Method for preparing and testing binary environment-friendly water lubricant

Abstract

A preparation method of a binary environment-friendly water lubricant belongs to the technical field of lubricants, the binary environment-friendly water lubricant is prepared from boric acid, dicyandiamide, stearic acid and an ethanol-water mixed solution, and the preparation method of the binary environment-friendly water lubricant comprises two processes; according to the testing method of the binary environment-friendly water lubricant, a high-speed ring-block friction testing machine is selected as specific testing equipment, an experimental polymer material is a polymer material and a stainless steel metal ring, and the binary composite environment-friendly water lubricant is injected into a friction interface in a dropwise adding mode. The preparation process is simple and convenient, the production period is short, the influence and harm to the environment are small, no other components are added, the lubricant can be independently used, the friction coefficient is reduced, and when the binary composite environment-friendly water lubricant is prepared from boric acid, dicyandiamide and stearic acid (1: 1: 1) in a hydrothermal mode under the same condition, the wear resistance of a polyformaldehyde material can be improved by 91%, and the service life of the polyformaldehyde material is prolonged. And the wear resistance of related mechanisms and the service life of equipment are improved. The method has a good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of water lubricants, in particular to a preparation and testing method for a binary environmentally friendly water lubricant. Background Art

[0002] In a fluid lubrication system, the load-carrying capacity of the lubricating liquid film is directly proportional to the viscosity of the lubricating liquid and inversely proportional to the square of the film thickness. Water is a low-viscosity liquid. Therefore, it is not easy to form a water film when using water as a lubricant. Even under some harsh conditions, water lubrication hardly produces a fluid lubrication effect (please give an example), resulting in a low load-carrying capacity of water lubricated bearings, causing the water lubricated bearing bush and the journal running under non-fluid lubrication conditions to come into direct contact, resulting in serious wear and even bearing burning accidents. And an effective strategy to solve the above problems is to add an additive water lubricant with good transferability and film-forming performance to water. The addition of additives in water helps to form a lubricating protective film at the interface, avoiding the direct contact between the bearing bush and the journal, thereby fundamentally preventing the occurrence of vicious accidents such as biting and even bearing burning.

[0003] With the development of technology, the performance of water lubricants has also made great progress. For example, in the patent application with the Chinese patent number "201210027265.1" and the patent name "A graphene oxide-fullerene water-based lubricant", it solves technical problems such as high lubricant cost, poor stability, and low lubrication performance; in the patent application with the patent number "201410212428.2" and the patent name "Water-based graphene-molybdenum disulfide nanotube lubricant", after functionalizing graphene and molybdenum disulfide nanotubes to make them water-soluble respectively, they are then compounded in a certain proportion to obtain the finished product; in the patent application with the patent number "201510504476.3" and the patent name "Graphene oxide-polymer microsphere water-based lubricant", graphene oxide powder and polymer microsphere emulsion are mixed and ultrasonically oscillated to fully disperse the graphene oxide powder in the emulsion to obtain the finished product. The above-mentioned existing technologies, restricted by the materials used and the preparation processes, have disadvantages such as relatively poor stability, high cost, complex preparation processes, and difficulty in large-scale production. In the patent applications with the patent number "201610453233.6" and the patent name "A calcium stearate lubricant with low solid content for papermaking and its preparation method", and the patent number "201611138422.0" and the patent name "A boron-containing complex calcium sulfonate-based grease composition and its preparation method", the main component that plays a lubricating role in the former is calcium stearate obtained by reacting stearic acid with calcium hydroxide, and it is weakly alkaline after the reaction; the latter synthesizes a semi-solid grease using long carbon chain alkyl compounds and their substituted compounds as raw materials; the calcium stearate involved in the patent application of 201611138422.0 is weakly alkaline and cannot provide an acidic environment. At the same time, if alkaline calcium stearate is added to the raw material boric acid, it will chemically react with boric acid, affecting the formation of the key lubricating component boron nitride, thereby destroying the stable existence and lubricating and wear-resistant performance of the water lubricant.

[0004] For another example, in the patent applications with the Chinese patent number "201910073191.7" and the patent name "A preparation method of a water-soluble carbon nitride lubricant", and the patent number "201910073806.6" and the patent name "A preparation method of a water-soluble carbon nitride lubricant", since the patent application of "201910073191.7" has only one key component, namely water-soluble carbon nitride, it will cause problems of insufficient lubrication performance. In the patent application of "201910073806.6", there is a drawback that due to the secondary physical mixing of the lubricating component ionic liquid, the water-soluble carbon nitride has poor compatibility. Summary of the Invention

[0005] In order to overcome the drawbacks of existing water-based lubricants as described in the background art due to limitations in preparation materials and processes, the present invention provides a preparation method with a simple process, a significantly shortened production cycle, and the prepared finished product having excellent lubricating and wear-resistant properties, as well as characteristics such as being green and environmentally friendly, harmless to the human body, and capable of long-term stable preservation. It does not require the addition of any other components and can be used alone as a lubricant for equipment. During application, high-temperature hydrothermal conditions can promote the dissolution of stearic acid in water, provide an acidic environment, and promote the polymerization of boric acid and dicyandiamide to form stable boron nitride. The stearic acid dissolved in water can also play a lubricating role and reinforce the lubricating performance of water-soluble boron nitride. The three raw materials play different functions and cooperate synergistically with each other, showing excellent friction-reducing and wear-resistant properties when materials such as bearings, bushings, or gaskets made of polymer materials are in friction with a stainless steel metal shaft, improving the wear resistance of related mechanisms and the service life of equipment. A preparation and testing method for a binary environmentally friendly water lubricant.

[0006] The technical solution adopted by the present invention to solve its technical problems is as follows: A preparation method for a binary environmentally friendly water lubricant. The materials of the binary environmentally friendly water lubricant include boric acid, dicyandiamide, stearic acid, and an ethanol-water mixture. Among them, the amount of boric acid is 10 g - 20 g, the amount of dicyandiamide is 10 g - 20 g, and the amount of stearic acid is 90 g - 110 g. The ethanol ratio of the ethanol-water mixture is 40% - 60%. The preparation process of the binary environmentally friendly water lubricant is as follows: S1: Weigh boric acid, dicyandiamide, and stearic acid and disperse them in an ethanol-water mixture containing ethanol at room temperature. After fully stirring and dissolving, transfer them to a 150 mL hydrothermal reaction kettle with a polytetrafluoroethylene lining. S2: Tighten the lid of the hydrothermal reaction kettle for sealing and place it in an oven at a constant temperature for a certain period of time. After natural cooling, a binary composite green water lubricant of boron nitride and stearic acid is obtained. The testing method for the binary environmentally friendly water lubricant is as follows: Specifically, a high-speed ring-block friction testing machine is selected as the testing equipment. The experimental polymer material is one of polyetheretherketone, polyimide, polyphenylene sulfide, and polyoxymethylene engineering plastic raw materials. The metal ring used for the friction experiment with the engineering plastic raw material is made of stainless steel, and its surface roughness is 0.1 - 0.8 μm. The testing conditions for the influence of the binary environmentally friendly water lubricant on the tribological properties of the above-mentioned mating pairs are: load 50 N, rotation speed 0.5 m / s, testing time 1 h. The binary composite environmentally friendly water lubricant is injected into the friction interface by the method of dropping one by one, and the dropping rate is 2 mL / h.

[0007] Furthermore, in the preparation method of the binary environmentally friendly water lubricant, the temperature of the ethanol-water mixture is between 20°C and 30°C, preferably 25°C.

[0008] Further, in the preparation method of the binary environmentally friendly water lubricant, the mass mixing ratio of boric acid, dicyandiamide and stearic acid white solid is 1:1:1 to 1:1:5.

[0009] Further, in the preparation method of the binary environmentally friendly water lubricant, the prepared binary composite green water lubricant of boron nitride and stearic acid has a mass ratio of boron nitride to stearic acid between 1:1 and 1:3.

[0010] Further, in the preparation method of the binary environmentally friendly water lubricant, the oven temperature during hydrothermal treatment is 150-250 °C, and the hydrothermal time is 1-3 hours.

[0011] Further, in the preparation method of the binary environmentally friendly water lubricant, boric acid and dicyandiamide respectively provide boron element and nitrogen element for the synthesis of boron nitride. After high temperature in the hydrothermal autoclave, the high pressure in the autoclave promotes the reaction between boron nitride and dicyandiamide to in-situ generate water-soluble boron nitride. Boron nitride has good lubricating and anti-wear properties. The high-temperature hydrothermal conditions adopted can improve the solubility of stearic acid in water and promote its in-situ composite with the hydrothermally generated boron nitride, thus creating a binary environmentally friendly water lubricant with an organic combination of boron nitride and stearic acid. At the same time, due to the high thermal stability of stearic acid, high-temperature hydrothermal treatment will not damage its structure and properties and can still maintain its good physical and chemical properties, and good lubricating performance can be exerted in terminal applications.

[0012] Further, in the test of the binary environmentally friendly water lubricant, the water lubricant is dripped drop by drop into the running friction pair in a line-plane or plane-plane contact manner, which can better simulate the working conditions of the workpiece and achieve a better detection purpose.

[0013] The beneficial effects of the present invention compared with the prior art are as follows: The present invention has the remarkable advantages of simple preparation process and short production cycle; since it does not contain metal components, it has little impact and harm on the environment, reflecting the characteristics of green environmental protection; it has remarkable dispersibility and stability and can be stably stored for a long time. The present invention is used as a cutting fluid in industrial production (especially in the processes of punch drawing, punching, blanking, bending, etc. during the workpiece forming process), and in the fields such as lubrication of medical and health care instruments. Due to its excellent lubrication and wear resistance performance, green environmental protection, and harmlessness to the human body, etc., the present invention does not need to add any other components and can be used alone; during application, when the parts such as bearings, bushings or gaskets made of polymer materials are in friction with a stainless steel shaft, it can show excellent anti-friction and wear resistance performance. Compared with using pure water as a lubricant, the present invention prepared by hydrothermal method with boric acid:dicyandiamide:stearic acid (1:1:3) has a significant improvement effect on the tribological performance of the polyoxymethylene-stainless steel shaft pair, and the friction coefficient can be reduced from 0.38 to 0.22. Under the same conditions, when using the binary composite environmentally friendly water lubricant prepared by hydrothermal method with boric acid:dicyandiamide:stearic acid (1:1:1), the wear resistance (i.e., service life) of the polyoxymethylene material can be increased by 91%, improving the wear resistance of the relevant mechanism and the service life of the equipment. In summary, the present invention has a good application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram showing that the binary composite environmentally friendly water lubricant prepared by the present invention has excellent dispersibility and stability.

[0015] Figure 2 It is a schematic diagram showing that the binary composite green water lubricant prepared by the present invention presents an obvious Tyndall effect (proving a colloidal stable state). DETAILED DESCRIPTION OF THE INVENTION

[0016] A preparation method of a binary environmentally friendly water lubricant. The materials of the binary environmentally friendly water lubricant include boric acid, dicyandiamide, stearic acid and an ethanol-water mixture. Example 1: Weigh 20 g of boric acid, 20 g of dicyandiamide and 20 g of stearic acid. The white solids are dispersed in 100 g of an ethanol-water mixture containing 50% ethanol at room temperature (about 25 °C); after fully stirring and dissolving, it is transferred to a 150 mL hydrothermal reactor with a polytetrafluoroethylene liner and placed in an oven at 150 °C for 3 h of heat preservation; after natural cooling, a binary composite green water lubricant with a mass ratio of boron nitride:stearic acid = 1:1 is obtained. Example 2: Weigh 15 g of boric acid, 15 g of dicyandiamide and 30 g of stearic acid. The white solids are dispersed in 100 g of an ethanol-water mixture containing 50% ethanol at room temperature (about 25 °C); after fully stirring and dissolving, it is transferred to a 150 mL hydrothermal reactor with a polytetrafluoroethylene liner and placed in an oven at 200 °C for 2 h of heat preservation; after natural cooling, a binary composite green water lubricant with a mass ratio of boron nitride:stearic acid = 1:2 is obtained. Example 3: Weigh 10 g of boric acid, 10 g of dicyandiamide and 30 g of stearic acid. The white solids are dispersed in 100 g of an ethanol-water mixture containing 50% ethanol at room temperature (about 25 °C); after fully stirring and dissolving, it is transferred to a 150 mL hydrothermal reactor with a polytetrafluoroethylene liner and placed in an oven at 250 °C for 1 h. After natural cooling, a binary composite green water lubricant with a mass ratio of boron nitride:stearic acid = 1:3 is obtained. For the finished product prepared by the present invention, among them, boric acid and dicyandiamide respectively provide boron element and nitrogen element for the synthesis of boron nitride. After high temperature in the hydrothermal reactor, the high pressure in the reactor promotes the reaction between boron nitride and dicyandiamide to in-situ generate water-soluble boron nitride, and boron nitride has good lubrication and anti-wear properties. This is one of the important components of the water-based lubricant of the present invention. The high-temperature hydrothermal conditions adopted by the present invention can improve the solubility of stearic acid in water, promote its in-situ composite with the boron nitride generated by hydrothermal reaction, thereby creating a binary environmentally friendly water lubricant in which boron nitride and stearic acid are organically combined. At the same time, due to the high thermal stability of stearic acid, high-temperature hydrothermal treatment will not damage its structure and properties, and it can still maintain its good physical and chemical properties.

[0017] Specifically, the present invention has the following advantages: (1) From the comparison of the preparation process of the water lubricant, it can be seen that the water lubricant involved in the present invention has the remarkable advantages of simple preparation process and short production cycle. (2) In the binary composite environmentally friendly water lubricant prepared by the present invention, there is no metal component, and the impact and harm to the environment are small, reflecting the characteristics of green environmental protection. (3) The binary composite environmentally friendly water lubricant prepared by the present invention has excellent dispersibility and stability (see attached Figure 1 , specifically, the binary composite green water lubricant prepared by the present invention shows an obvious Tyndall effect (proving a colloidal stable state); from Figure 1 、 2(Examples 1-3) It can be seen that as the content of boron nitride in the colloid decreases, the Tyndall effect becomes less and less obvious; this indicates that the particle size range in the colloid is below 100 nm and is mainly composed of hydrothermally synthesized boron nitride particles, which can be stably stored for a long time). 4) The binary composite environmentally friendly water lubricant prepared by the present invention exhibits excellent anti-friction and wear-resistant properties when rubbing against a stainless steel shaft for parts such as bearings, bushings, or gaskets made of polymer materials. Compared with using pure water as the lubricant, the binary composite environmentally friendly water lubricant hydrothermally prepared with boric acid:dicyandiamide:stearic acid (1:1:3) has a significant improvement in the tribological properties of the polyoxymethylene-stainless steel shaft pair, and the friction coefficient can be reduced from 0.38 to 0.22. Under the same conditions, when using the binary composite environmentally friendly water lubricant hydrothermally prepared with boric acid:dicyandiamide:stearic acid (1:1:1), the wear resistance (i.e., service life) of the polyoxymethylene material can be increased by 91% (see attached Figure 2 , attached Figure 2 is a schematic diagram of the friction coefficient (a) and wear amount (b) during the rubbing of the polyoxymethylene-stainless steel shaft pair, and Examples 1-3 are respectively compared with pure water as the water lubricant; Note: Lubricant 0 is deionized water used as the water lubricant in the comparative example, and Lubricants 1-3 are Examples 1-3 used as the water lubricant respectively; From attached Figure 2 a, it can be seen that as the content of hydrothermally synthesized boron nitride particles in the binary composite water lubricant decreases, the lubricating performance of this binary composite water lubricant for the polyoxymethylene-stainless steel pair gradually improves, indicating that the substance playing a lubricating role in the binary composite system is mainly stearic acid; From attached Figure 2 b, it can be seen that as the content of hydrothermally synthesized boron nitride particles in the binary composite water lubricant decreases, in the presence of this binary composite water lubricant, the wear rate of polyoxymethylene and stainless steel during rubbing gradually increases, indicating that the substance playing an anti-wear role in the binary composite system is mainly hydrothermally synthesized boron nitride particles).

[0018] Compared with the patent applications with patent numbers 201210027265.1, 201410212428.2, and 201510504476.3, the present invention directly mixes three raw materials (boric acid, dicyandiamide, and stearic acid) in a certain proportion by using the high-temperature hydrothermal method, and in-situ hydrothermally prepares a composite water lubricant that can stably maintain a colloidal state in water for a long time. The binary environmentally friendly water lubricant prepared by this method has the advantages of wide raw material sources, low cost, simple preparation process, and easy large-scale production. In addition, compared with the patent applications with patent numbers 201610453233.6 and 201611138422.0, the main component that plays a lubricating role in the former is calcium stearate obtained by reacting stearic acid with calcium hydroxide, and it is weakly alkaline after the reaction; the latter synthesizes a semi-solid lubricating grease from long-chain alkyl compounds and their substituted compounds. The above comparative technologies are significantly different from the present invention. Specifically, first, the present invention directly uses stearic acid as one of the main lubricating components, which is different from the patent application of 201610453233.6. The calcium stearate involved in this invention is weakly alkaline and cannot provide an acidic environment like stearic acid. At the same time, the alkaline calcium stearate will chemically react with another raw material boric acid in the present invention, affecting the formation of the key lubricating component boron nitride, thereby destroying the stable existence and lubricating and wear-resistant performance of the water lubricant of the present invention. In addition, the colorless and transparent water-based lubricant in the present invention is significantly different from the viscous liquid or semi-solid lubricating grease created by the above two technologies in terms of properties and appearance, so it determines that there are also significant differences in the application fields. Therefore, the present invention has significant innovation. In addition, the present invention is also significantly different from the patent applications of 201910073191.7 and 201910073806.6. Specifically, first, the present invention has created a binary composite system, fundamentally avoiding the problem of insufficient lubricating performance caused by only one key component, i.e., water-soluble carbon nitride, in the patent application of 201910073191.7. The two key components in the binary composite system of the present invention play lubricating and anti-wear roles respectively. Therefore, the present invention has significant innovation in the lubricant creation strategy compared with the above patents. In addition, this binary composite system adopts a one-step method and in-situ synthesis, ensuring excellent compatibility of the lubricating and wear-resistant components, which is essentially different from the disadvantages of the secondary physical mixing of the lubricating component ionic liquid in the patent application of 201910073806.6 and its poor compatibility with water-soluble carbon nitride. Therefore, the present invention has significant innovation in the lubricant functional composite design compared with the above patents.

[0019] Testing method for binary environmental protection water lubricant. Specifically, a high-speed ring-block friction testing machine is selected as the testing equipment. The polymer materials for the experiment are one of the engineering plastic raw materials such as polyetheretherketone, polyimide, polyphenylene sulfide, and polyoxymethylene. The metal ring for the counter friction experiment with the engineering plastic raw material is made of stainless steel (S30408, GB / T 3280-2015), and its surface roughness is 0.1-0.8 μm. The testing conditions for the influence of this water lubricant on the tribological properties of the above-mentioned mating pairs are: load 50 N, rotational speed 0.5 m / s, testing time 1 h. The binary composite environmental protection water lubricant is injected into the friction interface in a drop-by-drop manner, and the dropping rate is 2 mL / h. Compared with the prior art, a calcium stearate lubricant with low solid content for papermaking and its preparation method (201610453233.6) and a boron-containing complex calcium sulfonate-based grease composition and its preparation method (201611138422.0), the practicality of the lubrication performance test of the relevant lubricants is not involved and considered. However, the present invention details an evaluation method for the lubrication and anti-wear performance of the water lubricant that conforms to the actual operating conditions for specific use scenarios, significantly improving the practicability and practical application value of the present invention.

[0020] In summary, the present invention has the remarkable advantages of simple preparation process and short production cycle; since it does not contain metal components, it has little impact and harm on the environment, reflecting the characteristics of green environmental protection; it has remarkable dispersibility and stability and can be stably stored for a long time. The present invention is used as a cutting fluid in industrial production (especially in the processes of punch drawing, punching, blanking, bending, etc. during the workpiece forming process), as well as in the field of lubrication of medical and health care instruments. Due to its excellent lubrication and wear resistance, green environmental protection, and harmlessness to the human body, etc., the present invention does not need to add any other components and can be used alone; during application, it can exhibit excellent friction reduction and wear resistance when the parts such as bearings, bushings or gaskets made of polymer materials are in counter friction with stainless steel shafts. Compared with using pure water as the lubricant, the present invention prepared by hydrothermal method with boric acid:dicyandiamide:stearic acid (1:1:3) has a significant improvement effect on the tribological properties of the polyoxymethylene-stainless steel shaft mating pair, and the friction coefficient can be reduced from 0.38 to 0.22. Under the same conditions, when using the binary composite environmental protection water lubricant prepared by hydrothermal method with boric acid:dicyandiamide:stearic acid (1:1:1), the wear resistance (i.e., service life) of the polyoxymethylene material can be increased by 91%, improving the wear resistance of the relevant mechanisms and the service life of the equipment.

[0021] The foregoing has shown and described the basic principles, main features and advantages of the present invention. For a person skilled in the art, it is obvious that the present invention is limited to the details of the above-described exemplary embodiments, and that without departing from the spirit or essential characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, in whatever aspect, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes that fall within the meaning and scope of the equivalent elements of the claims in the present invention.

[0022] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. A person skilled in the art should regard the specification as a whole. The technical solutions in the embodiments can also be appropriately combined to form other embodiments that can be understood by a person skilled in the art.

Claims

1. A method for preparing a binary environmentally friendly water lubricant, characterized in that: The materials of the binary environmentally friendly water lubricant include boric acid, dicyandiamide, stearic acid and ethanol-water mixture, wherein the amount of boric acid is 10 g ~ 20g, the amount of dicyandiamide is 10g ~ 20g, the amount of stearic acid is 90g ~ 110g, and the ethanol ratio of the ethanol-water mixture is 40% ~ 60%; the preparation process of the binary environmentally friendly water lubricant is as follows, S1: weigh boric acid, dicyandiamide and stearic acid and disperse them in an ethanol-water mixture containing ethanol at room temperature, stir and dissolve them thoroughly, and then transfer them to a 150mL hydrothermal reactor with a polytetrafluoroethylene lining; S2: tighten the lid of the hydrothermal reactor and seal it, place it in a constant temperature oven for a certain period of time, and obtain a binary composite green water lubricant of boron nitride and stearic acid after natural cooling; the test method of the binary environmentally friendly water lubricant is as follows The specific test equipment is a high-speed ring-block friction tester. The polymer material of the experiment is one of polyetheretherketone, polyimide, polyphenylene sulfide, and polyoxymethylene engineering plastic raw materials. The metal ring used in the friction experiment with the engineering plastic raw material is a stainless steel metal ring with a surface roughness of 0.1-0.8μm. The test conditions for the influence of binary environmentally friendly water lubricant on the tribological properties of the above-mentioned pair are: load 50N, rotation speed 0.5m / s, test time 1h, and the binary composite environmentally friendly water lubricant is injected into the friction interface drop by drop at a dripping rate of 2mL / h.

2. The method for preparing a binary environmentally friendly water lubricant according to claim 1, characterized in that: In the preparation method of the binary environmentally friendly water lubricant, the temperature of the ethanol-water mixture is between 20°C and 30°C, preferably 25°C.

3. The method for preparing a binary environmentally friendly water lubricant according to claim 1, characterized in that: In the preparation method of the binary environmentally friendly water lubricant, the mass mixing ratio of boric acid, dicyandiamide and stearic acid white solid is 1:1:1~1:1:

5.

4. The method for preparing a binary environmentally friendly water lubricant according to claim 1, characterized in that: In the preparation method of the binary environmentally friendly water lubricant, the prepared binary composite green water lubricant of boron nitride and stearic acid has a mass ratio of boron nitride to stearic acid of 1:1 to 1:

3.

5. The method for preparing a binary environmentally friendly water lubricant according to claim 1, characterized in that: In the preparation method of the binary environmentally friendly water lubricant, the oven temperature during the hydrothermal treatment is 150-250° C., and the hydrothermal time is 1-3 hours.

6. The method for preparing a binary environmentally friendly water lubricant according to claim 1, characterized in that: In the preparation method of the binary environmentally friendly water lubricant, boric acid and dicyandiamide provide boron and nitrogen elements respectively for the synthesis of boron nitride. After being subjected to high temperature in a hydrothermal kettle, the high pressure in the kettle promotes the reaction between boron nitride and dicyandiamide to generate water-soluble boron nitride in situ, and boron nitride has good lubrication and anti-wear properties. The high-temperature hydrothermal conditions adopted can improve the solubility of stearic acid in water, promote its in-situ recombination with the hydrothermally generated boron nitride, thereby creating a binary environmentally friendly water lubricant organically combining boron nitride and stearic acid. At the same time, due to the high thermal stability of stearic acid, high-temperature hydrothermal treatment will not damage its structure and performance, and it can still maintain its good physical and chemical properties. In terminal applications, it can exert good lubrication properties.

7. The test method of binary environmentally friendly water lubricant according to claim 1, characterized in that: In the test of binary environmentally friendly water lubricant, the water lubricant is dripped drop by drop between the running friction pairs in a line-surface or surface-to-surface contact manner, which can better simulate the operating conditions of the workpiece and achieve better detection purposes.

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