An in-situ method of achieving oil-based liquid super-slip in a super-slip system

Abstract

An in-situ oil-based liquid superlubrication method is realized in a superlubrication system. The superlubrication system uses any one of silicon nitride, silicon dioxide, zirconium oxide or tungsten steel as a friction pair, uses an oil-based liquid as a lubricant, and pre-adds or coats a pre-rubbing lubricating liquid on the surface of the friction pair. The pre-rubbing lubricating liquid consists of the following components by weight percentage: a friction modifier: 0.01% to 15.0%, and the balance of a polyhydric fatty alcohol. The in-situ oil-based liquid superlubrication method comprises: 1) adding the pre-rubbing lubricating liquid to the surface of the friction pair and rubbing; 2) after cleaning the surface of the friction pair, adding the oil-based liquid to the surface of the friction pair obtained in step 1), so as to realize the in-situ oil-based liquid superlubrication. The method described in the application has realized the robust superlubrication of various oil-based liquids on the surface of the carbon-based film.

Description

Technical Field

[0001] This article relates to the field of lubrication materials technology, specifically to a superlubricating system and a method for achieving in-situ superlubricity of oil-based liquids. Background Technology

[0002] Carbon-based thin films are a novel material possessing both strength and lubrication properties. Carbon-based thin film materials can effectively reduce friction and wear on components, thus finding wide applications in aerospace, aviation, and deep-sea vessels. With the emergence of the superlubricity concept, achieving robust superlubricity in carbon-based thin films has become a hot research topic both domestically and internationally, particularly the realization of oil-based liquid superlubricity on carbon-based thin film surfaces. Among these, oil-based lubrication systems, due to their high thermal stability, low volatility, and resistance to environmental humidity, are among the most valuable superlubricity systems for engineering applications. Furthermore, the waste liquid from oil-based lubricants can be recycled, deeply aligning with my country's green and sustainable development philosophy.

[0003] However, the high chemical inertness of carbon-based thin films makes it difficult for them to undergo tribochemical reactions with oil-based liquids, thus preventing them from achieving superlubricity. Summary of the Invention

[0004] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0005] To address the aforementioned technical challenges, this application innovates a path to achieve super-lubricating effects, providing a pre-running lubricant for carbon-based thin films that achieves super-lubricity of oil-based liquids, its preparation method, a super-lubricating system, and a method for achieving super-lubricity of oil-based liquids in situ. The method described in this application has achieved robust super-lubricity of various oil-based liquids on the surface of carbon-based thin films.

[0006] The first aspect of this application provides a pre-running lubricant, which comprises, by weight percentage: friction modifier: 0.01%-15.0%, and the balance being polyfatty alcohol.

[0007] In one exemplary embodiment, the pre-run-in lubricant comprises, by weight percentage, the following components: friction modifier: 0.01%-15.0%, and the balance being polyfatty alcohol.

[0008] In one exemplary embodiment, the friction modifier is C 1-10 Alkyl sulfates and C 1-10 One or two of alkyl sulfites; preferably C 1-8 Alkyl sulfates and C 1-8 One or two of alkyl sulfites, more preferably C 1-5 Alkyl sulfates and C 1-5 One or two of alkyl sulfites.

[0009] In one exemplary embodiment, the structure of the alkyl sulfate is: R 1 O-SO2-OR 2 , where R 1 With R 2 For the same or different C 1-5 alkyl.

[0010] In one exemplary embodiment, the structure of the alkyl sulfite is: R 3 OS(=O)-OR 4 , where R 3 With R 4 For the same or different C 1-5 alkyl.

[0011] In one exemplary embodiment, the alkyl sulfate is selected from one or more of diethyl sulfate, dipropyl sulfate, dibutyl sulfate, and dipentyl sulfate in any proportion.

[0012] In one exemplary embodiment, the alkyl sulfite is selected from one or more of diethyl sulfite, dipropyl sulfite, dibutyl sulfite, and dipentyl sulfite in any proportion.

[0013] In one exemplary embodiment, the polyfatty alcohol is one or more fatty alcohols in any proportion having 2-20 carbon atoms and at least 2 hydroxyl groups. The term "polyfatty alcohol" as used herein includes chain hydrocarbon polyols and cyclic polyols, wherein the chain hydrocarbon polyol optionally includes one or more ether groups, olefin groups, or alkyne groups.

[0014] In one exemplary embodiment, the polyhydroxy alcohol may be selected from one or more of triethylene glycol, ethylene glycol, propylene glycol (e.g., 1,3-propanediol, 1,2-propanediol), and glycerol (e.g., 1,3-propanediol, 1,2-propanediol).

[0015] In one exemplary embodiment, the friction modifier is selected from one or both of dipropyl sulfite and diethyl sulfate.

[0016] In one exemplary embodiment, the pre-run-in lubricant comprises, by weight percentage: 10% dipropyl sulfite and the balance triethylene glycol; or

[0017] The pre-run-in lubricant, by weight percentage, comprises the following components: 2% dipropyl sulfite, 3% diethyl sulfate, and the balance ethylene glycol; or

[0018] The pre-running lubricant is composed of the following components by weight percentage: 2% dipropyl sulfite, 3% diethyl sulfate, 5% glycerol, 30% ethylene glycol, 10% propylene glycol, and 50% triethylene glycol.

[0019] The second aspect of this application provides a method for preparing the above-mentioned pre-running lubricant, comprising: mixing a friction modifier and a polyfatty alcohol uniformly according to a ratio to obtain the pre-running lubricant.

[0020] The third aspect of this application provides a pre-running lubricant prepared by the above method.

[0021] The fourth aspect of this application provides a superlubricating system, wherein the superlubricating system uses any one of silicon nitride, silicon dioxide, zirconium oxide or tungsten steel and a carbon-based thin film as a friction pair, uses an oil-based liquid as a lubricant, and pre-drips or coats the pre-running lubricant onto the surface of the friction pair.

[0022] In one exemplary embodiment, the oil-based liquid is an unsaturated oil-based liquid;

[0023] Optionally, the oil-based liquid is selected from one or more of oleic acid, castor oil, soybean oil, polyalphaolefin (PAO), and silicone oil in any proportion;

[0024] Optionally, the polyα-olefin is selected from one or more of PAO 2, PAO 4 and PAO 10 in any proportion;

[0025] Optionally, the silicone oil is selected from one or more of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, fluorinated silicone oil and amino silicone oil in any proportion.

[0026] In one exemplary embodiment, the superlubricating system uses a carbon-based thin film / silicon nitride ceramic as a friction pair.

[0027] In one exemplary embodiment, the carbon-based thin film is a hydrogen-free amorphous carbon-based thin film;

[0028] Optionally, the carbon-based thin film is selected from at least one of amorphous carbon-based thin films (aC) and tetrahedral amorphous carbon-based thin films (ta-C).

[0029] The fifth aspect of this application provides a method for achieving in-situ superlubricity of oil-based liquids in the aforementioned superlubricating system, the method comprising:

[0030] 1) The pre-run-in lubricant is dripped or coated onto the surface of the friction pair and then run-in;

[0031] 2) After cleaning the surface of the friction pair, the oil-based liquid is dripped onto the surface of the friction pair obtained in step 1), so that the oil-based liquid can achieve in-situ superlubricity in the superlubricating system.

[0032] In one exemplary embodiment, step 1) includes: dripping or coating the pre-running lubricant onto the surface of the friction pair and running it for 0-120 minutes at a rotational speed of v1 and a Hertzian contact stress of P1, wherein the running time does not include 0.

[0033] In an exemplary embodiment, step 2) includes: after cleaning the surface of the friction pair, the oil-based liquid is dripped onto the surface of the friction pair obtained in step 1), and friction is performed under the conditions of rotational speed v2 and Hertzian contact stress P2, so that the oil-based liquid superlubricity can be achieved in situ in the superlubricating system.

[0034] In one exemplary embodiment, the ranges of the rotational speeds v1 and v2 are:

[0035] 0mm / s≤v1≤300mm / s, 0mm / s≤v2≤1000mm / s, and satisfy v1≤v2.

[0036] In one exemplary embodiment, the ranges of the Hertzian contact stresses P1 and P2 are:

[0037] 0MPa<P1≤2000MPa, 0MPa<P2≤500MPa, and satisfy P1≥P2.

[0038] In one exemplary embodiment, the method includes the following steps:

[0039] 1) The pre-running lubricant is dropped onto or coated onto the surface of an amorphous carbon-based thin film aC / silicon nitride ceramic pair and run for 10 minutes under the conditions of a rotation speed of 31.4 mm / s and a Hertzian contact stress of 1.5 GPa; wherein the pre-running lubricant is composed of the following components by weight percentage: 10% dipropyl sulfite and the balance triethylene glycol;

[0040] 2) After cleaning the surface of the amorphous carbon-based thin film aC / silicon nitride ceramic pair, methyl silicone oil is dropped onto the surface of the carbon-based thin film / silicon nitride ceramic pair obtained in step 1). Friction is performed under the conditions of a rotation speed of 62.8 mm / s and a Hertzian contact stress of 89 MPa, so that oil-based liquid superlubricity can be achieved in situ in the superlubricating system.

[0041] In one exemplary embodiment, the method includes:

[0042] 1) The pre-running lubricant is dropped or coated onto the surface of the tetrahedral amorphous carbon-based thin film ta-C / silicon nitride ceramic pair and run for 10 minutes under the conditions of a rotation speed of 31.4 mm / s and a Hertzian contact stress of 1.5 GPa; wherein the pre-running lubricant is composed of the following components by weight percentage: 2% dipropyl sulfite, 3% diethyl sulfate and the balance ethylene glycol;

[0043] 2) After cleaning the surface of the tetrahedral amorphous carbon-based thin film ta-C / silicon nitride ceramic pair, PAO 4 is dropped onto the surface of the tetrahedral amorphous carbon-based thin film ta-C / silicon nitride ceramic pair. Friction is performed under the conditions of a rotation speed of 62.8 mm / s and a Hertzian contact stress of 90 MPa, so that oil-based liquid superlubricity can be achieved in situ in the superlubricating system.

[0044] In one exemplary embodiment, the method includes:

[0045] 1) The pre-running lubricant is dropped or coated onto the surface of the amorphous carbon-based thin film aC / silicon nitride ceramic pair and run for 10 minutes under the conditions of a rotation speed of 31.4 mm / s and a Hertzian contact stress of 1.5 GPa; wherein the pre-running lubricant is composed of the following components by weight percentage: 2% dipropyl sulfite, 3% diethyl sulfate, 5% glycerol, 30% ethylene glycol, 10% propylene glycol, and 50% triethylene glycol;

[0046] 2) After cleaning the surface of the amorphous carbon-based thin film aC / silicon nitride ceramic pair, an oil-based liquid is dropped onto the surface of the amorphous carbon-based thin film aC / silicon nitride ceramic pair. Friction is performed under the conditions of a rotation speed of 62.8 mm / s and a Hertzian contact stress of 87 MPa. In-situ superlubricity of the oil-based liquid can be achieved in the superlubricating system. The oil-based liquid is composed of the following components by weight percentage: 2% oleic acid, 20% methyl silicone oil, 50% PAO 2, and 28% PAO 4.

[0047] This application has the following technical advantages:

[0048] 1. This application provides a method for achieving in-situ superlubricity of oil-based liquids in a superlubricating system, which solves the technical problem that it is difficult to achieve superlubricity of oil-based liquids on the surface of carbon-based thin films. Robust superlubricity of various oil-based liquids and their mixtures on the surface of carbon-based thin films / silicon nitride pairs has been achieved.

[0049] 2. The superlubricating system and the method for achieving superlubricity of oil-based liquids in situ have excellent adaptability to a variety of carbon-based thin films, are independent of the coating preparation method, and have low sensitivity to parameters such as coating surface roughness and adhesion, thus having broad industrial application value.

[0050] 3. The superlubricating system and the method for achieving superlubricity of oil-based liquids in situ in this application involve oil-based liquids with high adaptability. Combined with actual industrial lubrication environments, the friction coefficient can be controlled and adjusted through reasonable design of components and contents.

[0051] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the application. Other advantages of this application can be realized and obtained by means of the solutions described in the description and the accompanying drawings. Attached Figure Description

[0052] The accompanying drawings are used to provide an understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0053] Figure 1 The curve of the superlubricated friction coefficient obtained in Example 1;

[0054] Figure 2 The curve of the super-slippery friction coefficient obtained in Example 2;

[0055] Figure 3 The curve of the super-slippery friction coefficient obtained in Example 3. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in detail below. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be arbitrarily combined with each other.

[0057] The present invention will be further described in detail below with reference to specific examples, but these examples should not be construed as limiting the present invention. All raw materials used in this application are conventional products available on the market.

[0058] Example 1

[0059] Pre-run-in lubricant: Mix 10% dipropyl sulfite and the balance triethylene glycol by weight to obtain the pre-run-in lubricant.

[0060] Oil-based liquid: methyl silicone oil

[0061] Methods for achieving superlubricity in oil-based liquids in situ:

[0062] 1) The pre-running lubricant prepared above was dropped onto the surface of the amorphous carbon-based thin film aC / silicon nitride ceramic pair and run for 10 minutes under the conditions of a rotation speed of 31.4 mm / s and a Hertzian contact stress of 1.5 GPa.

[0063] 2) After cleaning the surface of the amorphous carbon-based thin film aC / silicon nitride ceramic pair, methyl silicone oil is dropped onto the surface of the amorphous carbon-based thin film aC / silicon nitride ceramic pair. Friction is performed under the conditions of a rotation speed of 62.8 mm / s and a Hertzian contact stress of 89 MPa to achieve in-situ superlubricity.

[0064] Example 2

[0065] Pre-run-in lubricant: Mix 2% dipropyl sulfite, 3% diethyl sulfate and 95% ethylene glycol by weight to obtain the pre-run-in lubricant.

[0066] Oil-based liquid: PAO 4

[0067] Methods for achieving superlubricity in oil-based liquids in situ:

[0068] 1) The pre-running lubricant prepared above was dropped onto the surface of the tetrahedral amorphous carbon-based thin film ta-C / silicon nitride ceramic pair and run for 10 minutes under the conditions of a rotation speed of 31.4 mm / s and a Hertzian contact stress of 1.5 GPa.

[0069] 2) After cleaning the surface of the tetrahedral amorphous carbon-based thin film ta-C / silicon nitride ceramic pair, PAO 4 base oil is dropped onto the surface of the tetrahedral amorphous carbon-based thin film ta-C / silicon nitride ceramic pair. Friction is performed under the conditions of a rotation speed of 62.8 mm / s and a Hertzian contact stress of 90 MPa to achieve in-situ superlubricity.

[0070] Example 3

[0071] Pre-run-in lubricant: Mix 2% dipropyl sulfite, 3% diethyl sulfate, 5% glycerol, 30% ethylene glycol, 10% propylene glycol and 50% triethylene glycol by weight percentage to obtain the pre-run-in lubricant.

[0072] Oil-based liquid: Mix 2% oleic acid, 20% methyl silicone oil, 50% PAO 2 base oil and 28% PAO 4 base oil evenly by weight percentage to obtain the oil-based liquid.

[0073] Methods for achieving superlubricity in oil-based liquids in situ:

[0074] 1) The pre-running lubricant prepared above was dropped onto the surface of the amorphous carbon-based thin film aC / silicon nitride ceramic pair and run for 10 minutes under the conditions of a rotation speed of 31.4 mm / s and a Hertzian contact stress of 1.5 GPa.

[0075] 2) After cleaning the surface of the amorphous carbon-based thin film aC / silicon nitride ceramic pair, the above-mentioned oil-based liquid is dropped onto the surface of the amorphous carbon-based thin film aC / silicon nitride ceramic pair. Friction is performed under the conditions of a rotation speed of 62.8 mm / s and a Hertzian contact stress of 87 MPa to achieve in-situ superlubricity.

[0076] Figures 1 to 3 The results are shown for examples 1-3 respectively:

[0077] Figures 1 to 3 Each step consists of two steps, namely step 1 and step 2, which are separated by the horizontal axis at 600s-800s in the figure. Step 1 is a graph showing the change of COF (coefficient of friction) over time during the process of treating the surface of the friction pair composed of carbon-based thin film and silicon nitride ceramic with the pre-running lubricant of the present invention. Step 2 is a graph showing that after cleaning the surface of the friction pair and dripping oil-based liquid after step 1, the average COF of the friction pair surface is about 0.01, which realizes the super-lubricity of the oil-based liquid.

[0078] The above embodiments are preferred embodiments of the present invention, but the implementation of the present invention is not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and are included within the protection scope of the present invention.

Claims

1. A method for achieving in-situ superlubricity of oil-based liquids in a superlubricating system, characterized in that, The superlubricating system uses silicon nitride and carbon-based thin films as friction pairs, oil-based liquids as lubricants, and pre-applies or coats a pre-run-in lubricant onto the surfaces of the friction pairs; the method includes: 1) The pre-running lubricant is dripped or coated onto the surface of the friction pair and run for 0-120 minutes under the conditions of rotational speed v1 and Hertzian contact stress P1, wherein the running time here does not include 0; 2) After cleaning the surface of the friction pair, the oil-based liquid is dripped onto the surface of the friction pair obtained in step 1), and friction is performed under the conditions of rotational speed v2 and Hertzian contact stress P2, so that the oil-based liquid can achieve in-situ superlubricity in the superlubricating system; The pre-run-in lubricant, by weight percentage, comprises the following components: 10% dipropyl sulfite and the balance triethylene glycol; or The pre-run-in lubricant, by weight percentage, comprises the following components: 2% dipropyl sulfite, 3% diethyl sulfate, and the balance ethylene glycol; or The pre-run-in lubricant comprises, by weight percentage, the following components: 2% dipropyl sulfite, 3% diethyl sulfate, 5% glycerol, 30% ethylene glycol, 10% propylene glycol, and 50% triethylene glycol; The oil-based liquid is selected from one or more of oleic acid, polyalphaolefin and silicone oil in any proportion; The poly-α-olefin is selected from one or more of PAO 2, PAO 4 and PAO 10 in any proportion; The silicone oil is selected from one or more of methyl silicone oil, ethyl silicone oil, phenyl silicone oil, fluorinated silicone oil and amino silicone oil in any proportion; 0 mm / s ≤ v1 ≤ 300 mm / s, 0 mm / s ≤ v2 ≤ 1000 mm / s, and satisfy v1 ≤ v2: 0 MPa < P1 ≤ 2000 MPa, 0 MPa < P2 ≤ 500 MPa, and P1 ≥ P2.

2. The method according to claim 1, characterized in that, The carbon-based thin film is a hydrogen-free amorphous carbon-based thin film.

3. The method according to claim 2, characterized in that, The carbon-based thin film is selected from at least one of amorphous carbon-based thin film aC and tetrahedral amorphous carbon-based thin film ta-C.

4. The method according to any one of claims 1 to 3, characterized in that, The method includes the following steps: 1) The pre-running lubricant is dropped onto or coated onto the surface of an amorphous carbon-based thin film aC / silicon nitride ceramic pair and run for 10 minutes under the conditions of a rotation speed of 31.4 mm / s and a Hertzian contact stress of 1.5 GPa; wherein the pre-running lubricant is composed of the following components by weight percentage: 10% dipropyl sulfite and the balance triethylene glycol; 2) After cleaning the surface of the amorphous carbon-based thin film aC / silicon nitride ceramic pair, methyl silicone oil is dropped onto the surface of the carbon-based thin film aC / silicon nitride ceramic pair obtained in step 1). Friction is then performed under conditions of a rotation speed of 62.8 mm / s and a Hertzian contact stress of 89 MPa. This allows for in-situ superlubricity of the oil-based liquid in the superlubricating system; or The method includes: 1) The pre-running lubricant is dropped or coated onto the surface of the tetrahedral amorphous carbon-based thin film ta-C / silicon nitride ceramic pair and run for 10 minutes under the conditions of a rotation speed of 31.4 mm / s and a Hertzian contact stress of 1.5 GPa; wherein the pre-running lubricant is composed of the following components by weight percentage: 2% dipropyl sulfite, 3% diethyl sulfate and the balance ethylene glycol; 2) After cleaning the surface of the tetrahedral amorphous carbon-based thin film ta-C / silicon nitride ceramic pair, PAO 4 is dropped onto the surface of the tetrahedral amorphous carbon-based thin film ta-C / silicon nitride ceramic pair. Friction is then performed under conditions of a rotation speed of 62.8 mm / s and a Hertzian contact stress of 90 MPa. This allows for in-situ superlubricity of the oil-based liquid in the superlubricating system; or The method includes: 1) The pre-running lubricant is dropped or coated onto the surface of the amorphous carbon-based thin film aC / silicon nitride ceramic pair and run for 10 minutes under the conditions of a rotation speed of 31.4 mm / s and a Hertzian contact stress of 1.5 GPa; wherein the pre-running lubricant is composed of the following components by weight percentage: dipropyl sulfite 2%, diethyl sulfate 3%, glycerol 5%, ethylene glycol 30%, propylene glycol 10%, and triethylene glycol 50%; 2) After cleaning the surface of the amorphous carbon-based thin film aC / silicon nitride ceramic pair, an oil-based liquid is dropped onto the surface of the amorphous carbon-based thin film aC / silicon nitride ceramic pair. Friction is performed under the conditions of a rotation speed of 62.8 mm / s and a Hertzian contact stress of 87 MPa. In-situ superlubricity of the oil-based liquid can be achieved in the superlubricating system. The oil-based liquid is composed of the following components by weight percentage: 2% oleic acid, 20% methyl silicone oil, 50% PAO 2, and 28% PAO 4.

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