the intermediate to di(2-ethylhexyl) phosphate is 1:1 to 1.5; the reaction temperature in step (2) is 40 to 80°C and the reaction time is 10 to 15 h.

[0011] The present invention also provides the application of the ionic compound described above in conductive lubricants, wherein when the length of the alkyl chain is 12 to 17, the ionic compound is used as a lubricating oil additive; and when the length of the alkyl chain is 18, the ionic compound is used as a gelling agent.

[0012] The present invention also provides an ionic conductive gel lubricant, comprising a base oil and an ionic gelling agent, wherein the ionic gelling agent is an ionic compound as described above, and the alkyl chain in Formula I has a chain length of 18.

[0013] Preferably, the mass fraction of the ionic gel factor in the ionic gel lubricant is 10-14%.

[0014] The present invention also provides an ionic conductive lubricating oil, comprising a base oil and a lubricating oil additive, wherein the lubricating oil additive is an ionic compound as described in the above scheme, and the alkyl chain in Formula I has a chain length of 12 to 17.

[0015] Preferably, the mass fraction of the lubricating oil additive in the ionic conductive lubricating oil is 3-10%.

[0016] This invention provides an ionic compound having the structure shown in Formula I. The ionic compound provided by this invention includes a phosphate anion and a urea functional group, and its molecular structure is confirmed by proton nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. In this invention, when the alkyl chain length in the ionic compound is 12-17, it can be used as a lubricating oil additive; when the alkyl chain length is 18, it can be used as an ionic gelling agent. Specifically, when the ionic compound of this invention is used as a lubricating oil additive, it can improve the friction-reducing and anti-wear properties of the lubricating oil and reduce energy consumption. As a gelling agent, it can self-assemble into a complex three-dimensional network structure in the base oil, capturing liquid lubricating oil and forming a solid-like conductive gel lubricant, thereby preventing lubricating oil creep and migration, improving the friction-reducing and anti-wear properties of the lubricating oil, and reducing economic losses. Simultaneously, the formed gel lubricant transforms from a gel state to a sol state during use to reduce viscous resistance, thereby reducing energy loss. More importantly, the ionic compound provided by this invention can impart good electrical conductivity to the lubricant, meeting the requirements of a conductive lubricant.

[0017] This invention also provides an ionic conductive gel lubricant, comprising a base oil and an ionic gelling agent, wherein the ionic gelling agent is an ionic compound as described above, and the alkyl chain length in Formula I is 18. The ionic conductive gel lubricant provided by this invention exhibits excellent thermal and mechanical responsiveness, achieving a reversible transition from the gel to sol state under force or heat. Simultaneously, the gel lubricant provided by this invention demonstrates excellent friction reduction and anti-wear properties under no electric field conditions. More importantly, the design of the ionic gelling agent endows the gel lubricant with conductive properties, exhibiting excellent friction reduction and anti-wear properties under various electric fields, effectively reducing electrolytic corrosion on the friction pair surface. This novel conductive gel lubricant material is of great significance for the development of high-reliability and long-life components under electric field service conditions.

[0018] This invention also provides an ionic conductive lubricating oil, comprising a base oil and a lubricating oil additive, wherein the lubricating oil additive is an ionic compound as described above, and the alkyl chain length in Formula I is 12-17. The ionic conductive lubricating oil provided by this invention exhibits excellent frictional and current-carrying frictional properties. Detailed Implementation

[0019] This invention provides an ionic compound having the structure shown in Formula I: Formula I; In Formula I: R is an alkyl chain with a chain length of 12 to 18, and X is O or S.

[0020] In this invention, the chain length of the alkyl chain can be 12, 16 or 18; the alkyl chain is specifically a straight-chain alkyl chain.

[0021] In this invention, the ionic compound can specifically be any one of the following structures: Formula I-1; Formula I-2; Formula I-3.

[0022] The ionic compound provided by this invention can completely dissolve in base oil under stirring conditions, and after stabilization, forms an ionic conductive gel lubricant or an ionic conductive lubricating oil. When used as a gelling agent, this ionic compound can gel various alkane lubricating oils, resulting in a gel lubricant with excellent electrical conductivity and improved friction reduction and anti-wear properties of the lubricating material.

[0023] The present invention also provides a method for preparing the ionic compound described above, comprising the following steps: (1) The compound with the structure shown in Formula A, an organic solvent and N,N-dimethylethylenediamine are mixed and reacted to obtain an intermediate; the structure of the intermediate is shown in Formula B. RN=C=X Equation A; Formula B; In equations A and B, X is O or S; (2) The intermediate, di(2-ethylhexyl) phosphate and organic solvent are mixed and reacted to obtain an ionic compound with the structure shown in Formula I.

[0024] In this invention, a compound with the structure shown in Formula A, an organic solvent, and N,N-dimethylethylenediamine are reacted to obtain an intermediate; the structure of the intermediate is shown in Formula B. In this invention, the structural formula of N,N-dimethylethylenediamine is shown in Formula C; when X is O or S, the compound with the structure shown in Formula A is specifically a compound with the structure shown in Formula A-1 or Formula A-2, and the structure of the intermediate is specifically Formula B-1 or Formula B-2; Formula C; RN=C=O (Formula A-1); RN=C=S (Formula A-2); Formula B-1; Formula B-2.

[0025] In this invention, the compound with the structure shown in Formula A is an alkyl isocyanate or an alkyl isothiocyanate, specifically a dodecyl isocyanate, a hexadecyl isocyanate, or an octadecyl isocyanate; the alkyl isothiocyanate is a dodecyl isothiocyanate, a hexadecyl isothiocyanate, or an octadecyl isothiocyanate; the molar ratio of the compound with the structure shown in Formula A to N,N-dimethylethylenediamine is preferably 1:1 to 1.5, more preferably 1:1; the organic solvent is preferably a haloalkane, more preferably dichloromethane; the ratio of the amount of the compound with the structure shown in Formula A to the amount of organic solvent is preferably 0.01 mol: 100 mL.

[0026] In this invention, the reaction temperature in step (1) is preferably 20-25°C, and the reaction time is preferably 3-10 h, specifically 6 h, starting from the time N,N-dimethylethylenediamine is added completely; the reaction is preferably carried out under nitrogen protection; in a specific embodiment of this invention, the compound with the structure shown in formula A is preferably dissolved in an organic solvent, and then N,N-dimethylethylenediamine is added dropwise, and the reaction is carried out at a constant temperature after the addition is complete. After the reaction is completed, the precipitate is preferably separated, washed, and dried to obtain an intermediate; the washing agent is preferably dichloromethane, and the drying is preferably vacuum drying, with the vacuum drying time preferably being 12 h.

[0027] After obtaining the intermediate, the present invention mixes the intermediate, di(2-ethylhexyl) phosphate, and an organic solvent to react and obtain an ionic compound with the structure shown in Formula I. In the present invention, the molar ratio of the intermediate to di(2-ethylhexyl) phosphate is preferably 1:1 to 1.5, more preferably 1:1; the organic solvent is preferably tetrahydrofuran; the molar ratio of the intermediate to the organic solvent is preferably 0.005 mol: 50 mL; the reaction temperature in step (2) is preferably 40 to 80 °C, specifically 60 °C, and the reaction time is preferably 10 to 15 h, specifically 12 h; the reaction is preferably carried out under nitrogen protection. After the reaction is completed, the present invention preferably evaporates the organic solvent in the reaction system and dries the remaining product to obtain an ionic compound with the structure shown in Formula I; the drying is preferably vacuum drying, the vacuum drying temperature is preferably 40 °C, and the drying time is preferably 12 h.

[0028] The present invention also provides the application of the ionic compound described above in lubricating oil. When the length of the alkyl chain is 12 to 17, preferably 12 or 16, the ionic compound is used as a lubricating oil additive; when the length of the alkyl chain is 18, the ionic compound is used as an ionic gelling agent.

[0029] The present invention also provides an ionic conductive gel lubricant, comprising a base oil and an ionic gel factor, wherein the ionic gel factor is an ionic compound as described above, and the alkyl chain in Formula I has a chain length of 18; the mass fraction of the ionic gel factor in the ionic conductive gel lubricant is 10-14%, specifically 10%, 11%, 12% or 13%.

[0030] In this invention, the base oil is preferably a polyalphaolefin, specifically one or more of PAO2, PAO4, PAO10, PAO40 and 500N, more preferably PAO2.

[0031] In this invention, the preferred method for preparing the ionic gel lubricant includes: dissolving the ionic gel factor in base oil by stirring and allowing it to stand to obtain the ionic gel lubricant; during the standing process, the ionic gel factor undergoes self-assembly, and the lubricant changes from transparent to milky white until it is completely solidified.

[0032] The present invention also provides an ionic conductive lubricating oil, comprising a base oil and a lubricating oil additive, wherein the lubricating oil additive is an ionic compound as described above, wherein the alkyl chain length in Formula I is 12 to 17, specifically 12 or 16; the mass fraction of the lubricating oil additive in the ionic conductive lubricating oil is preferably 3 to 10%.

[0033] In this invention, the type of base oil is the same as in the above scheme, and will not be repeated here.

[0034] In this invention, the method for preparing the lubricating oil composition preferably includes: dissolving the lubricating oil additive in a base oil by stirring to obtain the lubricating oil composition.

[0035] The performance of the ionic conductive gel lubricant and the ionic conductive lubricating oil was tested in this embodiment of the invention: Thermogravimetric analysis (TGA) results show that the ionic conductive gel lubricant has high thermal stability, and differential scanning calorimetry (DSC) results show that the ionic conductive gel lubricant has a low phase transition temperature.

[0036] The ionic conductive gel lubricant provided by this invention exhibits good mechanical stability. Rheological data show that the ionic conductive gel lubricant possesses certain shear resistance, as well as good creep recovery and shear thinning properties.

[0037] The ionic conductive gel lubricant and ionic conductive lubricating oil provided by this invention have excellent tribological properties. The lubrication performance of the gel lubricant and lubricating oil was tested using an SRV-V fretting friction and wear tester. The test results show that the addition of ionic additives greatly improves the friction-reducing and anti-wear properties, as well as the load-bearing capacity of the lubricant.

[0038] The ionic conductive gel lubricant and ionic conductive lubricating oil provided by this invention exhibit excellent current-carrying tribological properties. The current-carrying lubrication performance of these gel lubricants and lubricating oils was tested using an Anton Paar TRB3 friction testing machine connected to an external digital CC&DC power supply. The test results show that the addition of ionic additives effectively improves the friction-reducing and anti-wear performance of the lubricant under current-carrying conditions.

[0039] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0040] In the following examples, the intermediates were prepared as follows: 0.01 mol of isocyanates of different alkyl groups (12, 16, 18) were dissolved in 100 mL of dichloromethane in a three-necked flask under nitrogen protection. Under magnetic stirring, 0.01 mol (0.88 g) of N,N-dimethylethylenediamine was added dropwise to the system through a constant-pressure dropping funnel. After the addition was complete, the mixture was stirred continuously for 6 hours, and a white precipitate formed. The precipitate was separated and washed three times with dichloromethane, then dried under vacuum for 12 hours to obtain the white solid product DN, which was designated DN12, DN16, and DN18 according to the length of the alkyl chain.

[0041] Example 1 The structural formula of NP18 gel factor is: A milky white semi-solid product was obtained in 95.7% yield. FTIR (KBr, cm⁻¹) -1 ): 3340.58,2922.05,2852.68,1654.86,1562.28,1467.77, 1176.53, 1047.31. In a nitrogen atmosphere, 0.005 mol (1.9 g) of intermediate DN18, 0.005 mol (1.61 g) of bis(2-ethylhexyl) phosphate, and 50 mL of tetrahydrofuran solvent were added to a round-bottom flask, and the mixture was stirred at 60 °C for 12 hours. After the reaction was complete, the tetrahydrofuran was separated using a rotary evaporator, and the remaining product was dried in a vacuum oven at 40 °C for 12 hours to obtain the milky white semi-solid final product NP18 gel factor.

[0042] Example 2 The structural formula of NP16 lubricant additive is: A pale yellow semi-solid product was obtained in 94.2% yield. FTIR (KBr, cm⁻¹) -1 ): 3339.42,2921.45,2852.98,1654.88,1562.48,1467.47, 1176.58, 1047.71. In a nitrogen atmosphere, 0.005 mol (1.77 g) of intermediate DN16, 0.005 mol (1.61 g) of bis(2-ethylhexyl) phosphate, and 50 mL of tetrahydrofuran solvent were added to a round-bottom flask and reacted at 60 °C with stirring for 12 hours. After the reaction was complete, the tetrahydrofuran was separated using a rotary evaporator, and the remaining product was dried in a vacuum oven at 40 °C for 12 hours to obtain the pale yellow semi-solid final product NP16 lubricating additive.

[0043] Example 3 The structural formula of NP12 lubricant additive is: A milky white semi-solid product was obtained in 94.7% yield. FTIR (KBr, cm⁻¹) -1 ): 3339.42,2920.31,2852.77,1655.12,1562.24,1467.31, 1176.31, 1047.63. In a nitrogen atmosphere, 0.005 mol (1.5 g) of intermediate DN12, 0.005 mol (1.61 g) of bis(2-ethylhexyl) phosphate, and 50 mL of tetrahydrofuran solvent were added to a round-bottom flask and reacted at 60 °C with stirring for 12 hours. After the reaction was complete, the tetrahydrofuran was separated using a rotary evaporator, and the remaining product was dried in a vacuum oven at 40 °C for 12 hours to obtain the pale yellow liquid final product NP12 lubricating additive.

[0044] Example 4 Preparation of ionic conductive gel lubricants: 0.1 g of NP18 and 0.9 g of PAO 2 were placed in a 5 mL glass bottle and stirred vigorously at room temperature until the gelling agent was completely dissolved. After standing for a period of time, the lubricant changed from transparent to milky white until it completely solidified, yielding an ionic conductive gel lubricant with an NP18 mass fraction of 10%. The same method was used to prepare 13% ionic conductive gel lubricants with NP18 mass fractions of 11% and 12%, respectively denoted as 10%NP18, 11%NP18, 12%NP18, and 13%NP18.

[0045] Example 5 Preparation of ionic conductive lubricating oil: 0.03 g of NP12 or NP16 and 0.97 g of PAO 2 were placed in a 5 mL glass bottle and stirred vigorously at room temperature until the gelling agent was completely dissolved, respectively, to obtain 3% NP12 and NP16 ionic conductive lubricating oils by mass fraction, which were denoted as 3%NP12 and 3%NP16, respectively.

[0046] Example 6 The thermal stability and phase transition temperature of the ionic conductive gel lubricant were obtained using TGA and DSC testing techniques, and the results are shown in Table 1.

[0047] Table 1. Phase transition temperature and thermal decomposition temperature of ionic conductive gel lubricants

[0048] The data in Table 1 clearly show that the phase transition temperatures of the ionic conductive gel lubricants are all around 26℃. The thermal decomposition temperatures of the different conductive gel lubricants all exceed 240℃, indicating that these conductive gel lubricants possess good thermal stability.

[0049] Example 7 The rheological properties of ionic conductive gel lubricants were tested using an Anton Paar MCR 302 rheometer. A PP 25 rotor with a 1 mm gap was used. The yield stress and elastic modulus of the conductive gel lubricant were measured in oscillation mode, and the creep recovery properties were measured in rotation mode. Specific test conditions are as follows: (a) Variable shear stress: Temperature: 10 ℃, Frequency: 1 Hz, Shear stress: 0.001~100 Pa; (b) Variable frequency: Temperature: 10 ℃, Frequency: 0.01~100 Hz, Shear stress: 5 Pa; (c) Creep recovery performance: Low shear rate: 0.5 s -1 High shear rate: 200 s -1 The experimental results are shown in Table 2, taking gel lubricants of different concentrations (10~13%) as examples.

[0050] Table 2 Rheological data of ionic conductive gel lubricants

[0051] Table 2 shows that this ionic conductive gel lubricant has a certain ability to resist external pressure, and its yield stress and elastic modulus increase with the increase of gel factor content. Furthermore, under repeated alternating shearing, the gel can recover its original viscosity, indicating that this ionic conductive gel lubricant has excellent creep recovery performance.

[0052] Example 8 The tribological properties of the ionic conductive gel lubricant prepared in Example 4 were evaluated using an SRV-V micro-vibration tribological testing machine. The upper sample for the steel / steel friction pair was a Φ10 mm AISI 52100 steel ball, and the lower sample was a Φ24 mm, 8 mm thick AISI 52100 steel block with a hardness of 700-750 HV. A three-dimensional profile measuring instrument was used to quantitatively analyze the wear volume after testing.

[0053] The specific test conditions are as follows: (a) Constant load: Load: 200 N, Temperature: 25 ℃, Frequency: 25 Hz, Amplitude: 1 mm, Test time: 30 min; (b) Variable load: Load: 50-1000 N, Rate: 2 min / 50 N, Temperature: 25 ℃, Frequency: 25 Hz, Amplitude: 1 mm; (c) Variable temperature: Load: 200 N, Temperature: 25-200 ℃, Rate: 3 min / 25 ℃, Frequency: 25 Hz, Amplitude: 1 mm; (d) Variable frequency: Load: 200 N, Temperature: 25 ℃, Frequency: 15-80 Hz, Rate: 2 min / 5 Hz, Amplitude: 1 mm. Taking ionic gel lubricants with a concentration of 10-14 wt% as an example, PAO2 was selected as a control. The test results are shown in Tables 3-6.

[0054] Table 3 shows the average coefficient of friction and average wear volume of PAO2 and ionic conductive gel lubricant under a 200 N load. It is clear from Table 3 that the coefficient of friction and wear volume of PAO2 are much greater than those of the ionic conductive gel lubricant, indicating that the ionic conductive gel lubricant has better friction reduction and anti-wear properties. Tables 4-6 show the average coefficients of friction of PAO2 and ionic conductive gel lubricant under different loads, temperatures, and frequencies. Tables 4-6 show that conductive gel lubricants can improve the load-bearing capacity and high-temperature resistance of lubricating oil, and maintain a stable coefficient of friction under high-frequency conditions. The above data demonstrate that ionic conductive gel lubricants have good extreme pressure and high-temperature resistance lubrication properties.

[0055] Table 3. Average coefficient of friction and friction volume of conductive gel lubricant at 200 N.

[0056] Table 4. Average coefficient of friction of ionic gel lubricant under variable load conditions

[0057] Table 5 Average coefficient of friction of ionic gel lubricants under varying temperature conditions

[0058] Table 6 Average coefficient of friction of ionic gel lubricant under variable frequency conditions

[0059] Example 9 The tribological properties of the ionic conductive lubricating oil prepared in Example 5 were evaluated using an SRV-V micro-vibration tribological testing machine. The upper sample of the steel / steel friction pair was a Φ10 mm AISI 52100 steel ball, and the lower sample was a Φ24 mm, 8 mm thick AISI 52100 steel block with a hardness of 700-750 HV. A three-dimensional profile measuring instrument was used to quantitatively analyze the wear volume after testing.

[0060] The specific test conditions are as follows: (a) Constant load: Load: 200 N, Temperature: 25 ℃, Frequency: 25 Hz, Amplitude: 1 mm, Test time: 30 min; (b) Variable load: Load: 50-1000 N, Rate: 2 min / 50 N, Temperature: 25 ℃, Frequency: 25 Hz, Amplitude: 1 mm; PAO2 was selected as the control test. The test results are shown in Tables 7 and 8.

[0061] Table 7 shows the average coefficient of friction and average wear volume of PAO2 and ionic conductive lubricating oil under a 200 N load. It is evident from Table 7 that, compared to PAO2, the wear volume and coefficient of friction of the ionic conductive lubricating oil are significantly reduced, indicating that this lubricating oil has excellent friction-reducing and anti-wear properties. Table 8 shows the average coefficient of friction of PAO2 and ionic conductive lubricating oil under different loads. Compared to the base oil, the ionic conductive lubricating oil has enhanced load-bearing capacity. The above data demonstrate that this ionic conductive lubricating oil possesses excellent tribological properties.

[0062] Table 7. Average coefficient of friction and friction volume of ionic conductive lubricating oil at 200 N.

[0063] Table 8 Average coefficient of friction of ionic conductive lubricating oil under variable load conditions

[0064] Example 10 The lubrication performance of the ionic conductive gel lubricant prepared in Example 4 was tested under current carrying conditions of 3 A and 6 A using an Anton Paar TRB3 friction testing machine with an external digital CC&DC power supply. The upper sample of the steel / steel friction pair was a Φ6 mm steel ball, and the lower sample was a Φ24 mm steel block with a thickness of 8 mm. The wear volume after testing was measured using a three-dimensional profile measuring instrument. The test results are shown in Tables 9 and 10.

[0065] Table 9 shows the average coefficient of friction and average wear volume of PAO2 and ionic conductive gel lubricant under conditions of 10 N and 3 A. Table 10 shows the average coefficient of friction and average wear volume of PAO2 and ionic conductive gel lubricant under conditions of 10 N and 6 A. The results show that the coefficient of friction and wear volume of PAO2 are much larger than those of the other two lubricating materials. Increasing the current leads to an increase in the coefficient of friction and wear volume of PAO2, while the coefficient of friction and wear volume of ionic conductive gel lubricant remain stable. This indicates that ionic conductive gel lubricant has superior lubrication performance under current-carrying conditions.

[0066] Table 9. Average coefficient of friction and friction volume of ionic conductive gel lubricants at 10 N and 3 A.

[0067] Table 10. Average coefficient of friction and frictional volume of ionic conductive gel lubricants at 10 N and 6 A.

[0068] Example 11 The lubrication performance of the ionic conductive lubricating oil prepared in Example 5 was tested under current carrying conditions of 3 A and 6 A using an Anton Paar TRB3 friction testing machine with an external digital CC&DC power supply. The upper sample of the steel / steel friction pair was a Φ6 mm steel ball, and the lower sample was a Φ24 mm steel block with a thickness of 8 mm. The wear volume after testing was measured using a three-dimensional profile measuring instrument. The test results are shown in Tables 11 and 12.

[0069] Table 11 shows the average coefficient of friction and average wear volume of the ionic conductive lubricating oil under conditions of 10 N and 3 A. Table 12 shows the average coefficient of friction and average wear volume of the ionic conductive lubricating oil under conditions of 10 N and 6 A. The results show that the coefficient of friction and wear volume of PAO2 are much greater than those of the two lubricating materials. Increasing the current leads to an increase in the coefficient of friction and wear volume of PAO2, while the coefficient of friction and wear volume of the ionic conductive lubricating oil remain stable. This indicates that ionic compounds, as additives to conductive lubricating oils, have superior lubrication performance under current-carrying conditions.

[0070] Table 11 Average coefficient of friction and friction volume of ionic conductive lubricating oil under electric field conditions at 10 N and 3 A.

[0071] Table 12 Average coefficient of friction and friction volume of ionic conductive lubricating oil under electric field conditions at 10 N and 6 A

[0072] As can be seen from the above embodiments, the ionic conductive gel lubricant provided by the present invention has good thermodynamic and rheological properties, as well as excellent boundary lubrication and current-carrying tribological properties. The ionic conductive lubricant provided also has excellent friction and current-carrying friction properties.

[0073] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An ionic compound, characterized in that, It has the structure shown in Equation I: Equation I; In Formula I: R is an alkyl chain with a chain length of 12 to 18, and X is O or S.

2. The ionic compound according to claim 1, characterized in that, The alkyl chain has a chain length of 12, 16, or 18.

3. The method for preparing the ionic compound according to claim 1 or 2, characterized in that, Includes the following steps: (1) The compound with the structure shown in Formula A, an organic solvent and N,N-dimethylethylenediamine are mixed and reacted to obtain an intermediate; the structure of the intermediate is shown in Formula B. RN=C=X Equation A; Formula B; In equations A and B, X is O or S; (2) The intermediate, di(2-ethylhexyl) phosphate and organic solvent are mixed and reacted to obtain an ionic compound with the structure shown in Formula I.

4. The preparation method according to claim 3, characterized in that, The molar ratio of the compound with the structure shown in Formula A to N,N-dimethylethylenediamine is 1:1 to 1.5; the reaction temperature in step (1) is 20 to 25°C and the time is 3 to 10 hours.

5. The preparation method according to claim 3, characterized in that, The molar ratio of the intermediate to di(2-ethylhexyl) phosphate is 1:1 to 1.5; the reaction temperature in step (2) is 40 to 80°C and the reaction time is 10 to 15 h.

6. The application of the ionic compound according to claim 1 or 2 in conductive lubricants, characterized in that, When the length of the alkyl chain is 12-17, the ionic compound is used as a lubricating oil additive; when the length of the alkyl chain is 18, the ionic compound is used as a gelling agent.

7. An ionic conductive gel lubricant, characterized in that, It includes a base oil and an ionic gelling agent, wherein the ionic gelling agent is an ionic compound as described in claim 1 or 2, and the alkyl chain in formula I has a chain length of 18.

8. The ionic conductive gel lubricant according to claim 7, characterized in that, The mass fraction of the ionic gel factor in the ionic gel lubricant is 10-14%.

9. An ionic conductive lubricating oil, characterized in that, It includes base oil and lubricating oil additives, wherein the lubricating oil additives are ionic compounds as described in claim 1 or 2, and the alkyl chain in formula I has a chain length of 12 to 17.

10. The ionic conductive lubricating oil according to claim 9, characterized in that, The mass fraction of lubricating oil additives in the ionic conductive lubricating oil is 3-10%.

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