Graphene-based lubricating oil additive as well as preparation method and application thereof

Abstract

The invention provides a graphene-based lubricating oil additive as well as a preparation method and application thereof, and belongs to the technical field of industrial pump lubrication. The graphene-based lubricating oil additive provided by the invention comprises the following components in percentage by mass: 0.6-5% of a hydroxylated graphene-nano tungsten disulfide composite material, and hydroxylated graphene and nano tungsten disulfide in the hydroxylated graphene-nano tungsten disulfide composite material form an interlayer intercalation structure; 2-8% of nano magnesium aluminum silicate; 0.3%-1.2% of porous silicon dioxide elastic particles; 1%-5% of fluorinated carbon nanotubes; 0.5-2% of a corrosion inhibitor; and the balance of base oil. The graphene-based lubricating oil additive provided by the invention is used for lubricating a water pump, has an excellent cavitation damage repairing effect, is excellent in wear resistance and friction reduction performance, is beneficial to reducing the load current of a motor and improving the energy efficiency, and also has an excellent noise reduction effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial pump lubrication, and particularly relates to a graphene-based lubricating oil additive and a preparation method and application thereof. BACKGROUND

[0002] A water pump is a machine for conveying liquid or increasing the pressure of liquid, which transmits mechanical energy or other external energy to liquid to increase the energy of liquid, and mainly conveys liquid such as water, oil, acid-base liquid, emulsion, suspension emulsion and liquid metal. In order to ensure the stable operation of the water pump, lubricating oil is usually used. The high-speed rotation of the impeller in the water pump will cause cavitation collapse impact (local pressure up to 1 GPa), that is, cavitation damage occurs, leading to pitting corrosion and micro-crack propagation on the metal surface. Moreover, the traditional water pump lubricating oil has a high friction coefficient (>0.1), large noise, large motor load current, accounts for 20-30% of the power consumption of the industrial system, and has low energy efficiency.

[0003] Since graphene has been discovered by the scientific community, it has been widely used as an anti-wear agent in lubricating oil additives due to its special structure and good mechanical properties. However, the use of graphene as a single anti-wear agent in traditional lubricating oil additives cannot solve the problems of cavitation damage repair of water pumps and low energy efficiency caused by high motor load current. SUMMARY

[0004] The present application provides a graphene-based lubricating oil additive and a preparation method and application thereof. The graphene-based lubricating oil additive provided by the present application is used for water pump lubrication, has excellent cavitation damage repair effect, excellent anti-wear and friction-reducing performance, is beneficial to reducing the motor load current and improving the energy efficiency, and also has excellent noise reduction effect.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0006] The present application provides a graphene-based lubricating oil additive, which comprises the following components in mass percentage:

[0007] 0.6-5% of a hydroxylated graphene-nano tungsten disulfide composite material, wherein the hydroxylated graphene and the nano tungsten disulfide in the hydroxylated graphene-nano tungsten disulfide composite material form an interlayer insertion structure;

[0008] 2-8% of nano magnesium aluminum silicate;

[0009] 0.3-1.2% of porous silica elastic microparticles;

[0010] 1-5% of carbon fluoride nanotubes;

[0011] 0.5-2% of an corrosion inhibitor;

[0012] The balance is base oil.

[0013] Preferably, the mass ratio of hydroxylated graphene to nano-tungsten disulfide in the hydroxylated graphene-nano-tungsten disulfide composite material is 0.1-3:0.5-2; and the interlayer spacing of the intercalation structure is 0.45-0.55 nm.

[0014] Preferably, the preparation method of the hydroxylated graphene-nano tungsten disulfide composite material comprises the following steps:

[0015] The hydroxylated graphene and nano-tungsten disulfide are ball-milled to obtain the hydroxylated graphene-nano-tungsten disulfide composite material; the ball-milling process is performed at a rotation speed of 150 to 1250 rpm and for a time of 3 to 16 hours.

[0016] Preferably, the porous silica elastic particles include a porous shell and a cavity encapsulated in the porous shell; the particle size of the porous silica elastic particles is 80-500 mesh, the thickness of the porous shell is 30-80 nm, and the pore size of the porous silica elastic particles is 10-30 nm.

[0017] Preferably, the fluorinated carbon nanotubes are single-walled fluorinated carbon nanotubes or multi-walled fluorinated carbon nanotubes, the length of the fluorinated carbon nanotubes is 10 to 20 μm, the diameter is 40 to 60 nm, and the fluorine content is 35 to 60 wt%; the corrosion inhibitor includes one or more of a benzotriazole corrosion inhibitor, an organic amine corrosion inhibitor, a carboxylic acid corrosion inhibitor, and a phosphate corrosion inhibitor; the base oil includes one or more of a polyalphaolefin base oil, a hydrogenated base oil, and a solvent-refined mineral oil.

[0018] The present invention provides a method for preparing the graphene-based lubricating oil additive described in the above technical solution, comprising the following steps:

[0019] The graphene-based lubricating oil additive is obtained by mixing a hydroxylated graphene-nano tungsten disulfide composite material, nano magnesium aluminum silicate, porous silicon dioxide elastic particles, fluorinated carbon nanotubes, a corrosion inhibitor and a base oil, and performing a dispersion treatment.

[0020] Preferably, the dispersion treatment comprises sequentially performing ultrasonic treatment, shearing treatment and homogenization treatment;

[0021] The ultrasonic treatment conditions include: frequency of 30 to 50 kHz, power of 250 to 350 W, and time of 0.5 to 1.5 h;

[0022] The shearing treatment conditions include: temperature <60°C, rotation speed of 10000-15000 rpm, and time of 20-40 min;

[0023] The number of homogenization treatments is 2-4 times, and the conditions of each homogenization treatment independently include: a pressure of 60-160 MPa, a flow of 500-5000 L / h, and a time of 1-4 h.

[0024] The application provides application of the graphene-based lubricating oil additive in water pump lubrication.

[0025] Preferably, the water pump comprises a reciprocating pump, a plunger pump, a piston pump, a diaphragm pump, a rotor pump, a screw pump, a liquid ring pump, a gear pump, a vane pump, a Roots pump, a roller pump, a cam pump, a peristaltic pump, a turbulence pump, a vane pump, a centrifugal pump, a axial flow pump, a mixed flow pump, a vortex pump, a jet pump, an injection pump, a water hammer pump, a vacuum pump, a volute pump, a hose pump or a worm pump.

[0026] The application provides an anti-wear, noise-reducing and energy-saving lubricant, which comprises lubricating oil and the graphene-based lubricating oil additive.

[0027] The application provides a graphene-based lubricating oil additive, which comprises the following components in percentage by mass: 0.6-5% of a hydroxylated graphene-nano tungsten disulfide composite material, 2-8% of nano magnesium aluminum silicate, 0.3-1.2% of porous silica elastic microparticles, 1-5% of carbon fluoride nanotubes, 0.5-2% of an corrosion inhibitor and the balance of base oil.

[0028] In addition, the conventional water pump lubricating oil usually adopts an organic molybdenum noise-reducing additive, which has poor water resistance and a blade pass frequency (BPF) noise peak value of more than 80 dB(A), and cannot target inhibit the BPF high-frequency noise. In the application, the graphene-based lubricating oil additive is added with porous silica elastic microparticles, so that the BPF can be accurately matched, the noise reduction effect is excellent, and the high-frequency noise suppression effect is improved.

[0029] Furthermore, conventional water pump lubricants are significantly affected by water, and their anti-wear properties decrease by more than 50% after emulsification with water, exacerbating the risk of bearing corrosion. The graphene-based lubricant additives in this invention, by adding fluorinated carbon nanotubes and corrosion inhibitors, effectively block water and oxygen penetration, improving resistance to water contamination and reducing the risk of bearing corrosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 TEM image of the hydroxylated graphene-nano tungsten disulfide composite material in Example 1;

[0031] Figure 2 is the X-ray diffraction pattern of the hydroxylated graphene-nano tungsten disulfide composite material in Example 1;

[0032] Figure 3 This is a SEM image of the oil film formed on the metal parts of the centrifugal pump by the anti-wear, noise-reducing and energy-saving lubricant in Application Example 1;

[0033] Figure 4 This is a SEM image of fluorinated carbon nanotubes on a metal surface after a friction test with the anti-wear, noise-reducing, and energy-saving lubricant in Application Example 1;

[0034] Figure 5 This is the friction coefficient test result of the anti-wear, noise-reducing and energy-saving lubricant in Application Example 1. DETAILED DESCRIPTION

[0035] The present invention provides a graphene-based lubricating oil additive, which comprises the following components by mass percentage:

[0036] 0.6-5% of a hydroxylated graphene-nano tungsten disulfide composite material, wherein the hydroxylated graphene and the nano tungsten disulfide form an interlayer intercalation structure;

[0037] Nano magnesium aluminum silicate 2-8%;

[0038] Porous silica elastic particles 0.3-1.2%;

[0039] Fluorinated carbon nanotubes 1-5%;

[0040] Corrosion inhibitor 0.5-2%;

[0041] Base oil balance.

[0042] In the present invention, unless otherwise specified, the raw materials used are commercially available products well known to those skilled in the art or are prepared using methods well known to those skilled in the art.

[0043] The graphene-based lubricating oil additive of the present invention comprises, by mass percentage, 0.6-5% of the hydroxylated graphene-nano-tungsten disulfide composite material, specifically 0.6%, 0.7%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%. In the hydroxylated graphene-nano-tungsten disulfide composite material of the present invention, the hydroxylated graphene and the nano-tungsten disulfide form an interlayer intercalation structure, and the interlayer spacing of the intercalation structure can be 0.45-0.55 nm; the interlayer spacing of the present invention specifically refers to the spacing between two adjacent layers. As one embodiment of the present invention, the mass ratio of hydroxylated graphene to nano-tungsten disulfide in the hydroxylated graphene-nano-tungsten disulfide composite material can be 0.1-3:0.5-2, further 0.5-1:1-1.5, specifically 0.8:1.2. As one embodiment of the present invention, the grafting rate of hydroxyl groups in the hydroxylated graphene can be 2.5-6%, specifically 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, or 6%. The hydroxylated graphene is specifically obtained by hydroxylating a graphene raw material, and the grafting rate of hydroxyl groups in the hydroxylated graphene specifically refers to the percentage of the mass of hydroxyl groups in the hydroxylated graphene to the mass of the graphene raw material. As one embodiment of the present invention, the lateral dimensions of the nano-tungsten disulfide can be 20-500 nm, and the monolayer ratio is ≥95%. The hydroxylated graphene-nano-tungsten disulfide composite material of the present invention has excellent anti-wear and friction-reducing properties, which helps reduce motor load current and improve energy efficiency. Specifically, the hydrogen bonds of the hydroxylated graphene in the present invention can be anchored on the metal surface, and have good resistance to erosion and wear; nano-tungsten disulfide has a good interlayer slip drag reduction effect; the hydroxylated graphene and nano-tungsten disulfide in the hydroxylated graphene-nano-tungsten disulfide composite material form an interlayer intercalation structure (that is, a heterogeneous structure is also formed at the same time), which is beneficial to reducing shear resistance, and can reduce contact resistance through interlayer electron transmission, improve conductivity, and reduce electrostatic loss and eddy current loss.

[0044] As one embodiment of the present invention, the preparation method of the hydroxylated graphene-nano tungsten disulfide composite material may include the following steps: ball milling the hydroxylated graphene and nano tungsten disulfide to obtain the hydroxylated graphene-nano tungsten disulfide composite material; the rotation speed of the ball milling treatment may be 150 to 1250 rpm, further 180 to 500 rpm, specifically 200 rpm; the time of the ball milling treatment may be 3 to 16 hours, further 3.5 to 8 hours, specifically 4 hours. As one embodiment of the present invention, the ball milling treatment is preferably carried out in a protective atmosphere, and the protective atmosphere may be nitrogen. The present invention can ensure that the hydroxylated graphene and nano tungsten disulfide form an interlayer intercalation structure by ball milling under the above conditions, without the need for additional high-temperature treatment processes, simple operation, and convenient for large-scale production.

[0045] The graphene-based lubricant additive of the present invention comprises 2-8% by mass of nano-magnesium aluminum silicate, specifically 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, or 8%. In one embodiment of the present invention, the particle size of the nano-magnesium aluminum silicate can be 20-100 nm. The nano-magnesium aluminum silicate of the present invention sinters under high temperature (>120°C) in the cavitation micro-region to form a MgAl2O4 ceramic phase, which has the functions of filling cavitation pits and high-temperature ceramic repair.

[0046] In terms of mass percentage, the graphene-based lubricating oil additive of the present invention comprises 0.3-1.2% of porous silica elastic particles, specifically 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1% or 1.2%. As one embodiment of the present invention, the porous silica elastic particles comprise a porous shell and a cavity encapsulated in the porous shell (i.e., the porous silica elastic particles are hollow particles with a shell on the surface, and the shell has a nano-scale porous structure); the particle size of the porous silica elastic particles can be 80-500 mesh, and further can be 300-450 mesh; the thickness of the porous shell can be 30-80 nm, specifically 50 nm; and the pore size of the porous silica elastic particles can be 10-30 nm.

[0047] As an embodiment of the present invention, the damping factor tanδ of the porous silica elastic particles is ≥ 0.5. As an embodiment of the present invention, the damping peak center frequency of the porous silica elastic particles satisfies the requirements of formula I:

[0048] f = √(k / m) / (2π) Formula I;

[0049] Where f is the damping peak center frequency of the porous silica elastic particle; m is the mass of the porous silica elastic particle; k = 3Eπr 3 / (4t 3 ), E is the modulus of the porous shell of the porous silica elastic particle (1-5 GPa), t is the thickness of the porous shell of the porous silica elastic particle (30-80 nm), and r is the radius of the porous silica elastic particle.

[0050] The present invention can regulate the damping peak position of the porous silica elastic particles by adjusting the thickness (t) and elastic modulus (E) of the porous shell layer so that it accurately matches the blade passing frequency (BPF).

[0051] The porous silica elastic particles of the present invention can absorb the high-frequency vibration of the BPF in a targeted manner, and the pores on the porous shell layer thereof have an oil-locking effect, thereby facilitating the maintenance of the continuity of the oil film.

[0052] The graphene-based lubricant additive of the present invention comprises 1-5% of fluorinated carbon nanotubes by mass percentage, specifically 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%. As one embodiment of the present invention, the fluorinated carbon nanotubes are single-walled fluorinated carbon nanotubes or multi-walled fluorinated carbon nanotubes, the length of the fluorinated carbon nanotubes being 10-20 μm, the diameter being 40-60 nm, and the fluorine content being 35-60 wt%, specifically 35 wt%, 40 wt%, 45 wt%, 50 wt%, 55 wt% or 60 wt%. The fluorinated carbon nanotubes described in the present invention can form an electrostatic repulsive layer with a zeta potential greater than -30mV at the oil-water interface, inhibiting the coalescence of water droplets (emulsification tendency index less than 5%, ASTM D1401). Therefore, the fluorinated carbon nanotubes can form a hydrophobic barrier (contact angle greater than 150°) on metal surfaces when used in lubricating oil. Moreover, during the friction process, as the interface layer continuously rotates unidirectionally at high speed, the fluorinated carbon nanotubes can achieve directional alignment in the oil film near the friction pair and guide the distribution of porous silica elastic particles, thereby facilitating the improvement of the friction pair interface.

[0053] In terms of mass percentage, the graphene-based lubricant additive of the present invention includes 0.5-2% of corrosion inhibitor, specifically 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8% or 2%. As an embodiment of the present invention, the corrosion inhibitor may include one or more of a benzotriazole (BTA) corrosion inhibitor, an organic amine corrosion inhibitor, a carboxylic acid corrosion inhibitor and a phosphate corrosion inhibitor; the organic amine corrosion inhibitor may include dodecylamine and / or cyclohexylamine, the carboxylic acid corrosion inhibitor may include oleic acid and / or stearic acid, and the phosphate corrosion inhibitor may include triethyl phosphate; the corrosion inhibitor used in the embodiment of the present invention may be a BTA corrosion inhibitor, specifically a BTA-12 corrosion inhibitor. The corrosion inhibitor in the embodiment of the present invention has a passivating effect on the metal surface, and its synergistic effect with the fluorinated carbon nanotubes can effectively block water and oxygen penetration.

[0054] The graphene-based lubricant additive of the present invention includes a base oil as a balance, calculated by mass percentage. In one embodiment of the present invention, the base oil may include one or more of a polyalphaolefin base oil, a hydrogenated base oil, and a solvent-refined mineral oil, and may specifically be a polyalphaolefin base oil. The polyalphaolefin base oil may specifically be one or more of PAO4, PAO6, PAO8, and mPAO150, and may specifically be PAO6.

[0055] The application provides a preparation method of the graphene-based lubricating oil additive.

[0056] The graphene-based lubricating oil additive is prepared by mixing hydroxylated graphene-nano tungsten disulfide composite material, nano magnesium aluminum silicate, porous silica elastic microparticles, carbon fluoride nanotubes, corrosion inhibitor and base oil, and performing dispersion treatment.

[0057] As an embodiment of the application, the dispersion treatment can include ultrasonic treatment, shear treatment and homogenization treatment in sequence. As an embodiment of the application, the ultrasonic treatment can be performed once under the following conditions: the frequency is 30-50 kHz, specifically 40 kHz; the power is 250-350 W, specifically 300 W; and the time is 0.5-1.5 h, specifically 1 h. As an embodiment of the application, the shear treatment can be performed once under the following conditions: the temperature is <60 ℃, further 50-55 ℃; the rotation speed is 10,000-15,000 rpm, specifically 12,000 rpm; and the time is 20-40 min, specifically 30 min. As an embodiment of the application, the homogenization treatment can be performed 2-4 times, specifically 3 times, and each time of the homogenization treatment can be independently performed under the following conditions: the pressure is 60-160 MPa, further 120-155 MPa, specifically 150 MPa; the flow rate is 500-5,000 L / h, further 2,000-3,500 L / h, specifically 3,000 L / h; and the time is 1-4 h, further 1.5-2.5 h, specifically 2 h. The dispersion treatment under the above conditions can mix the components uniformly and make the D50 particle size of the solid material in the graphene-based lubricating oil additive ≤200 nm.

[0058] The application provides an application of the graphene-based lubricating oil additive in water pump lubrication. As an embodiment of the application, the water pump can include reciprocating pump, plunger pump, piston pump, diaphragm pump, rotor pump, screw pump, liquid ring pump, gear pump, vane pump, Roots pump, roller pump, cam pump, peristaltic pump, eccentric pump, vane pump, centrifugal pump, axial flow pump, mixed flow pump, vortex pump, jet pump, injection pump, water hammer pump, vacuum pump, volute pump, hose pump or worm pump. The graphene-based lubricating oil additive of the application can be used in the Cl - high-concentration working condition and still maintain excellent comprehensive performance, for example, the Cl - concentration can be >20,000 ppm.

[0059] The present invention provides an anti-wear, noise-reducing and energy-saving lubricant, comprising lubricating oil and the graphene-based lubricating oil additive described in the above technical solution or the graphene-based lubricating oil additive prepared by the preparation method described in the above technical solution, wherein the mass content of the graphene-based lubricating oil additive in the anti-wear, noise-reducing and energy-saving lubricant is 3-12%, specifically 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11% or 12%. As one embodiment of the present invention, the anti-wear, noise-reducing and energy-saving lubricant can be a water pump lubricant, and the water pumps suitable for the water pump lubricant can include reciprocating pumps, plunger pumps, piston pumps, diaphragm pumps, rotor pumps, screw pumps, liquid ring pumps, gear pumps, vane pumps, Roots pumps, roller pumps, cam pumps, peristaltic pumps, perturbation pumps, vane pumps, centrifugal pumps, axial flow pumps, mixed flow pumps, vortex pumps, jet pumps, jet pumps, water hammer pumps, vacuum pumps, volute pumps, hose pumps or worm pumps. As an embodiment of the present invention, the lubricating oil may include hydraulic oil, internal combustion engine lubricating oil, gear oil or metalworking oil; the hydraulic oil may be 46# hydraulic oil.

[0060] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0061] The sources of some of the raw materials used in the following examples and comparative examples are shown in Table 1.

[0062] Table 1 Index parameters of some raw materials used in the examples and comparative examples

[0063]

[0064] Unless otherwise specified, the following examples and comparative examples were all operated at room temperature (20-25° C.).

[0065] Example 1

[0066] The hydroxylated graphene and nano-tungsten disulfide were placed in a ball mill at a mass ratio of 0.8:1.2, and ball milled for 4 hours at a speed of 200 rpm under nitrogen protection to form an intercalated structure with an interlayer spacing of 0.45 to 0.55 nm, thereby obtaining a hydroxylated graphene-nano-tungsten disulfide composite material;

[0067] The graphene-based lubricating oil additive was prepared by mixing 2% hydroxylated graphene-nano tungsten disulfide composite, 5% nano magnesium aluminum silicate, 0.9% porous silica elastic microparticles, 3% carbon fluoride nanotubes, 1.5% BTA-12 corrosion inhibitor and the balance of PAO6 base oil (purchased from China Petroleum Chemical Group Co., Ltd.) in mass percentage, and then sequentially performing ultrasonic treatment (1 time), shear treatment (1 time) and homogenization treatment (3 times). The frequency of the ultrasonic treatment was 40 kHz, the power was 300 W, and the time was 1 h. The temperature of the shear treatment was not more than 55°C, the rotation speed was 12000 rpm, and the time was 30 min. The pressure of each homogenization treatment was 150 MPa, the flow rate was 3000 L / h, and the time was 2 h. The D50 particle size of the solid material in the graphene-based lubricating oil additive was ≤200 nm.

[0068] Figure 1 The TEM image of the hydroxylated graphene-nano tungsten disulfide composite in Example 1 showed that the hydroxylated graphene and nano tungsten disulfide formed a clear intercalation structure, and the interlayer spacing of the intercalation structure was 0.45-0.55 nm.

[0069] Figure 2 The X-ray diffraction pattern of the hydroxylated graphene-nano tungsten disulfide composite in Example 1 showed a relatively obvious characteristic peak of the hydroxylated graphene-nano tungsten disulfide composite.

[0070] Examples 2-4

[0071] The graphene-based lubricating oil additive was prepared by the method of Reference Example 1, except that the formulations were different. The formulations of the graphene-based lubricating oil additives in each example were specifically listed in Table 2.

[0072] Table 2 Formulations of graphene-based lubricating oil additives in each example

[0073]

[0074] Comparative Examples 1-4

[0075] The lubricating oil additive was prepared by the method of Reference Example 1, except that the formulations were different. The formulations of the lubricating oil additives in each example were specifically listed in Table 3.

[0076] Table 3 Formulations of lubricating oil additives in Comparative Examples 1-4

[0077]

[0078] Comparative Example 5

[0079] The lubricating oil additive was prepared according to the method of Example 1, except that the hydroxylated graphene-nano-tungsten disulfide composite material was replaced by a mixture of hydroxylated graphene and nano-tungsten disulfide, that is, the ball milling treatment was not performed to form an intercalated structure, and the hydroxylated graphene and nano-tungsten disulfide were directly mixed with other raw materials. The lubricating oil additive was then subjected to ultrasonic treatment (1 time), shear treatment (1 time), and homogenization treatment (3 times) in sequence to obtain the lubricating oil additive.

[0080] Application Examples 1 to 4

[0081] The graphene-based lubricating oil additives in Examples 1 to 4 were respectively mixed with 46# hydraulic oil (purchased from China Petrochemical Corporation) to prepare an anti-wear, noise-reducing and energy-saving lubricant; the mass content of the graphene-based lubricating oil additive in the anti-wear, noise-reducing and energy-saving lubricant was 10%.

[0082] Comparative Application Examples 1 to 5

[0083] The lubricating oil additives in Comparative Examples 1 to 5 were respectively mixed with 46# hydraulic oil (purchased from China Petrochemical Corporation) to prepare lubricants; the mass content of the lubricating oil additives in the lubricants was 10%.

[0084] Test Example 1

[0085] The anti-wear, noise-reducing and energy-saving lubricant in Application Example 1 was used to lubricate a centrifugal pump. After the centrifugal pump had been operating normally for 24 hours, the anti-wear, noise-reducing and energy-saving lubricant was released. The centrifugal pump was disassembled and observed. An oil film was found to be formed on the surface of the metal parts of the centrifugal pump. The results were as follows: Figure 3 shown.

[0086] Figure 3 This is an SEM image of the oil film formed on the surface of the metal parts of the centrifugal pump by the anti-wear, noise-reducing and energy-saving lubricant in Application Example 1. The results show that the anti-wear, noise-reducing and energy-saving lubricant is prepared using the graphene-based lubricating oil additive in Example 1 of the present invention. When the lubricant is used in a centrifugal pump, the added components in the oil film formed are relatively evenly dispersed.

[0087] Test Example 2

[0088] According to the method in GB / T 11144, the anti-wear, noise reduction and energy-saving lubricant prepared in Application Example 1 was subjected to a friction test. After the experiment, the metal ring block was taken out and its surface was characterized. The results are as follows: Figure 4 shown.

[0089] Figure 4 This is the SEM image of the fluorinated carbon nanotubes on the metal surface after the friction test of the anti-wear, noise-reducing and energy-saving lubricant in Application Example 1. The results show that the fluorinated carbon nanotubes are oriented on the metal surface, forming a relatively regularly arranged surface and interface nanostructure.

[0090] Test Example 3: Centrifugal Pump Industrial Test

[0091] The lubricants formulated in each application example and comparative application example were used in centrifugal pumps to test the performance of each lubricant additive. The friction coefficient was tested according to ASTM D5183, the current was obtained from the voltage according to the method in GB / T3216, the cavitation detection was tested according to GB / T 13006, the noise was tested according to GB / T 39959, and the PB value was tested according to GB / T 3142. The test results are shown in Table 4. Figure 5 This figure shows the friction coefficient test results for the anti-wear, noise-reducing, and energy-saving lubricant in Application Example 1. The results show that compared with the comparative example, the graphene-based lubricant additive in the embodiment of the present invention has excellent overall performance, including a lower friction coefficient, lower current, fewer impeller cavitation pits, lower 800Hz noise, and a higher PB value.

[0092] Table 4 Centrifugal pump industrial test results

[0093]

[0094] In addition, taking the graphene-based lubricating oil additive in Example 1 as an example, the correlation between the current increase and the friction coefficient was studied under the above test conditions. Specifically, the current increase obtained by the measurement and the friction coefficient were linearly fitted to obtain a linear regression equation of the two. The linear regression equation is specifically: current increase = 0.85 + 9.27 × friction coefficient, R 2 =0.96. This indicates that the current increase is strongly correlated with the friction coefficient, and a larger friction coefficient leads to a larger current increase.

[0095] Test Example 4: Long-term test of plunger pump

[0096] The lubricants prepared in each application example and comparative application example were used in a plunger pump, and their current fluctuation was tested. The current was calculated based on the voltage according to the method in GB / T3216. The results are shown in Table 5. The results show that the current fluctuation rate is lower when the graphene-based lubricant additive in the embodiment of the present invention is used compared with the comparative example.

[0097] Table 5 Plunger pump long-term (aging 4000h) test results

[0098]

[0099]

[0100] In summary, the graphene-based lubricant additive provided by the present invention is a multifunctional integrated lubricant additive. Through the synergistic effect of tribology, acoustics, and electrochemistry, it can simultaneously achieve the integrated functions of in-situ repair of cavitation damage, anti-wear and drag reduction, motor load current reduction, and noise reduction, and is suitable for water pump lubrication. Specifically, the graphene-based lubricant additive provided by the present invention has at least the following beneficial effects: (1) Energy saving: motor current is reduced by 8-15%, and annual power consumption is reduced by more than 12%; (2) Quiet: Directed suppression of noise in the 500-2000Hz frequency band, A-weighted noise ≤78dB; (3) Long life: In-situ repair of cavitation micro-areas reduces impeller damage by ≥70%, and the life of the impeller and bearing is extended to 2.5 times; (4) Environmental tolerance: supports operation in a wide temperature range of -30-150℃ and IP68 waterproof level; excellent anti-friction performance, and PB value retention rate >90%.

[0101] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A graphene-based lubricant additive comprising the following components by mass percentage: 0.6-5% of a hydroxylated graphene-nano tungsten disulfide composite material, wherein the hydroxylated graphene and the nano tungsten disulfide form an interlayer intercalation structure; Nano magnesium aluminum silicate 2-8%; Porous silica elastic particles 0.3-1.2%; Fluorinated carbon nanotubes 1-5%; Corrosion inhibitor 0.5-2%; Base oil balance.

2. The graphene-based lubricating oil additive according to claim 1, characterized in that The mass ratio of hydroxylated graphene to nano-tungsten disulfide in the hydroxylated graphene-nano-tungsten disulfide composite material is 0.1-3:0.5-2; and the interlayer spacing of the intercalation structure is 0.45-0.55 nm.

3. The graphene-based lubricating oil additive according to claim 1 or 2, characterized in that The preparation method of the hydroxylated graphene-nano tungsten disulfide composite material comprises the following steps: The hydroxylated graphene and nano-tungsten disulfide are ball-milled to obtain the hydroxylated graphene-nano-tungsten disulfide composite material; the ball-milling process is performed at a rotation speed of 150 to 1250 rpm and for a time of 3 to 16 hours.

4. The graphene-based lubricating oil additive according to claim 1, characterized in that The porous silica elastic particles include a porous shell layer and a cavity enclosed in the porous shell layer; the particle size of the porous silica elastic particles is 80 to 500 meshes, the thickness of the porous shell layer is 30 to 80 nm, and the pore size of the porous silica elastic particles is 10 to 30 nm.

5. The graphene-based lubricating oil additive according to claim 1, characterized in that The fluorinated carbon nanotubes are single-walled fluorinated carbon nanotubes or multi-walled fluorinated carbon nanotubes, and the length of the fluorinated carbon nanotubes is 10 to 20 μm, the diameter is 40 to 60 nm, and the fluorine content is 35 to 60 wt%; the corrosion inhibitor includes one or more of benzotriazole corrosion inhibitors, organic amine corrosion inhibitors, carboxylic acid corrosion inhibitors and phosphate corrosion inhibitors; and the base oil includes one or more of polyalphaolefin base oil, hydrogenated base oil and solvent refined mineral oil.

6. A method for preparing the graphene-based lubricating oil additive according to any one of claims 1 to 5, comprising the following steps: The graphene-based lubricating oil additive is obtained by mixing a hydroxylated graphene-nano tungsten disulfide composite material, nano magnesium aluminum silicate, porous silicon dioxide elastic particles, fluorinated carbon nanotubes, a corrosion inhibitor and a base oil, and performing a dispersion treatment.

7. The preparation method according to claim 6, characterized in that The dispersion treatment includes sequentially performing ultrasonic treatment, shearing treatment and homogenization treatment; The ultrasonic treatment conditions include: frequency of 30 to 50 kHz, power of 250 to 350 W, and time of 0.5 to 1.5 h; The shearing treatment conditions include: temperature <60°C, rotation speed of 10000-15000 rpm, and time of 20-40 min; The homogenization treatment is performed 2 to 4 times, and the conditions of each homogenization treatment independently include: a pressure of 60 to 160 MPa, a flow rate of 500 to 5000 L / h, and a time of 1 to 4 hours.

8. Use of the graphene-based lubricating oil additive according to any one of claims 1 to 5 or the graphene-based lubricating oil additive prepared by the preparation method according to claim 6 or 7 in water pump lubrication.

9. The use according to claim 8, characterized in that The water pump includes a reciprocating pump, a plunger pump, a piston pump, a diaphragm pump, a rotor pump, a screw pump, a liquid ring pump, a gear pump, a vane pump, a Roots pump, a roller pump, a cam pump, a peristaltic pump, a perturbation pump, a vane pump, a centrifugal pump, an axial flow pump, a mixed flow pump, a vortex pump, a jet pump, a jet pump, a water hammer pump, a vacuum pump, a volute pump, a hose pump or a worm pump.

10. An anti-wear, noise-reducing and energy-saving lubricant, comprising lubricating oil and the graphene-based lubricating oil additive according to any one of claims 1 to 5 or the graphene-based lubricating oil additive prepared by the preparation method according to claim 6 or 7, wherein the mass content of the graphene-based lubricating oil additive in the anti-wear, noise-reducing and energy-saving lubricant is 3 to 12%.

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