Adhesive, wide temperature range high temperature lubricating coating and method of making, coating and method of coating

Abstract

The application provides a binder, a wide-temperature-range high-temperature lubricating coating and a preparation method, a coating and a coating method thereof. The preparation method of the wide-temperature-range high-temperature lubricating coating comprises the following steps: proportionally adding aminated boron nitride, low-melting-point glass powder, aluminum pigment and anti-wear pigment filler into a crushing device, adding water, crushing and grinding for 12-48 hours to obtain a slurry; adding an aqueous phase dispersion solution of the binder into the slurry, adding water, stirring and mixing, and pre-mixing the coating; and stirring and dispersing the pre-mixed coating to obtain a finished wide-temperature-range high-temperature lubricating coating. The coating adopts boron oxide and fumed silica modified inorganic phosphate resin as the binder, aminated modified hexagonal boron nitride as the main lubricating and anticorrosive filler, low-melting-point glass powder and aluminum pigment as the anticorrosive toughening agent, and other functional fillers and additives, and the coating obtained through high-temperature curing can be used in a wide-temperature-range and has a lower wear rate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coating corrosion protection, in particular to a binder, a wide-temperature-range high-temperature lubricating coating and a preparation method thereof, a coating and a coating method. BACKGROUND

[0002] Due to the high humidity and high salt environment of the marine atmospheric environment, the moving parts of the parts of the aero-engine and gas turbine, such as fasteners, bearings and the like, work in a strong coupling condition of wear-corrosion, which can easily accelerate the damage of the metal matrix. Once failed, it will affect the working efficiency and reliability of the power equipment, or even cause safety accidents. The lubrication and corrosion protection of the surface is very important.

[0003] However, the working temperature of the moving parts of the fasteners and bearings of the power equipment is as high as 600-800℃. At this temperature stage, the lubricating grease and the conventional organic solid lubricating adhesive coating have already failed. In addition, there is a large temperature fluctuation in the working process of the power equipment. The protective coating must develop towards a wide temperature range, a higher temperature, a lower overall friction coefficient and a lower wear rate. However, the current domestic high-temperature lubricating coating cannot be used universally. The friction coefficient is low only in a part of the temperature range, the friction coefficient is greater than 0.2 and the wear rate is high in other temperature ranges, and the corrosion resistance of the coating is also poor. Compared with similar foreign products, there is still a big gap. It is of great significance to research and develop a wide-temperature-range high-temperature lubricating and corrosion-resistant coating. SUMMARY

[0004] The present application provides a binder, a wide-temperature-range high-temperature lubricating coating and a preparation method thereof, a coating and a coating method, to solve the problem that the existing power equipment coating has a high wear rate under high temperature conditions and is difficult to adapt to a wide temperature range.

[0005] In a first aspect, the present application provides a preparation method of a binder, comprising the following steps:

[0006] Add chromium trioxide to the aqueous phosphoric acid solution, stir and dissolve, heat to 80-85℃, add aluminum hydroxide to the solution, heat to 100-140℃ after complete dissolution and keep for 1-3h to obtain a chromium aluminum phosphate binder;

[0007] Add fumed silica and boron oxide to the chromium aluminum phosphate binder, keep for 1-3h, and then naturally cool to room temperature to obtain a modified binder.

[0008] The method for preparing a wide-temperature-range high-temperature lubricating coating of the present application is carried out at room temperature, so it has the characteristics of mild reaction conditions and easy control.

[0009] And in the method of the present application, the aminated boron nitride, low-melting-point glass powder, aluminum pigment and anti-wear pigment filler are ground and dispersed. The binder has a cross-linked network structure in microcosm, and therefore the addition of the binder provides a good accommodation space for the nano-complexes. After stirring and dispersion, the nano-complexes formed by the above materials are uniformly distributed in the network structure provided by the binder, and after solidification, a uniform and dense protective coating is formed on the surface of the substrate, thereby exerting the anti-wear and lubricating characteristics of each component.

[0010] In a second aspect, the present application provides a binder prepared by the preparation method of the binder according to any one of the first aspect.

[0011] In a third aspect, the present application provides a preparation method of a wide-temperature-range high-temperature lubricating coating, comprising the following steps:

[0012] The aminated boron nitride, low-melting-point glass powder, aluminum pigment and anti-wear pigment filler are proportionally introduced into a crushing device, water is added, and crushing and grinding are carried out for 12-48 h to obtain a slurry;

[0013] The water phase dispersion liquid of the binder provided in the second aspect is added to the slurry, water is further added, and the pre-mixed coating is obtained by stirring and mixing;

[0014] The pre-mixed coating is stirred and dispersed to obtain a finished wide-temperature-range high-temperature lubricating coating.

[0015] Optionally, the aminated boron nitride is prepared as follows:

[0016] The boron nitride powder, urea and deionized water are introduced into a ball milling device, and ball milling crushing is carried out at a speed of 400-600 rpm for 24-72 h to obtain a crushed slurry;

[0017] The crushed slurry is suction filtered, the filter cake is washed with deionized water until the filtrate is neutral, and the aminated boron nitride powder is obtained after drying;

[0018] The mass ratio of boron nitride, urea and water is 1-5:30-60:20-40.

[0019] Optionally, the water phase dispersion liquid of the binder is added in an amount of 25-35 parts by weight, the aminated boron nitride is added in an amount of 5-15 parts by weight, the low-melting-point glass powder is added in an amount of 3-5 parts by weight, the aluminum pigment is added in an amount of 3-5 parts by weight, the anti-wear pigment filler is added in an amount of 10-20 parts, and the water is added in an amount of 20-60 parts.

[0020] Optionally, the solid content in the water phase dispersion liquid of the binder is 60-65 wt%.

[0021] During the stirring and dispersion process, the stirring rate is 2000-5000 rpm, and the dispersion time is 10-20 min.

[0022] In a fourth aspect, the present application provides a wide-temperature-range high-temperature lubricating coating prepared by the method for preparing a wide-temperature-range high-temperature lubricating coating according to any one of the third aspect.

[0023] The wide-temperature-range high-temperature lubricating coating of the present application has the following advantages:

[0024] 1) The micro-inorganic substances in the coating do not release organic gas during use, thus avoiding the pollution of volatile organic compounds to the environment.

[0025] 2) The boron hexaazide in the coating has a two-dimensional sheet structure, a large specific surface area, and stable chemical properties, and is dispersed in the coating to effectively shield the corrosion medium, so that the coating has excellent corrosion resistance.

[0026] 3) The low-melting-point glass powder and aluminum pigment are used as the corrosion-resistant toughening agent, the low-melting-point glass powder melts and penetrates and seals the fine pores of the coating at high temperature, thereby enhancing the corrosion resistance and oxidation resistance of the coating, and forming a glaze lubricating layer on the surface of the coating through the “sweating” effect, thereby improving the high-temperature lubricating capacity of the coating, and the aluminum pigment can provide cathodic protection for the matrix, thereby further improving the corrosion resistance of the coating.

[0027] In a fifth aspect, the present application provides a coating method, comprising the following steps:

[0028] The wide-temperature-range high-temperature lubricating coating provided in the fourth aspect is uniformly applied to the surface of a substrate, and is left to dry for 1-18 h to form a pre-coating layer on the surface of the substrate;

[0029] The substrate with the pre-coating layer attached to the surface is placed in a heating device, and is heated and cured in an air atmosphere to form a coating layer on the surface of the substrate;

[0030] During the heating and curing process, the temperature is first increased from room temperature to 120-150°C at a rate of 2-3°C / min, and is kept at this temperature for 1-1.5 h; then the temperature is increased to 305-315°C at a rate of 1-2°C / min, and is kept at this temperature for 1-1.5 h, and is then naturally cooled;

[0031] The thickness of the cured coating layer is 15-30 μm.

[0032] The coating method of the present application, in combination with the use of the wide-temperature-range high-temperature lubricating coating described above, can provide a high-strength coating layer with strong adhesion, impact resistance, heat resistance, thermal shock resistance, wide temperature range adaptation, corrosion resistance, wear resistance, and high-temperature lubrication.

[0033] In a sixth aspect, the present application provides a coating layer prepared by the coating method provided in the fifth aspect, and the thickness of the coating layer is 15-30 μm. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0035] Figure 1 The test results of the coating adhesion of the coating of the present application example 1 and example 2 after oxidation test;

[0036] Figure 2 The outer tube comparison chart of the coating of the present application example 1 and example 2 before and after thermal shock test;

[0037] Figure 3 The friction coefficient curve chart of the coating of the present application example 1 and example 2 before and after high temperature oxidation at 800℃ for 12h;

[0038] Figure 4 The XRD pattern of unmodified chromium aluminum phosphate binder at different temperatures;

[0039] Figure 5 The XRD pattern of modified chromium aluminum phosphate binder at different temperatures. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are some embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort also belong to the scope of protection of the present application.

[0041] In the first aspect, the present application provides a preparation method of a binder, comprising the following steps:

[0042] Add chromium trioxide to the aqueous phosphoric acid solution, stir to dissolve, and heat to 80-85℃ to obtain an acidic solution;

[0043] Add aluminum hydroxide to the acidic solution, heat to 100-140℃ after complete dissolution, and keep for 1-3h to obtain a precursor solution;

[0044] Add fumed silica and boron oxide to the precursor solution, keep for 1-3h, and then naturally cool to room temperature to obtain the binder.

[0045] In the present application, the precursor solution is also the unmodified chromium aluminum phosphate binder, and the "binder" referred to in the present application is the modified chromium aluminum phosphate binder.

[0046] In the present application, the binder uses acid chromium aluminum phosphate salt, and the aforementioned phosphate is modified by boron oxide and fumed silica: the addition of boron oxide can introduce reversible B-O-P and B-O-B covalent bonds in the P-O-P network, increase the amorphous content of the resin, enhance the toughness of the phosphate resin, and reduce the thermal stress caused by phase change; the low melting point of boron oxide also gives the resin the ability to repair small thermal stress cracks during thermal cycling, greatly improving the high temperature resistance and thermal shock resistance of the coating.

[0047] The large specific surface area and abundant surface silicon hydroxyl groups of fumed silica make it extremely easy to adsorb on the surface of the lubricant, preventing oxygen atoms from contacting, improving the high temperature oxidation resistance of the lubricant, and at the same time improving the dispersibility and interfacial bonding of the lubricant in the resin, reducing the porosity of the coating and improving the coating density; the fumed silica nanoparticles attached to the surface of the lubricant act as "micro bearings" to reduce the friction coefficient, while repairing the friction surface, greatly improving the friction and wear resistance of the coating.

[0048] The preparation method of the binder of the present application uses acid chromium aluminum phosphate salt as the main material and is supplemented with fumed silica and boron oxide. The above materials are reacted at 100-140℃ to introduce reversible B-O-P and B-O-B covalent bonds in the P-O-P network of the acid chromium aluminum phosphate salt, increase the amorphous content of the resin, enhance the toughness of the phosphate resin, and at the same time give the coating high temperature resistance and thermal shock resistance. The addition of fumed silica can improve the friction and wear resistance of the coating. The preparation method of the binder of the present application has the characteristics of short steps, easy operation, easy implementation and time saving.

[0049] In a second aspect, the present application provides a binder prepared by the preparation method of the binder of any one of the above first aspect.

[0050] The binder provided by the present application has the beneficial effects as described in the preparation method of the binder of the first aspect, which will not be repeated here.

[0051] In a third aspect, the present application provides a preparation method of a wide temperature range high temperature lubricating coating, comprising the following steps:

[0052] Proportionally add amino boron nitride, low melting point glass powder, aluminum pigment and anti-wear pigment filler into a crushing device, add water, and crush and grind for 12-48h to obtain a slurry;

[0053] Add the aqueous dispersion of the binder provided by the above second aspect to the slurry, and then add water, stir and mix to obtain a premixed coating;

[0054] Disperse the premixed coating by stirring to obtain a finished wide temperature range high temperature lubricating coating.

[0055] In the present application, the aqueous dispersion of the binder is a suspension formed by mixing the binder with water.

[0056] The crushing device of the present application is a ball mill device, and the rotation speed is adjusted to 400-600 rpm during ball milling.

[0057] The aminated boron nitride is white powder with a particle size of 3-5 μm; the low-melting-point glass powder is white powder with a particle size of ≤10 μm; the aluminum pigment is silvery gray powder with a particle size of ≤10 μm; and the anti-wear pigment is one or more of alumina, silica, chrome green, titanium white, cobalt black, copper-chromium black, etc., with a particle size of ≤10 μm.

[0058] The hexagonal boron nitride is used as the main lubricating and corrosion-preventing agent. The hexagonal boron nitride has a low friction coefficient and excellent high-temperature resistance, and is a good high-temperature lubricating filler. Moreover, the hexagonal boron nitride has a two-dimensional sheet structure, a large specific surface area, and stable chemical properties, etc. When dispersed in the coating, it can effectively shield the corrosion medium and improve the corrosion resistance of the coating.

[0059] The low-melting-point glass powder and the aluminum pigment are used as the corrosion-preventing and toughening agent. The low-melting-point glass powder, which melts at high temperature, penetrates and seals the fine pores of the coating, thereby enhancing the corrosion resistance and oxidation resistance of the coating. Meanwhile, the low-melting-point glass powder forms a glaze lubricating layer on the surface of the coating through the "sweating" effect, thereby improving the high-temperature lubricating capacity of the coating. The aluminum pigment (including aluminum powder) can provide cathodic protection for the substrate, thereby further improving the corrosion resistance of the coating.

[0060] Through the synergistic cooperation of the binder, the lubricating and corrosion-preventing agent, and the corrosion-preventing and toughening agent, the coating can be used in a wide temperature range of room temperature to 800℃, has a friction coefficient of less than 0.2, a wear rate of less than 10 -5 m 3 / Nm, and has a salt spray resistance of more than 500 h.

[0061] The method for preparing the high-temperature lubricating coating of the present application is carried out at room temperature, and thus has the characteristics of mild reaction conditions and easy control.

[0062] In the method of the present application, the aminated boron nitride, the low-melting-point glass powder, the aluminum pigment, and the anti-wear pigment are ground and crushed. Long-time ball milling not only improves the compatibility between the materials, but also, at the micro level, refines the crystal grains of the materials, so that they are more likely to form nanocomposites through intermolecular forces. The binder has a crosslinked network structure at the micro level, and thus the addition of the binder provides a good accommodation space for the nanocomposites. After stirring and dispersion, the nanocomposites formed by the above-mentioned materials are uniformly distributed in the network structure provided by the binder, and can form a uniform and dense protective coating on the surface of the substrate after solidification, thereby exerting the characteristics of each component.

[0063] Optionally, the aminated boron nitride is prepared as follows:

[0064] The boron nitride powder, urea and deionized water are added into a ball milling device, and ball milling is performed at a rotating speed of 400-600 rpm for 24-72 h to obtain a broken slurry;

[0065] The broken slurry is suction filtered, the filter cake is washed with deionized water until the filtrate is neutral, and then dried to obtain the aminated boron nitride powder;

[0066] The mass ratio of the boron nitride, urea and water is 1-5:30-60:20-40.

[0067] In the present application, the amination of the boron nitride is achieved by using urea as the ammonia source and through long-time ball milling. In the ball milling process, the ball milling can refine the boron nitride powder grains and distort the crystal lattice, which is beneficial to the formation of the boron nitride-urea nanoscale composite structure. In addition, under the condition of high-speed ball milling, the urea is decomposed and deaminated to dissociate N-containing groups (-NH2), thereby achieving the amination of the boron nitride.

[0068] Optionally, the water-based dispersion of the binder is added in an amount of 25-35 parts by weight, the aminated boron nitride is added in an amount of 5-15 parts by weight, the low-melting-point glass powder is added in an amount of 3-5 parts by weight, the aluminum pigment is added in an amount of 3-5 parts by weight, the anti-wear pigment filler is added in an amount of 10-20 parts by weight, and the water is added in an amount of 20-60 parts by weight.

[0069] Optionally, the solid content in the water-based dispersion of the binder is 60-65 wt%.

[0070] During the stirring and dispersing process, the stirring speed is 2000-5000 rpm, and the dispersing time is 10-20 min.

[0071] In the present application, the stirring and dispersing is a process of mixing and fusing the substances in the premixed coating. In the present application, a high-speed disperser is used for dispersing. Only under the condition of the above-mentioned rotating speed of 2000-5000 rpm, the strong shearing force can make the components in the premixed coating more uniformly mixed, and the compatibility of the components is improved.

[0072] In a fourth aspect, the present application provides a wide-temperature-range high-temperature lubricating coating prepared by the preparation method of the wide-temperature-range high-temperature lubricating coating according to any one of the above-mentioned third aspect.

[0073] The wide-temperature-range high-temperature lubricating coating of the present application has the following advantages:

[0074] 1) The components in the coating are micro-inorganic substances, which will not release organic gas during use, so that the escape of volatile organic compounds can be avoided to pollute the environment.

[0075] 2) The boron hexaazide in the paint has the characteristics of two-dimensional sheet structure, large specific surface area, stable chemical properties, etc. When dispersed in the coating, it can effectively shield the corrosion medium, so that the paint has excellent corrosion resistance.

[0076] 3) The low-melting glass powder and aluminum pigment are used as anti-corrosion and toughening agents. The low-melting glass powder melts at high temperature and penetrates and seals the fine pores of the coating, thereby enhancing the anti-corrosion and oxidation resistance of the coating. At the same time, the glaze lubricating layer is formed on the surface of the coating through the "sweating" effect, thereby improving the high-temperature lubricating ability of the coating. The aluminum pigment can provide cathodic protection for the matrix, thereby further improving the corrosion resistance of the coating.

[0077] In a fifth aspect, the application provides a coating method, comprising the following steps:

[0078] The wide-temperature-range high-temperature lubricating paint provided in the fourth aspect is uniformly coated on the surface of the substrate, and is left to dry for 1-18 hours to form a pre-coating layer on the surface of the substrate.

[0079] The substrate with the pre-coating layer attached to the surface is placed in a heating device and heated and cured in an air atmosphere to form a coating layer on the surface of the substrate.

[0080] During the heating and curing process, the temperature is first increased from room temperature to 120-150°C at a rate of 2-3°C / min, and is kept at this temperature for 1-1.5 hours. Then the temperature is increased to 305-315°C at a rate of 1-2°C / min, and is kept at this temperature for 1-1.5 hours, and then is naturally cooled.

[0081] The thickness of the cured coating layer is 15-30 μm.

[0082] In the coating method of the application, the drying of the coating layer can reduce the occurrence of adverse consequences such as cracking and damage of the coating layer during the later heating and curing process.

[0083] In the application, the heating and curing process is not only a process of drying to remove water molecules in the coating layer, but also a process in which the components in the paint react. The binder in the paint is not only a carrier for the remaining components, but also a key adhesion agent. During the heating and curing process, the water in the paint coated on the surface of the substrate is gradually evaporated at a temperature of 120-150°C, leaving the materials in the paint except water. As the curing temperature gradually increases to 305-315°C, a network structure of the binder is formed in the curing process at this temperature, and reversible B-O-P and B-O-B covalent bonds are introduced into the P-O-P network, thereby increasing the amorphous phase content of the resin and enhancing the toughness of the phosphate resin, so as to provide a high-strength coating layer with impact resistance, heat resistance, thermal shock resistance, wide temperature range adaptation, corrosion resistance, wear resistance, and self-lubrication.

[0084] And in the high temperature curing process, the molecular movement of the substrate surface will also be accelerated, so that the substrate surface can be embedded in part of the molecules or atoms of the coating, and the atoms or molecules in the coating can also enter the molecular or atomic layer of the substrate surface, so that the bonding between the substrate and the coating is more closely, further improving the adhesion of the coating.

[0085] In addition, since the aluminum pigment in the paint is a paint with aluminum powder as the main component, the aluminum powder will oxidize to form a dense protective film during the high temperature curing process in the air atmosphere, thereby improving the corrosion resistance of the coating.

[0086] Therefore, the coating method of the present application cooperates with the use of the above-mentioned wide temperature range high temperature lubricating paint, which can provide a high-strength coating with strong adhesion, impact resistance, heat resistance, thermal shock resistance, wide temperature range adaptation, corrosion resistance, wear resistance, and high temperature lubrication.

[0087] In a sixth aspect, the present application provides a coating prepared by the coating method of the above-mentioned fifth aspect, wherein the thickness of the coating is 15-30 μm.

[0088] The main performance indicators of the wide temperature range high temperature resistant solid lubricating coating of the present application are as follows:

[0089] (1) Coating appearance: black gray (cobalt black as an anti-wear pigment, the specific color is related to the color of the anti-wear pigment), uniform, no obvious defects.

[0090] (2) Coating adhesion: 1 level (GB / T 9286).

[0091] (3) Coating flexibility: 1-2 mm, GB / T 1731.

[0092] (4) Coating impact resistance: 50 cm, GB / T 1732.

[0093] (5) Coating heat resistance: 800±10℃, constant temperature for 12h, the coating is intact, no cracks, no softening, no falling off, no bubbles and other phenomena, and the coating adhesion is 1 level.

[0094] (6) Coating thermal shock resistance: thermal shock test from room temperature to 800℃, 50 times, the coating is intact, no cracks, no falling off and other phenomena.

[0095] (7) In the wide temperature range of 20℃-800℃, the friction coefficient is 0.1-0.2, and the test conditions are: ball-on-disc contact, reciprocating wear, load 10N, frequency 2Hz, amplitude 6mm, and the counter is 6mm ZrO2 ball.

[0096] (8) In the wide temperature range of 20-800℃, the wear rate is all <10-5m3 / Nm, and the test conditions are the same as above.

[0097] (9) Neutral salt spray test, 500h, no corrosion on the coating surface.

[0098] The beneficial effects of the coating of the present application are as described above for the coating method of the fifth aspect, and will not be repeated here.

[0099] Embodiment

[0100] Embodiment 1

[0101] A wide-temperature-range high-temperature lubricating coating was prepared according to the following method:

[0102] S101, 6 parts of aminated boron nitride, 3 parts of low-melting-point glass powder, 3 parts of aluminum pigment, 10 parts of anti-wear pigment (cobalt black), and 25 parts of water were added to a ball mill device, and ball milling was performed at a speed of 400 rpm for 48 h to obtain a slurry.

[0103] S102, 25 parts by weight of an aqueous dispersion of a binder (solid content 65%) and 25 parts of water were added to the slurry, and stirring and mixing were performed to obtain a premixed coating.

[0104] S103, the premixed coating was added to a high-speed dispersion machine, and stirring and dispersion were performed at a stirring speed of 4500 rpm for 10 min to obtain a finished wide-temperature-range high-temperature lubricating coating.

[0105] Embodiment 2

[0106] A wide-temperature-range high-temperature lubricating coating was prepared according to the following method:

[0107] S201, 8 parts of aminated boron nitride, 3 parts by weight of low-melting-point glass powder, 3 parts of aluminum pigment, 8 parts of anti-wear pigment (cobalt black), and 25 parts of water were added to a ball mill device, and ball milling was performed at a speed of 600 rpm for 48 h to obtain a slurry.

[0108] S202, 25 parts by weight of an aqueous dispersion of a binder (solid content 65%) and 25 parts of water were added to the slurry, and stirring and mixing were performed to obtain a premixed coating.

[0109] S203, the premixed coating was added to a high-speed dispersion machine, and stirring and dispersion were performed at a stirring speed of 4500 rpm for 10 min to obtain a finished wide-temperature-range high-temperature lubricating coating.

[0110] Embodiment 3

[0111] A wide-temperature-range high-temperature lubricating coating was prepared according to the following method:

[0112] S301, 15 parts of aminated boron nitride, 5 parts of low-melting glass powder, 5 parts of aluminum pigment, 20 parts of anti-wear pigment (cobalt black), and 30 parts of water were added into a ball mill device, and were ball-milled and ground at a rotating speed of 400 rpm for 12 h to obtain a slurry.

[0113] S302, 25 parts of an aqueous dispersion of a binder (65% solid content) was added into the slurry, and 30 parts of water was further added, and the mixture was stirred and mixed uniformly to obtain a premixed coating.

[0114] S303, the premixed coating was added into a high-speed dispersion machine, and was stirred and dispersed at a stirring speed of 5000 rpm for 10-20 min to obtain a finished product of the wide-temperature-range high-temperature lubricating coating.

[0115] Example 4

[0116] A wide-temperature-range high-temperature lubricating coating was prepared by the following method:

[0117] S401, 5 parts of aminated boron nitride, 4 parts of low-melting glass powder, 4 parts of aluminum pigment, 15 parts of anti-wear pigment (cobalt black), and 10 parts of water were added into a ball mill device, and were ball-milled and ground at a rotating speed of 500 rpm for 36 h to obtain a slurry.

[0118] S402, 35 parts of an aqueous dispersion of a binder (65% solid content) was added into the slurry, and 10 parts of water was further added, and the mixture was stirred and mixed uniformly to obtain a premixed coating.

[0119] S403, the premixed coating was added into a high-speed dispersion machine, and was stirred and dispersed at a stirring speed of 2000 rpm for 20 min to obtain a finished product of the wide-temperature-range high-temperature lubricating coating.

[0120] Comparative Example 1

[0121] The remaining operations were the same as in Example 1, except that no fumed silica and boron oxide was added in the binder.

[0122] 1. Preparation of aminated boron nitride

[0123] The aminated boron nitride in the above examples and comparative examples was prepared by the following method:

[0124] The boron nitride powder, urea, and deionized water were added into a ball mill device, and were ball-milled and ground at a rotating speed of 500 rpm for 72 h to obtain a broken slurry.

[0125] The broken slurry was suction-filtered, the filter cake was washed with deionized water until the filtrate was neutral, and then was dried to obtain aminated boron nitride powder.

[0126] The mass ratio of the boron nitride, urea, and water was 1:30:30.

[0127] 2. Preparation of the binder

[0128] 1) The binder used in the above Example 1 and Example 3, Example 4 was prepared as follows:

[0129] Z101, Chromium trioxide was added to a 60wt% aqueous phosphoric acid solution, stirred and dissolved, and heated to 85°C to obtain an acidic solution;

[0130] Z102, Aluminum hydroxide was added to the acidic solution, and after complete dissolution, the temperature was raised to 120°C for 2h to obtain a precursor gel solution;

[0131] Z103, Fumed silica and boron oxide were added to the precursor gel solution, and after 2h of reaction, the temperature was allowed to cool to room temperature to obtain the binder.

[0132] The molar ratio of aluminum hydroxide to phosphoric acid was 0.26:1;

[0133] The molar ratio of aluminum hydroxide to chromium trioxide was 3.4:1;

[0134] The amount of fumed silica was 1.9% of the mass of the binder;

[0135] The amount of boron oxide was 1.4% of the mass of the binder.

[0136] 2) The binder used in the above Example 2 was prepared as follows:

[0137] Z201, Chromium trioxide was added to a 60wt% aqueous phosphoric acid solution, stirred and dissolved, and heated to 85°C to obtain an acidic solution;

[0138] Z202, Aluminum hydroxide was added to the acidic solution, and after complete dissolution, the temperature was raised to 120°C for 2h to obtain a precursor solution;

[0139] Z203, Fumed silica and boron oxide were added to the precursor solution, and after 2h of reaction, the temperature was allowed to cool to room temperature to obtain the binder.

[0140] The molar ratio of aluminum hydroxide to phosphoric acid was 0.35:1;

[0141] The molar ratio of aluminum hydroxide to chromium trioxide was 3:1;

[0142] The amount of fumed silica was 2.4% of the mass of the binder;

[0143] The amount of boron oxide was 1.6% of the mass of the binder.

[0144] The aqueous dispersion of the above binder was obtained by adding deionized water to the binder to obtain a dispersion with the corresponding solid content.

[0145] 3. Coating preparation

[0146] The coating prepared by the method of the above-mentioned Examples 1-4 and Comparative Example 1 was made into a corresponding coating according to the following method.

[0147] The wide-temperature-range high-temperature lubricating coating was uniformly coated on the surface of the treated substrate by spraying, and was left to dry for 8 h to form a pre-coating layer on the surface of the substrate.

[0148] The substrate with the pre-coating layer attached to the surface was placed in a heating device and heated in an air atmosphere. The heating process was first raised from room temperature to 150°C at a heating rate of 3°C / min, and was kept at 150°C for 1.5 h for curing. Then, the temperature was raised to 305°C at a heating rate of 2°C / min, and was kept at 305°C for 1.5 h for curing, and was then naturally cooled to form a coating on the surface of the substrate. The thickness of the cured coating was controlled to be 20 pm ± 0.5 pm.

[0149] Experimental examples

[0150] The coating prepared by the method of the above-mentioned Examples 1-4 and Comparative Example 1 was subjected to the following experiments:

[0151] Experimental example 1

[0152] After the substrate with the coating was oxidized at 900°C for 48 h, the adhesion of the coating was tested according to GB / T 5210-2006 “Paints and varnishes - Pull-over adhesion test”. The substrate with the coating was subjected to neutral salt spray test according to the method of GB / T 10125-2021 “Artificial atmosphere corrosion testing - Salt spray tests” (the sample was not subjected to grid processing, and the test was terminated when rust spots appeared on the sample). The results are shown in Table 1:

[0153] Coating adhesion (MPa) Salt spray resistance (h) Example 1 15.91 1555 Example 2 12.23 1472 Example 3 15.46 1485 Example 4 14.98 1508 Comparative Example 1 8.77 456

[0154] At the same time Figure 1 The test figures of the coating adhesion of the coating of Example 1 Figure 1 (a) and Example 2 Figure 1 (b) after 900°C thermal oxidation for 48 h are provided.

[0155] Experimental example 2

[0156] After the coating of Example 1 and Example 2 was subjected to thermal shock test (room temperature-800°C thermal shock test, i.e. the coating was heated to 800°C and then quickly cooled in cold water at room temperature) for 50 times according to the method provided in GB / T 42259-2022 “Metallic and other inorganic overcoat thermal barrier coating thermal cycle and thermal shock resistance test method”, the appearance of the coating was observed. The results are shown in Figure 2 , wherein Figure 2 (a) is the appearance figure of the coating of Example 1 before thermal shock, Figure 2Image (b) shows the appearance of the coating after thermal shock in Example 1. Figure 2 Image (c) shows the appearance of the coating before thermal shock in Example 2. Figure 2 Image (d) shows the appearance of the coating after thermal shock in Example 2. Figure 2 As can be seen from the images, after the thermal shock test, the appearance of the coatings in Examples 1 and 2 did not change significantly. This indicates that the coatings prepared by the method of this application have excellent thermal shock resistance. In other words, the coatings made by the coatings of this application can be used in a wide temperature range of room temperature to 800°C and exhibit superior performance.

[0157] Experimental Example 3

[0158] In Examples 1 and 2, the coatings were oxidized at 800℃ for 12 hours, and then subjected to friction experiments. A CSM friction machine was used with 6mm alumina ceramic balls, a frequency of 2Hz, a friction time of 30 minutes, a friction length of 5mm, a load of 5N, and a reciprocating dry friction method. The coefficient of friction was measured, and the results are as follows: Figure 3 As shown.

[0159] Figure 3 The anomaly in the friction coefficient curve after high-temperature oxidation in Example 1 at 1300s was caused by measurement error. Figure 3 The friction coefficient curves show that after high-temperature oxidation, the friction coefficients of the coatings in Examples 1 and 2 remain in the low friction coefficient range of about 0.15 within the test time. This indicates that the coating prepared by the present application has excellent anti-friction properties, and also shows that it has low wear rate and good lubricity under high temperature conditions.

[0160] Figure 4 and Figure 5 The XRD patterns of unmodified chromium aluminum phosphate binder (i.e., the precursor solution) and modified chromium aluminum phosphate binder (i.e., the binder prepared by the method of this application) at different temperatures are shown. It can be found that the unmodified binder completely transforms into a crystalline phase after high-temperature heating, generating large stresses during the high-temperature phase transformation, resulting in poor heat resistance and thermal shock resistance of the coating. The modified resin retains a large amount of amorphous phase at high temperatures, alleviating the thermal stress caused by the high-temperature phase transformation during thermal cycling and improving the heat resistance and thermal shock resistance of the coating.

[0161] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that; it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for producing a binder, characterized by, The method comprises the following steps: adding chromium trioxide into phosphoric acid aqueous solution, stirring and dissolving, and heating to 80-85℃ to obtain an acidic solution; adding aluminum hydroxide into the acidic solution, heating to 100-140℃ after complete dissolution, and keeping for 1-3h to obtain a precursor solution; adding fumed silica and boron oxide into the precursor solution, keeping for 1-3h, and naturally cooling to room temperature to obtain a binder; the concentration of the phosphoric acid aqueous solution is 55-70wt%; the molar ratio of aluminum hydroxide to phosphoric acid is 0.25-0.4:1; the molar ratio of aluminum hydroxide to chromium oxide is 2-4:1; the amount of fumed silica is 1-5% of the mass of the binder; the amount of boron oxide is 1-5% of the mass of the binder.

2. A binder, characterized by The method is prepared by the method provided in claim 1.

3. A process for the preparation of a wide temperature range high temperature lubricating coating characterized in that, The method comprises the following steps: proportionally adding aminated boron nitride, low-melting-point glass powder, aluminum pigment, and anti-wear pigment filler into a crushing device, adding water, and crushing and grinding for 12-48h to obtain a slurry; adding an aqueous dispersion of the binder provided in claim 2 into the slurry, adding water, stirring and mixing, and pre-mixing the coating; stirring and dispersing the pre-mixed coating to obtain a finished wide-temperature-range high-temperature lubricating coating.

4. The method for preparing a wide-temperature-range high-temperature lubricating coating according to claim 3, characterized in that, The aminated boron nitride is prepared by the following method: adding boron nitride powder, urea, and deionized water into a ball mill device, ball milling and crushing at a speed of 400-600rpm for 24-72h to obtain a crushed slurry; suction-filtering the crushed slurry, washing the filter cake with deionized water until the filtrate is neutral, and drying to obtain aminated boron nitride powder; the mass ratio of the boron nitride, urea, and water is 1-5:30-60:20-40.

5. The method of claim 3, wherein the wide-temperature-range high-temperature lubricating coating is prepared by mixing the base oil, the thickener, the extreme-pressure agent, the antioxidant, the anti-wear agent, the friction modifier, and the corrosion inhibitor. The added amount of the aqueous dispersion of the binder is 25-35 parts by weight, the added amount of the aminated boron nitride is 5-15 parts by weight, the added amount of the low-melting-point glass powder is 3-5 parts by weight, the added amount of the aluminum pigment is 3-5 parts by weight, the added amount of the anti-wear pigment filler is 10-20 parts, and the added amount of water is 20-60 parts.

6. The method of claim 3, wherein the wide-temperature-range high-temperature lubricating coating is prepared by mixing the base oil, the thickener, the extreme-pressure agent, the antioxidant, the anti-wear agent, the friction modifier, and the corrosion inhibitor. The solid content in the aqueous dispersion of the binder is 60-65wt%; during the stirring and dispersing process, the stirring speed is 2000-5000rpm, and the dispersing time is 10-20min.

7. A wide temperature range high temperature lubricating coating characterized by, The method is prepared by any one of the methods provided in claims 3-6.

8. A coating preparation method, characterized by, The method comprises the following steps: uniformly applying the wide-temperature-range high-temperature lubricating coating provided in claim 7 to the surface of a substrate, leaving to dry for 1-18h, and forming a pre-coated layer on the surface of the substrate; placing the substrate with the pre-coated layer attached to the surface into a heating device, heating and curing in an air atmosphere, and forming a coating layer on the surface of the substrate; during the heating and curing process, first increasing the temperature from room temperature to 120-150℃ at a rate of 2-3℃ / min, and keeping for 1-1.5h; then increasing the temperature to 305-315℃ at a rate of 1-2℃ / min, and keeping for 1-1.5h, and then naturally cooling; the thickness of the coating layer after curing is 15-30μm.

9. A coating characterized in that, The coating layer is prepared by the preparation method provided in claim 8, and the thickness of the coating layer is 15-30μm.

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