Environment-triggered anticorrosive coating for heat pipe and preparation method and application thereof

Abstract

The present application relates to the technical field of anticorrosive paint, and particularly relates to an environment-triggered heat pipe anticorrosive paint, a preparation method and application thereof. The heat pipe anticorrosive paint comprises component A and component B, wherein the mass ratio of component A and component B is 30:1-10:1. When applied, the heat pipe anticorrosive paint is coated on the inner wall of a heat pipe to form a coating, a modified protective layer is formed by using a silane coupling agent and graphene, or a silane coupling agent and hydrophobic PDMS, so that the aluminum powder in the coating is gradually exposed and oxidized into aluminum oxide after being affected by a high-temperature and high-pressure boiling environment. In this process, not only the water and oxygen permeating into the coating are consumed, but also a continuous and dense aluminum oxide barrier is formed inside the coating. This "environment-triggered" self-adaptive mechanism utilizes the special application environment of high-temperature and high-pressure boiling, and is different from the traditional pre-oxidation technology, and has potential advantages of dynamic response and self-repairing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of anticorrosive coatings, in particular to an environment-triggered heat pipe anticorrosive coating, a preparation method thereof and an application thereof. BACKGROUND

[0002] With the rapid development of the national economy and the continuous improvement of urbanization level, the scale of centralized heating in winter in northern cities is expanding, and the laying area of heat pipe networks is increasing year by year. At present, the heating in northern cities is still mainly in the form of pipeline transportation of hot water, and the quality and performance of the heat pipe directly affect the operation effect of the entire centralized heating system.

[0003] After the heat pipe is put into use, due to the high temperature of the hot water transmitted, the inner wall of the pipe is exposed to a high-temperature environment for a long time, and is eroded by dissolved oxygen and other corrosive substances in the water, and the corrosion degree will increase year by year. This corrosion phenomenon will cause the pipe wall to gradually thin, not only shortening the service life of the equipment, but also possibly damaging the normal operation of the entire urban heating pipe network. The problem of corrosion of the inner wall of the heat pipe has become the focus of attention of various departments of the heating system. At present, the commonly used corrosion prevention measures include adding corrosion inhibitors such as sulfites, or slowing down the corrosion by increasing the pH value of the circulating water and improving the water quality. However, these methods have certain limitations. For example, adding chemical agents may cause environmental pollution of circulating water discharge, and relying on water treatment equipment to improve water quality will significantly increase the operating cost of the heating unit.

[0004] In contrast, coating a corrosion-resistant coating on the inner wall of the heat pipe is an efficient, economical and environmentally friendly solution. This method can effectively isolate the corrosive components in the hot water medium from contacting the metal surface of the pipe by forming a corrosion-resistant protective layer on the inner wall of the pipe, thereby significantly reducing the corrosion rate. The corrosion-resistant coating not only prolongs the service life of the pipe, reduces the maintenance frequency and replacement cost, but also ensures the long-term stable operation of the heating system. At the same time, the coating technology is flexible and convenient to apply, and does not require large-scale modification of existing facilities, and therefore has wide promotional value.

[0005] However, the current traditional coating technology faces many challenges in practical application. For example, the coating is prone to cracking, peeling and other problems under high temperature and high pressure, resulting in a decrease in corrosion prevention effect; the high temperature resistance and adhesion of some coating materials are insufficient, making it difficult to meet the long-term operation requirements of the heat pipe. In addition, the barrier performance and drag reduction effect of the existing coating are limited, making it difficult to further improve the operation efficiency of the pipe.

[0006] In order to solve the above problems, there is an urgent need for a new coating material with excellent adhesion, long-term corrosion resistance and good drag reduction performance in a high-temperature environment. SUMMARY

[0007] The present application aims to at least solve one of the technical problems existing in the related art. To this end, a first object of the present application is to provide an environment-triggered heat pipe anticorrosive coating, a second object of the present application is to provide a preparation method of the environment-triggered heat pipe anticorrosive coating, and a third object of the present application is to provide an application of the environment-triggered heat pipe anticorrosive coating.

[0008] To achieve the first object, the technical solution adopted by the present application is as follows:

[0009] The environment-triggered heat pipe anticorrosive coating comprises an A component and a B component, and the mass ratio of the A component to the B component is 30:1-10:1.

[0010] The components of the A component and their mass percentages are as follows:

[0011] Silicone epoxy resin 10-20%;

[0012] Silicone resin 30-50%;

[0013] Modified aluminum powder 5-30%;

[0014] Nano polytetrafluoroethylene powder 5-10%;

[0015] Layered nanoclay 5-20%;

[0016] Glass flake 5-20%;

[0017] Additive 0.2-1%;

[0018] Organic solvent I 10-30%;

[0019] The components of the B component and their mass percentages are as follows:

[0020] Silane coupling agent I 40-60%;

[0021] Epoxy curing agent 10-20%;

[0022] Organic solvent II 40-50%;

[0023] The modified aluminum powder is obtained by modifying flaky aluminum powder with one or more of graphene oxide, silane coupling agent II and PDMS.

[0024] PDMS is polydimethylsiloxane.

[0025] The anticorrosive coating provided by the present application is a coating designed for the corrosion problem of the inner wall of a heat pipe. When applied, the heat pipe anticorrosive coating is coated on the inner wall of the heat pipe to form a coating. Under the triggering of the high-temperature and high-pressure boiling application environment, the activity of the aluminum powder inside the coating increases, and can react with the diffused water and oxygen to form a dense aluminum oxide shielding layer in situ, while consuming part of the water and oxygen, actively blocking the diffusion of water and oxygen, and enhancing the overall anticorrosive effect. To prevent rapid oxidation of the aluminum powder and delay the oxidation process, the modified aluminum powder in component A of the present application is prepared by modifying the aluminum powder with graphene oxide and / or silane coupling agent II, and then coating with PDMS. The physical barrier and hydrophobicity of the modified aluminum powder delay the oxidation of the aluminum powder and achieve controllability of the oxidation reaction. In addition, the silane coupling agent forms a chemical bond between the aluminum powder and the resin matrix, improving the dispersibility of the aluminum powder and the interfacial compatibility with the resin, and forming a more continuous and efficient protective layer.

[0026] At the same time, the heat pipe anticorrosive coating uses high-temperature resistant silicone resin as the main film-forming component, so that the prepared coating has excellent high-temperature resistance, and the auxiliary addition of silicone-modified epoxy resin can greatly improve the adhesion of the coating; the labyrinth effect of the layered nanoclay and glass fiber in the coating, combined with the swelling properties of the layered nanoclay, can improve the barrier performance of the coating; the low-surface-energy nano-polytetrafluoroethylene has self-lubricating properties, which can improve the hydrophobicity of the coating and further improve the drag reduction characteristics of the coating. The coating formed by the heat pipe anticorrosive coating provided by the present application not only solves the problem of corrosion of the inner wall of the heat pipe and the short service life of the heat pipe, but also has excellent drag reduction effect, which can improve the heat delivery efficiency, so it can solve the problem of high investment cost of the heat supply system.

[0027] Preferably, the preparation method of the modified aluminum powder comprises the following steps:

[0028] S10, pretreating flaky aluminum powder to remove oxides on the surface thereof to obtain pretreated flaky aluminum powder;

[0029] S20, surface modifying the pretreated flaky aluminum powder with graphene oxide and a reducing agent to obtain graphene-coated aluminum powder;

[0030] S30, surface activating the graphene-coated aluminum powder with a silane coupling agent II to obtain modified aluminum powder modified with graphene and the silane coupling agent II.

[0031] Preferably, the preparation method of the modified aluminum powder comprises the following steps:

[0032] S100, pretreating flaky aluminum powder to remove oxides on the surface thereof to obtain pretreated flaky aluminum powder;

[0033] S200, surface activation of the pretreated flaky aluminum powder by using silane coupling agent II to obtain aluminum powder coated with silane coupling agent II;

[0034] S300, mixing of the polydimethylsiloxane and the crosslinking agent, addition of the catalyst, stirring to form a uniform matrix;

[0035] S400, addition of the aluminum powder coated with silane coupling agent II in step S200 to the matrix, solidification and drying to obtain modified aluminum powder coated with PDMS and silane coupling agent II.

[0036] Preferably, the layered nanoclay is selected from one or more of montmorillonite powder, vermiculite powder, and hydrotalcite powder;

[0037] The epoxy curing agent is selected from an amine-based epoxy curing agent;

[0038] The organic solvent I and the organic solvent II are each independently selected from n-butanol and / or dimethylbenzene;

[0039] The silane coupling agent I is selected from a silane coupling agent containing amino, epoxy, and methacryloyloxy functional groups, preferably any one of aminopropyltriethoxysilane, glycidyloxypropyltrimethoxysilane, and methacryloyloxypropyltrimethoxysilane.

[0040] Preferably, the particle size of the nano-polytetrafluoroethylene powder is 50-500 nm.

[0041] Preferably, the silane coupling agent II is selected from any one of amino, epoxy, and methacryloyloxy silane coupling agents.

[0042] Preferably, the reducing agent is selected from sodium borohydride, hydrazine hydrate, ascorbic acid, and glucose.

[0043] Preferably, the crosslinking agent in step S300 includes an epoxy compound-based crosslinking agent, an epoxy resin-based crosslinking agent, an organic peroxide-based crosslinking agent, or a siloxane-based crosslinking agent, but is not limited thereto.

[0044] Preferably, the additive includes a dispersant and / or a defoaming agent, the dispersant is not further limited, for example, can be an alkylphenol polyoxyethylene ether or BYK-220S, but is not limited thereto; the defoaming agent is not further limited, for example, can be a polyamide wax, but is not limited thereto.

[0045] To achieve the second object, the technical solution adopted by the present application is:

[0046] The preparation method of the environment-triggered heat pipe anticorrosive coating is used to prepare the environment-triggered heat pipe anticorrosive coating described in any one of the above, and includes the following steps:

[0047] S1, preparing component A, the process is as follows:

[0048] The silicone epoxy resin and the silicone resin are dissolved in the organic solvent I, then the additives are dispersed and defoamed, then the modified aluminum powder, the layered nanoclay, the glass flake and the nano polytetrafluoroethylene powder are added and dispersed and ground to obtain the component A;

[0049] S2, preparing component B, the process is as follows:

[0050] The silane coupling agent and the epoxy curing agent are dissolved in the organic solvent II to obtain the component B;

[0051] S3, the component A and the component B are mixed uniformly at a mass ratio of 30:1 to 10:1 to obtain the environment-triggered heat pipe anticorrosive coating.

[0052] In order to achieve the third object, the technical scheme adopted by the present application is:

[0053] The application of the environment-triggered heat pipe anticorrosive coating, the environment-triggered heat pipe anticorrosive coating described in any one of the above, the application comprises an inner wall coating for a heat pipe system, and the thickness of the coating is 150-500 mu m.

[0054] Further, the heat pipe system comprises a water supply section and / or a return water section.

[0055] The one or more technical solutions in the embodiments of the present application at least have one of the following technical effects:

[0056] The present application provides an environment-triggered heat pipe anticorrosive coating and a preparation method and application thereof. The heat pipe anticorrosive coating is a two-component reactive coating, comprising component A and component B. The component A comprises a silicone epoxy resin, a silicone resin, a modified aluminum powder, a nano polytetrafluoroethylene powder, a layered nanoclay, a glass flake, an additive and an organic solvent I. The component B comprises a silane coupling agent I, an epoxy curing agent and an organic solvent II.

[0057] The modified aluminum powder in the component A is prepared by modifying the aluminum powder with graphene oxide and / or silane coupling agent II, and then coating with PDMS. In application, the heat pipe anticorrosive coating is coated on the inner wall of the heat pipe to form a coating. The silane coupling agent and / or graphene oxide form a modified protective layer with the hydrophobic PDMS, so that the aluminum powder is gradually exposed and oxidized to alumina under the influence of high temperature and high pressure boiling environment. In this process, not only the water and oxygen that penetrate into the coating are consumed, but also a continuous and dense alumina barrier is formed inside the coating. This "environment-triggered" self-adaptive mechanism takes advantage of the special application environment of high temperature and high pressure boiling, which is different from the traditional pre-oxidation technology, and has the potential advantages of dynamic response and self-repair.

[0058] II. The modification of the interface between the aluminum powder and the coating matrix by a silane coupling agent improves the dispersion of the aluminum powder in the coating, thereby forming a more continuous and efficient protective layer during curing, and further improving the high-temperature resistance, high-pressure resistance and corrosion resistance of the coating.

[0059] III. The use of modified aluminum powder in combination with high-temperature resistant resin and barrier filler can achieve more excellent high-temperature corrosion resistance. The high-temperature resistant silicone resin in component A is the main film-forming material, which provides excellent high-temperature resistance and protects the inner wall of the heat pipe under high temperature for a long time. The silicone epoxy resin is an epoxy resin modified by silicone. Epoxy resin is a high molecular compound with excellent chemical stability and mechanical properties. It contains a large number of polar groups in its molecular structure, which can produce strong attractive force with the atoms or molecules on the surface of the heat pipe inner wall, forming chemical bonds or physical adsorption force, thereby achieving good adhesion. The layered nanoclay and glass fiber in the coating can play a material barrier role, and the swelling and densification properties of the layered nanoclay can improve the corrosion resistance.

[0060] IV. The in-situ generated dense aluminum oxide can reduce the roughness of the coating and improve the drag reduction performance of the coating. At the same time, in combination with low-surface-energy silicone resin and nanoscale polytetrafluoroethylene, the coating has strong self-lubricating properties, improves the hydrophobic properties of the coating, and further improves the drag reduction characteristics.

[0061] V. The preparation method provided by the present application has mild reaction conditions and simple operation, and is easy to scale up.

[0062] Additional aspects and advantages of the present application will be partially given in the following description, partially will become apparent from the following description, or will be understood by those skilled in the art through the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 is a display diagram of the state of the coating prepared by the anti-corrosion coating in Example 1 before and after temperature and pressure alternating test for different cycle times provided by the test example of the present application.

[0064] Figure 2 is a display diagram of the state of the coating prepared by the anti-corrosion coating in Example 2 after different cycle times provided by the test example of the present application.

[0065] Figure 3 is a display diagram of the state of the coating prepared by the anti-corrosion coating in Comparative Example 2 before and after 20 cycles of temperature and pressure alternating test provided by the test example of the present application. DETAILED DESCRIPTION

[0066] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below in connection with specific embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present application. The following embodiments are used to illustrate the present application, but cannot be used to limit the scope of the present application.

[0067] The environment-triggered heat pipe anticorrosive coating comprises an A component and a B component, and the mass ratio of the A component to the B component is 30:1-10:1.

[0068] The components of the A component and the mass percentages thereof are as follows:

[0069] Silicone epoxy resin 10-20%;

[0070] Silicone resin 30-50%;

[0071] Modified aluminum powder 5-30%;

[0072] Nano polytetrafluoroethylene powder 5-10%;

[0073] Layered nano clay 5-20%;

[0074] Glass flake 5-20%;

[0075] Additive 0.2-1%;

[0076] Organic solvent I 10-30%;

[0077] The components of the B component and the mass percentages thereof are as follows:

[0078] Silane coupling agent I 40-60%;

[0079] Epoxy curing agent 10-20%;

[0080] Organic solvent II 40-50%;

[0081] The modified aluminum powder is modified by graphene oxide and / or silane coupling agent II, and then coated by hydrophobic PDMS.

[0082] The PDMS is polydimethylsiloxane.

[0083] In the following examples, the experimental methods used are conventional methods, and the materials, reagents, etc. used are obtained from commercial channels, unless otherwise specified, according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0084] Example 1

[0085] The components of the A component and their mass percentages are shown in the following table:

[0086]

[0087] The components of the B component and their mass percentages are shown in the following table:

[0088]

[0089] I. Method I for modifying aluminum powder, the process is described as follows:

[0090] 20 g of flaky aluminum powder (20 pm) was immersed in 100 mL of ethanol solution containing 1 g of amino silane coupling agent (KH550), and after ultrasonic dispersion for 30 min, a mixture was obtained. The mixture was placed in a 60°C oven for drying for 2 h to complete the activation of the aluminum powder surface.

[0091] After mixing PDMS prepolymer Sylgard 184 (72 g) with crosslinking agent ethyl silicate 40 (7.2 g), adding catalyst dibutyltin dilaurate (0.4 g), and stirring to form a uniform matrix, the aforementioned activated aluminum powder was added to the matrix. After mechanical stirring at a speed of 2000 rpm for 30 min, a mixture I was obtained. After transferring it to a vacuum drying oven (-0.1 MPa) for 20 min of degassing, it was pre-cured at 60°C for 4 h, and then the temperature was raised to 150°C for final curing for 0.5 h, to obtain a complete PDMS-aluminum powder composite, i.e. modified aluminum powder.

[0092] II. Method II for modifying aluminum powder, the process is described as follows:

[0093] 10 g of flaky aluminum powder (20 pm) was immersed in 100 mL of ethanol solution containing 1 g of amino silane coupling agent (KH550), and after ultrasonic dispersion for 20 min, a mixture was obtained. The mixture was placed in a 60°C oven for drying for 2 h to complete the activation of the aluminum powder surface.

[0094] After mixing PDMS prepolymer Sylgard 184 (36 g) with crosslinking agent ethyl silicate 40 (3.6 g), adding catalyst dibutyltin dilaurate (0.2 g), and stirring to form a uniform matrix, the aforementioned activated aluminum powder was added to the matrix and dispersed by a three-roll mill. After transferring it to a vacuum drying oven (-0.1 MPa) for 20 min of degassing, it was pre-cured at 60°C for 3 h, and then the temperature was raised to 120°C for final curing for 1 h, to obtain a complete PDMS-aluminum powder composite, i.e. modified aluminum powder.

[0095] Compared with modification method I, modification method II can adapt to faster crosslinking of thinner film layer, and the obtained coating layer is more uniform and complete, and the residual amount of reducing agent is lower. The following preparation process of heat pipe anticorrosive coating uses the modified aluminum powder obtained by method II.

[0096] The preparation process of heat pipe anticorrosive coating is as follows:

[0097] After the organic silicon epoxy resin and the organic silicon resin are added to the production cylinder, n-butanol / dimethylbenzene mixed solvent is added, and stirring is performed at a speed of 300 rpm for 5 min. The dispersing agent and the defoaming agent are added during stirring;

[0098] Subsequently, the modified aluminum powder, the layered nano clay, the glass flake, and the nano polytetrafluoroethylene powder are added, and stirring is performed at a speed of 800 rpm for 60 min. Then, the obtained mixture is ground to have a particle size of less than 50 μm, and component A is obtained.

[0099] The silane coupling agent and the epoxy curing agent are added to the n-butanol / dimethylbenzene mixed solvent in a proportion, and stirring is performed at a speed of 600 rpm for 10 min, and component B is obtained.

[0100] Components A and B are mixed in a mass ratio of 18:1, and stirring is performed for 5 min, and the environment-triggered heat pipe anticorrosive coating (100 g) is obtained.

[0101] Example 2

[0102] The components and the mass percentages of component A are shown in the following table:

[0103]

[0104] The components and the mass percentages of component B are shown in the following table:

[0105]

[0106] The preparation process of the heat pipe anticorrosive coating is the same as that in example 1.

[0107] Example 3

[0108] The components and the mass percentages of component A are shown in the following table:

[0109]

[0110] The components and the mass percentages of component B are shown in the following table:

[0111]

[0112] The preparation process of the modified aluminum powder in component A is as follows:

[0113] 10 g of flaky aluminum powder (15 pm) was placed in 100 ml of dilute hydrochloric acid with a mass concentration of 0.5%, and ultrasonic cleaning was performed for 8 min to remove the surface oxides. After cleaning, the aluminum powder was dried to obtain a pretreated aluminum powder.

[0114] Graphene oxide (400 mg) was dispersed in deionized water (200 ml) and ultrasonic treatment was performed to obtain a 0.2 mg / ml suspension. The pretreated aluminum powder (10 g) was added to the graphene oxide water suspension (200 ml), and after stirring and dispersing, the reducing agent hydrazine hydrate (200 mg) was added. The mixture was reacted in a water bath at 80°C for 5 h. The solid product was separated and washed and dried to obtain graphene-modified aluminum powder. The modified aluminum powder was dispersed in an alcohol / water solution (300 ml) of methacryloxypropyltrimethoxysilane, and the alcohol / water solution was a mixed solvent of ethanol and water (the volume ratio of ethanol to water was 5:1). Then, the mixture was stirred at 300 rpm at 120°C for 1 h. After separation, washing, and drying, a silane coupling agent and graphene-modified modified aluminum powder were obtained.

[0115] The preparation process of the heat pipe anticorrosive coating was the same as that of Example 1.

[0116] Example 4

[0117] The components and their mass percentages of the A component are shown in the following table:

[0118]

[0119] The components and their mass percentages of the B component are shown in the following table:

[0120]

[0121] The preparation process of the modified aluminum powder and the heat pipe anticorrosive coating was the same as that of Example 3.

[0122] Comparative Example 1

[0123] This comparative example is the same as Example 1 except that the modified aluminum powder in the A component is replaced by layered nanoclay.

[0124] Comparative Example 2

[0125] This comparative example is the same as Example 1 except that the modified aluminum powder in the A component is replaced by unmodified flaky aluminum powder.

[0126] Comparative Example 3

[0127] The comparative example will replace the modified aluminum powder in Example 1 with unmodified flaky aluminum powder and graphene oxide (mass ratio of flaky aluminum powder to graphene oxide is 9:1), in which the graphene is not pre-modified to the aluminum powder, but is directly mixed with other raw materials in the A component to prepare the anticorrosive coating.

[0128] The rest (including formula composition and preparation process) is the same as Example 1.

[0129] Test example

[0130] The anticorrosive coatings obtained in Examples 1-4 and Comparative Examples 1, 2 and 3 are all used to prepare coatings in the following way:

[0131] After the anticorrosive coating is sprayed onto the substrate using a liquid spray gun, the sample plate is placed in an oven at 150°C for 1h to obtain an anticorrosive coating, the thickness of which is controlled at 250-300µm.

[0132] The above obtained coating is tested for performance according to the following standards: adhesion test according to GB / T5210, pencil hardness according to GB / T6739, bending resistance according to SY / T0442-2018 Appendix C, impact resistance according to SY / T0442-2018 Appendix D, wear resistance according to GB / T1768, and water absorption weight gain rate according to T / CDHA 17-2024 Appendix A.

[0133] The temperature and pressure alternating test is performed according to T / CDHA 17-2024 Appendix C, and the specific test method is as follows: in deionized water, one cycle is continuous high temperature and high pressure (150°C, 2.5Mpa) for 24h and then continuous low temperature and low pressure (5°C, normal pressure) for 24h, after several cycles, the appearance of the coating is checked and the adhesion is tested, such as the number and size of coating bubbles, which meets the GB / T 30789.2 2(S2) level and above, and the coating has no peeling and cracking, and the adhesion of the sample is not less than 70% of the comparative sample, which is considered to pass the cycle. At the same time, the initial drag reduction performance of the coating is tested by measuring the pressure change of the coated and uncoated pipe sections, and calculating the drag reduction rate.

[0134] The test results are shown in Tables 1 and 2:

[0135] Table 1 Performance parameter test results of anticorrosive coating

[0136]

[0137] Table 2 Performance parameter test results of anticorrosive coating

[0138]

[0139] From the data provided in Table 1 and Table 2, it can be seen that Examples 1-4 all meet the following requirements:

[0140] Adhesion ≥ 10 MPa;

[0141] Pencil hardness ≥ 2H;

[0142] No cracking of the coating under 1° bending conditions;

[0143] No leakage points under 2.5 J impact;

[0144] Wear mass loss ≤ 100 mg, and mass gain ≤ 3% after boiling in water at 80°C for 28 days;

[0145] Contact angle ≥ 90°;

[0146] After application of the drag reduction coating, good energy saving and consumption reduction can be achieved, with a drag reduction rate of more than 40%;

[0147] Therefore, the corrosion protection coatings formed using the corrosion protection coatings of Examples 1-4 all exhibit excellent mechanical and drag reduction properties.

[0148] Coating temperature and pressure alternating performance is the most important evaluation index of the coating, and can most directly reflect the corrosion resistance and high temperature resistance of the coating in the actual environment. After 45 cycles of standard cycles, the number and size of bubbles of the coating of Example 1 and Example 4 are radiated in GB / T 30789.2 Grade 2 (S2) and above, and the coating has no peeling and no cracking, and the adhesion of the sample is ≥ 10 MPa.

[0149] The coating prepared using the corrosion protection coating of Example 1 is shown in the coating state display diagram before and after temperature and pressure alternating test (15 times, 30 times and 45 times), as shown in Figure 1 From the diagram, it can be seen that the silver aluminum powder on the surface of the coating slowly oxidizes into low-gloss alumina over time after high-temperature high-pressure boiling treatment, and no obvious bubbling phenomenon occurs on the surface of the coating after 45 cycles.

[0150] The coating prepared using the corrosion protection coating of Example 2 is shown in the coating state display diagram after different cycle times (5 times, 10 times and 20 times), as shown in Figure 2 From the diagram, it can be seen that the coating still has no peeling and no cracking, and the adhesion is ≥ 10 MPa. From Figure 2 It can also be seen that the process of high-gloss aluminum powder transforming into alumina has a reduced effect on high-temperature corrosion resistance, and there is slight damage to the surface after 20 cycles. The experimental results show that the effect of high-temperature corrosion resistance of the corrosion protection coating is reduced with the decrease of aluminum powder.

[0151] Comparative Example 1 is a coating without aluminum powder, Comparative Example 2 and Comparative Example 3 are coatings with unmodified aluminum powder.

[0152] The coating temperature pressure alternating test results show that, without aluminum powder, Comparative Example 1 coating has a large number of bubbles after only 5 cycles, which shows that in-situ oxidation of aluminum powder plays an important role in improving the performance of the coating.

[0153] Comparative Example 2 is a coating with unmodified aluminum powder, which can increase the cycle standard to 15 times, but is far lower than the 45 cycles of the coating with modified aluminum powder, and the results are shown in Figure 3 As can be seen from the figure, when the number of cycles increases to 20 times, the coating has a large number of bubbles.

[0154] From the above comparison, it can be seen that the unmodified aluminum powder has poor dispersion uniformity in the coating, and its rapid oxidation cannot achieve long-term stable protection of the substrate. Without the protection of PDMS, silane coupling agent and graphene, the aluminum powder is directly in contact with the hot water in the environment and rapidly oxidizes, causing rapid in-situ expansion, which destroys the surface integrity of the coating. The surface of the modified aluminum powder has a hydrophobic polymer layer and / or a physical barrier layer, which can hinder the direct contact of water molecules at high temperature, so that the oxidation reaction occurs relatively gently. In the reaction process, through controllable expansion and extrusion, the coating can realize filling and reduce the original defects, thereby improving its barrier performance.

[0155] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An environmentally triggered anticorrosive coating for a heat pipe, characterized by, The heat pipe anticorrosive coating comprises an A component and a B component, and the mass ratio of the A component to the B component is 30:1-10:

1. The components and their mass percentages of the A component are as follows: Silicone epoxy resin 10-20%; Silicone resin 30-50%; Modified aluminum powder 5-30%; Nano polytetrafluoroethylene powder 5-10%; Layered nanoclay 5-20%; Glass flake 5-20%; Additive 0.2-1%; Organic solvent I 10-30%; The components and their mass percentages of the B component are as follows: Silane coupling agent I 40-60%; Epoxy curing agent 10-20%; Organic solvent II 40-50%; The modified aluminum powder is obtained by modifying flaky aluminum powder with one or more of graphene oxide, silane coupling agent II and PDMS. PDMS is polydimethylsiloxane.

2. The environment-triggered heat pipe anticorrosive coating according to claim 1, wherein The preparation method of the modified aluminum powder comprises the following steps: S10, pretreating the flaky aluminum powder to remove oxides on the surface of the flaky aluminum powder to obtain pretreated flaky aluminum powder; S20, modifying the pretreated flaky aluminum powder with graphene oxide and a reducing agent to obtain graphene-coated aluminum powder; S30, activating the graphene-coated aluminum powder with silane coupling agent II to obtain modified aluminum powder modified with graphene and silane coupling agent II.

3. The environment-triggered heat pipe anticorrosive coating according to claim 1, wherein The preparation method of the modified aluminum powder comprises the following steps: S100, pretreating the flaky aluminum powder to remove oxides on the surface of the flaky aluminum powder to obtain pretreated flaky aluminum powder; S200, activating the pretreated flaky aluminum powder with silane coupling agent II to obtain aluminum powder coated with silane coupling agent II; S300, mixing polydimethylsiloxane and a crosslinking agent, adding a catalyst, and stirring to form a uniform matrix; S400, adding the aluminum powder coated with silane coupling agent II in step S200 to the matrix, and curing and drying to obtain modified aluminum powder coated with PDMS and silane coupling agent II.

4. The environment-triggered heat pipe anticorrosive coating material according to claim 1, wherein The layered nanoclay is selected from one or more of montmorillonite powder, vermiculite powder and hydrotalcite powder; The epoxy curing agent is selected from an amine-based epoxy curing agent; The organic solvent I and the organic solvent II are each independently selected from n-butanol and / or dimethylbenzene; The silane coupling agent I is selected from any one of silane coupling agents containing amino, epoxy and methacryloyloxy functional groups; The nano polytetrafluoroethylene powder has a particle size of 50-500 nm.

5. The environment-triggered heat pipe anticorrosive coating according to claim 2 or 3, wherein The silane coupling agent II is selected from any one of amino, epoxy and methacryloyloxy silane coupling agents.

6. The environment-triggered heat pipe anticorrosive coating according to claim 2, wherein The reducing agent is selected from sodium borohydride, hydrazine hydrate, ascorbic acid and glucose.

7. The environment-triggered heat pipe anticorrosive coating material according to claim 1, wherein The additive comprises a dispersant and / or a defoaming agent.

8. A method for preparing an environmentally triggered anticorrosive coating for a thermal conduit, characterized by, A process for preparing the environment-triggered heat pipe anticorrosive coating according to claim 1 comprises the following steps: S1, preparing the A component, the process being as follows: Dissolve the silicone epoxy resin and the silicone resin in the organic solvent I, then add the additive, disperse and defoam, and then add the modified aluminum powder, the layered nanoclay, the glass flake and the nano polytetrafluoroethylene powder, disperse and grind to obtain the A component; S2, preparing the B component, the process being as follows: The silane coupling agent I and the epoxy curing agent are dissolved in the organic solvent II to obtain the B component; S3, uniformly mixing the A component and the B component at a mass ratio of 30:1-10:1 to obtain the environment-triggered heat pipe anticorrosive coating.

9. Use of an environmentally triggered anticorrosive coating for a thermal conduit, characterized in that, The environment-triggered heat pipe anticorrosive coating according to claim 1, wherein the application comprises an inner wall coating for a heat pipe system, and the thickness of the coating is 150-500 µm.

10. The use of an environmentally triggered thermal conduit anticorrosive coating according to claim 9, wherein The heat pipe system comprises a water supply section and / or a return water section.

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