Alcohol amine low temperature cured high temperature corrosion resistant protective coating

Abstract

The application provides an alcohol amine low-temperature cured high-temperature corrosion resistant protective paint and belongs to the field of high-temperature corrosion resistant protective paint. The high-temperature corrosion resistant protective paint is prepared from aluminum dihydrogen phosphate or chromium doped aluminum dihydrogen phosphate as a base resin binder, mixed aluminum powder with different morphologies and sizes as a functional filler, small molecular weight organic alcohol amine compounds as a low-temperature curing agent, deionized water as a solvent, and wetting dispersants, additives and the like. The corrosion resistant paint has good high-temperature resistance and can be used for a long time below 600 DEG C, the complete curing temperature is as low as 80 DEG C, and the cured coating has good adhesion, flexibility, boiling water resistance and aviation fuel immersion resistance, and can solve the problems of the current inorganic phosphate corrosion resistant coating, such as brittleness, poor compactness and high curing temperature, and can be applied to the field of low-temperature curing high-temperature corrosion resistant protection.

Description

Technical Field

[0001] This invention relates to a low-temperature curing corrosion protective coating, and more particularly to a high-temperature corrosion protective coating that utilizes alkanolamines to achieve low-temperature curing, belonging to the field of surface protection technology. Background Technology

[0002] Inorganic phosphate-based high-temperature corrosion resistant protective coatings are widely used for long-term corrosion protection of components such as aero-engine honeycomb seals, gas turbines, and compressor blades due to their excellent high-temperature stability, chemical inertness, and resistance to immersion in aviation kerosene and thermal synthetic oils. However, traditional inorganic phosphate-based high-temperature corrosion resistant protective coatings require temperatures above 300℃ to cure, which is time-consuming and energy-intensive, posing significant challenges for large-area application and curing conditions. Furthermore, the cured coatings often exhibit poor density and high brittleness. Therefore, there is an urgent need to develop high-performance, low-temperature curing, high-temperature corrosion resistant protective coatings.

[0003] To reduce the curing temperature of inorganic phosphate composite coatings, scholars both domestically and internationally have conducted extensive research, developing various types of low-temperature curing agents such as ZnO, CuO, Cr2O3, and MgO. These low-temperature curing agents can significantly reduce the curing temperature of phosphate resins, and some can even achieve room temperature curing. However, the main problem is that the addition of these metal compound low-temperature curing agents reduces the bonding strength of the coating. After curing, the adhesion and density of the coating are severely reduced, and the overall coating becomes brittle and hard, with significantly decreased erosion resistance and wear resistance, failing to meet practical application requirements. To reduce the low-temperature curing rate of metal oxides, some researchers have prepared slow-release low-temperature curing agents using methods such as silica-coated zinc oxide and alumina-coated zinc oxide. Although this lowers the curing temperature, the cured coating material still has poor mechanical properties and is prone to defects such as microcracks. Therefore, based on the problems existing in the current technology, there is an urgent need to develop a phosphate composite coating material with a low curing temperature and excellent adhesion, flexibility, high-temperature resistance, and corrosion protection after curing. Summary of the Invention

[0004] In order to overcome the shortcomings and deficiencies of the prior art, the present invention aims to provide a high-temperature corrosion resistant protective coating that cures at low temperatures with an alcohol amine. This coating can be completely cured at low temperatures, with a curing temperature as low as 80°C. Moreover, the preparation method of the coating is simple, and the resulting coating material has stable and reliable performance, excellent high-temperature resistance, comprehensive mechanical properties, and corrosion protection performance.

[0005] The technical solution of the present invention is a high-temperature corrosion resistant protective coating that cures at low temperature with an alcohol amine, comprising the following components in weight percentage: 20-35% aluminum dihydrogen phosphate or chromium-doped aluminum dihydrogen phosphate, 2-5% chromium trioxide reduced from aluminum powder, 5-10% low molecular weight alcohol amine compound, 0.5-1% wetting and dispersing agent, 0.5-1% defoamer, 10-20% pretreated flake aluminum powder, 30-50% pretreated spherical aluminum powder, and the balance being deionized water.

[0006] The preparation method of the alkanolamine low-temperature curing inorganic aluminum coating is as follows: aluminum dihydrogen phosphate or chromium-doped aluminum dihydrogen phosphate, chromium trioxide reduced by aluminum powder, low molecular weight alkanolamine compound, wetting and dispersing agent, defoamer, pretreated flake aluminum powder, pretreated spherical aluminum powder, and deionized water are mechanically stirred and mixed to obtain a mixed liquid slurry. The slurry is then sheared and dispersed at high speed on a high-speed shear disperser to obtain a uniform alkanolamine low-temperature curing high-temperature corrosion resistant protective coating.

[0007] The aluminum dihydrogen phosphate or chromium-doped aluminum dihydrogen phosphate is diluted with deionized water to a solid content of 58-63%.

[0008] The method for preparing aluminum dihydrogen phosphate is as follows: Alumina powder with a molar ratio of 1:(2~4) is mixed with 85% phosphoric acid, and the mixture is refluxed at 100~120℃ for 0.5~1.5 h, then naturally cooled to room temperature. The method for preparing chromium-doped aluminum dihydrogen phosphate is as follows: Alumina powder with a molar ratio of 1:(2~4) is mixed with 85% phosphoric acid, and then 10 wt% of chromium oxide powder (based on the total alumina content) is added. After thorough dissolution by mechanical stirring, the mixture is refluxed at 100~120℃ for 0.5~1.5 h, then naturally cooled to room temperature.

[0009] The process of reducing chromium trioxide with aluminum powder involves completely dissolving chromium trioxide in deionized water, adding spherical aluminum powder, mechanically stirring for 25-35 minutes, and then allowing it to naturally return to room temperature. The amount of spherical aluminum powder added is 10-15% of the total mass of chromium trioxide.

[0010] The low molecular weight alcohol amine compound is one or a mixture of two of monoethanolamine, diethanolamine, diisopropanolamine, and N-methyldiethanolamine.

[0011] The wetting and dispersing agent is BYK-333 or BYK-192.

[0012] The defoamer is one or more of BYK019, BYK028, and BYK021.

[0013] The pretreated flake aluminum powder has a size of 5-8 micrometers; the pretreated spherical aluminum powder has a size of 1-2 micrometer aluminum powder and 3-5 micrometer aluminum powder, and the mass ratio of 1-2 micrometer aluminum powder to 3-5 micrometer aluminum powder is (1:2) to (1:5); The pretreatment method for the flake aluminum powder and spherical aluminum powder is to uniformly disperse the flake aluminum powder or spherical aluminum powder in deionized water, then slowly add aluminum dihydrogen phosphate or chromium-doped aluminum dihydrogen phosphate, and mechanically stir the reaction for 40 to 60 minutes to obtain a uniform slurry mixture. The mass ratio of flake aluminum powder or spherical aluminum powder to aluminum dihydrogen phosphate or chromium-doped aluminum dihydrogen phosphate resin is (15~20):1.

[0014] The high-speed shearing rate of the mixed liquid slurry is 10,000~15,000 r / min, and the shearing time is 2.0~2.5 min.

[0015] The coating is fully cured at 80±10℃ for 2-4 hours, followed by a further increase in temperature to 190℃±10℃ and holding for 0.5-1.5 hours, or directly held at 80℃±10℃ for 8-12 hours.

[0016] The present invention has the following beneficial effects: The high-temperature corrosion-resistant protective coating with alkanolamine low-temperature curing of the present invention uses aluminum dihydrogen phosphate or chromium-doped aluminum dihydrogen phosphate, which has good high-temperature resistance, as a binder, and has good bonding strength on metal or alloy substrates. Passivated pre-treated flake and spherical aluminum powder are used as sacrificial corrosion-resistant fillers. The passivation pre-treatment process effectively inhibits the redox reaction between the aluminum powder filler and the phosphate resin, improving the room temperature storage stability of the coating. By selecting alkanolamine as a low-temperature curing agent, the reactive sites of the amino and hydroxyl groups in the alkanolamine molecule are fully utilized to achieve the bridging effect between the amino and hydroxyl groups and the phosphate molecules, realizing the intramolecular dehydration condensation reaction at low temperature and forming a macromolecular network structure. This not only ensures complete dehydration condensation reaction at low temperature and complete curing of the coating, but also results in a slow dehydration reaction rate between the alkanolamine molecules and the phosphate resin, leading to a dense coating structure and strong adhesion to the substrate after curing. Furthermore, alkanolamine can act as a surfactant during the coating process, promoting self-leveling of the coating and making the cured coating surface more uniform and smooth.

[0017] The alkanolamine low-temperature curing high-temperature corrosion resistant protective coating provided by the present invention not only has the characteristics of low-temperature curing, but also exhibits excellent comprehensive mechanical properties, high-temperature resistance and corrosion protection performance after curing.

[0018] The preparation process of the low-temperature curing alkanolamine-based high-temperature corrosion resistant protective coating of this invention is simple, has a short production cycle, and is highly operable, making it very suitable for large-scale production and engineering applications in the later stages. Attached Figure Description

[0019] Figure 1 The cross-sectional morphology of the high-temperature corrosion resistant protective coating prepared in Example 1; Figure 2 The adhesion test results are for the high-temperature corrosion resistant protective coating prepared in Example 1; Figure 3 The adhesion test results of the high-temperature corrosion resistant protective coating prepared in Example 2 after being kept at 600°C for 10 h; Figure 4 The morphology of the high-temperature corrosion resistant protective coating prepared in Example 2 after a 400-h neutral salt spray test. Detailed Implementation

[0020] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific conditions and test methods not explicitly described in the following embodiments are generally performed under conventional conditions.

[0021] Example 1 Preparation method of aluminum dihydrogen phosphate: Alumina powder with a molar ratio of 1:3 and 85% phosphoric acid are mixed in a three-necked flask, refluxed at 110℃ for 1 h, and then naturally cooled to room temperature. Preparation method of chromium-doped aluminum dihydrogen phosphate: Alumina powder with a molar ratio of 1:3 and 85% phosphoric acid are mixed in a three-necked flask, and then 10 wt% of chromium oxide powder (based on the total alumina content) is added. After thorough dissolution by mechanical stirring, the mixture is refluxed at 110℃ for 1 h, and then naturally cooled to room temperature.

[0022] The process of reducing chromium trioxide with aluminum powder: After completely dissolving chromium trioxide in deionized water, add 10-15% of the total mass of chromium trioxide in spherical aluminum powder, stir mechanically for 0.5 h, and allow it to naturally return to room temperature.

[0023] The pretreated flake aluminum powder has a size of 5-8 micrometers; the pretreated spherical aluminum powder has a size of 1-2 micrometers and 3-5 micrometers, with a mass ratio of 1:3. Pretreatment of flake aluminum powder: Flake aluminum powder was uniformly dispersed in deionized water, and then aluminum dihydrogen phosphate was slowly added. After mechanical stirring for 1 hour, a uniform slurry mixture was obtained. The mass ratio of flake aluminum powder to aluminum dihydrogen phosphate was 18:1.

[0024] Pretreatment of spherical aluminum powder: After uniformly dispersing the spherical aluminum powder in deionized water, aluminum dihydrogen phosphate was slowly added, and the mixture was mechanically stirred for 1 hour to obtain a uniform slurry mixture. The mass ratio of spherical aluminum powder to aluminum dihydrogen phosphate was 18:1.

[0025] Preparation of a high-temperature corrosion resistant protective coating with low-temperature curing of amine: Accurately weigh 20g of chromium-doped aluminum dihydrogen phosphate solution with a solid content of 59%, 3g of chromium trioxide reduced by aluminum powder, 8g of diethanolamine, 0.5g of BYK-192 wetting agent, 0.6g of BYK-019 defoamer, 15g of pretreated flake aluminum powder, and 35g of pretreated spherical aluminum powder. Then add 17.9g of deionized water and shear disperse at 12000r / min for 2 min on a high-speed shear disperser to obtain a uniform coating slurry.

[0026] Preparation process of high-temperature corrosion resistant protective coating with low-temperature curing of alkanolamine: The above-dispersed slurry was sprayed onto the surfaces of tinplate, low-carbon steel, and high-purity 4169 test pieces and parts using compressed air or compressed nitrogen. (The surfaces of low-carbon steel, high-purity 4169 substrates and parts were sandblasted before spraying, and tinplate was polished with 500-grit sandpaper. After sandblasting or polishing, the surfaces were ultrasonically cleaned with acetone). The coating thickness was controlled to be approximately 40 μm by controlling the number of spraying cycles. After the sprayed parts were placed in air for 5-6 hours, they were cured in a forced-air drying oven under the following conditions: constant temperature of 80±10℃ for 3 hours, followed by heating to 190±10℃ and holding at that temperature for 1 hour, and then naturally cooled to room temperature.

[0027] The adhesion grade of the coatings cured on tinplate specimens was tested according to GB / T 9286 standard, and the bending resistance was tested according to GB / T 6742-2007 standard. Simultaneously, the fully cured coatings on tinplate were immersed in boiling water at 100±10℃ for 10 min, and then immersed in No. 4050 synthetic lubricating oil at 204±14℃. The surface morphology was observed, and the adhesion grade was tested according to GB / T 9286 standard. The coatings cured on high-purity 4169 specimens were kept at 600±10℃ in a muffle furnace for 10 h and then naturally cooled to room temperature before the adhesion grade was tested according to GB / T 9286 standard. The coatings cured on low-carbon steel underwent a neutral salt spray test for more than 400 h according to GB / T 10125 standard. The test results are shown in Table 1.

[0028] Example 2 The preparation method of aluminum dihydrogen phosphate, the treatment process of aluminum powder reduction of chromium trioxide, and the pretreatment process of flake aluminum powder and spherical aluminum powder are all the same as in Example 1.

[0029] Preparation of a high-temperature corrosion resistant protective coating with low-temperature curing of amine: Accurately weigh 20g of aluminum dihydrogen phosphate solution with a solid content of 59%, 5g of chromium trioxide reduced by aluminum powder, 8g of diethanolamine, 0.5g of BYK-333 wetting agent, 0.6g of BYK-028 defoamer, 15g of pretreated flake aluminum powder, and 35g of pretreated spherical aluminum powder. Then add 14.9g of deionized water and shear disperse at 12000r / min for 2min on a high-speed shear disperser to obtain a uniform coating slurry.

[0030] The preparation process and performance tests of the low-temperature curing alkanolamine-resistant high-temperature corrosion protective coating are the same as in Example 1, and the test results are shown in Table 1.

[0031] Example 3 The preparation method of aluminum dihydrogen phosphate, the treatment process of aluminum powder reduction of chromium trioxide, and the pretreatment process of flake aluminum powder and spherical aluminum powder are all the same as in Example 1.

[0032] Preparation of a high-temperature corrosion resistant protective coating with low-temperature curing of amine: Accurately weigh 20g of chromium-doped aluminum dihydrogen phosphate solution with a solid content of 59%, 4g of chromium trioxide reduced by aluminum powder, 6g of diisopropanolamine, 0.5g of BYK-192 wetting agent, 0.6g of BYK-019 defoamer, 18g of pretreated aluminum powder, and 33g of pretreated spherical aluminum powder. Then add 17.9g of deionized water and shear disperse at 12000 r / min for 2 min on a high-speed shear disperser to obtain a uniform coating slurry.

[0033] The preparation process of the low-temperature curing alkanolamine-resistant high-temperature corrosion protective coating is the same as in Example 1, but the curing conditions are different from those in Example 1. Specifically, after the sprayed parts are placed in the air for 5 to 6 hours, they are kept at a constant temperature of 80±10℃ in a forced-air drying oven for 10 hours and then naturally cooled to room temperature.

[0034] The test methods for various properties of the prepared coating are the same as those in Example 1, and the test results are shown in Table 1.

[0035] Example 4 The preparation method of aluminum dihydrogen phosphate, the treatment process of aluminum powder reduction of chromium trioxide, and the pretreatment process of flake aluminum powder and spherical aluminum powder are all the same as in Example 1.

[0036] Preparation of a high-temperature corrosion resistant protective coating with low-temperature curing of amine: Accurately weigh 28g of aluminum dihydrogen phosphate solution with a solid content of 59%, 5g of chromium trioxide reduced by aluminum powder, 9g of diethanolamine, 0.5g of BYK-192 wetting agent, 0.6g of BYK-019 defoamer, 17g of pretreated flake aluminum powder, and 30g of pretreated spherical aluminum powder. Then add 9.9g of deionized water and shear disperse at 12000 r / min for 2 min on a high-speed shear disperser to obtain a uniform coating slurry.

[0037] The preparation and performance testing of the low-temperature curing alkanolamine-resistant high-temperature corrosion protective coating were the same as in Example 1, and the test results are shown in Table 1.

[0038] Example 5 The preparation method of aluminum dihydrogen phosphate, the treatment process of aluminum powder reduction of chromium trioxide, and the pretreatment process of flake aluminum powder and spherical aluminum powder are all the same as in Example 1.

[0039] Preparation of a high-temperature corrosion resistant protective coating with low-temperature curing of amine: Accurately weigh 30g of aluminum dihydrogen phosphate solution with a solid content of 59%, 5g of chromium trioxide reduced by aluminum powder, 9g of N-methyldiethanolamine, 0.5g of BYK-333 wetting agent, 0.6g of BYK-021 defoamer, 15g of pretreated flake aluminum powder, and 35g of pretreated spherical aluminum powder. Then add 5.9g of deionized water and shear disperse at 12000 r / min for 2 min on a high-speed shear disperser to obtain a uniform coating slurry.

[0040] The preparation and performance testing of the low-temperature curing alkanolamine-resistant high-temperature corrosion protective coating were the same as in Example 1, and the test results are shown in Table 1.

[0041] Comparative Example 1 The preparation method of aluminum dihydrogen phosphate, the treatment process of aluminum powder reduction of chromium trioxide, and the pretreatment process of flake aluminum powder and spherical aluminum powder are all the same as in Example 1.

[0042] Preparation of a low-temperature curing, high-temperature corrosion resistant protective coating: Accurately weigh 20g of chromium-doped aluminum dihydrogen phosphate solution with a solid content of 59%, 3g of chromium trioxide reduced by aluminum powder, 0.5g of BYK-192 wetting agent, 0.6g of BYK-019 defoamer, 15g of pretreated flake aluminum powder, and 35g of pretreated spherical aluminum powder. Then add 25.9g of deionized water and shear disperse at 12000 r / min for 2 min on a high-speed shear disperser to obtain a uniform coating slurry.

[0043] The preparation and performance testing of the low-temperature curing high-temperature corrosion resistant protective coating are the same as in Example 1. The test results are shown in Table 1.

[0044] Comparative Example 2 Preparation of high-temperature corrosion resistant protective coating with low-temperature curing of alkanolamine: Accurately weigh 20g of chromium-doped aluminum dihydrogen phosphate solution with a solid content of 59%, 3g of chromium trioxide reduced by aluminum powder, 0.5g of BYK-192 wetting agent, 0.6g of BYK-019 defoamer, 15g of pretreated flake aluminum powder, and 35g of pretreated spherical aluminum powder. Then add 25.9g of deionized water and shear disperse at 12000 r / min for 2 min on a high-speed shear disperser to obtain a uniform coating slurry.

[0045] The preparation process of the low-temperature curing alkanolamine-resistant high-temperature corrosion protective coating is the same as that of Comparative Example 1, but the curing conditions are different. Specifically, the coated parts are placed in the air for 5 to 6 hours, then kept at a constant temperature of 80±10℃ in a forced-air drying oven for 10 hours, and then naturally cooled to room temperature.

[0046] The test methods for various properties of the prepared coating are the same as those in Example 1, and the test results are shown in Table 1.

[0047] Comparative studies of the coatings prepared in Examples 1-5 and Comparative Examples 1 and 2, including adhesion, flexural strength, resistance to boiling water and hot oil immersion, high-temperature resistance, and neutral salt spray tests, showed that alkanolamine compounds can significantly reduce the curing temperature of the coating. Because alkanolamine compounds participate in the dehydration condensation reaction between phosphate resin molecules, the coating can achieve complete curing at a lower temperature. In Comparative Examples 1 and 2, due to the absence of alkanolamine compounds, the coatings did not achieve complete curing under either type of curing condition, and all properties of the coatings failed the test (except for high-temperature resistance). In the different examples, the cured coatings achieved an adhesion grade of 0, exhibited excellent flexibility, resistance to boiling water and hot oil, and passed 400 hours of neutral salt spray testing. However, the coatings prepared in the comparative examples achieved an adhesion grade of 0 after the high-temperature performance test. This was mainly because the high-temperature treatment promoted the secondary dehydration condensation reaction of the coating, leading to complete curing.

[0048] In summary, the high-temperature corrosion-resistant protective coating of this invention uses aluminum dihydrogen phosphate or chromium-doped aluminum dihydrogen phosphate as the base resin binder, mixed aluminum powders of different morphologies and sizes as functional fillers, low-molecular-weight organic alcohol amine compounds as low-temperature curing agents, deionized water as the solvent, and wetting and dispersing agents, additives, etc. This corrosion-resistant coating exhibits excellent high-temperature resistance and can be used for extended periods below 600°C. Its complete curing temperature is as low as 80°C, and the cured coating possesses good adhesion, flexibility, and resistance to boiling water and aviation fuel immersion. It solves the problems of high brittleness, poor density, and high curing temperature found in current inorganic phosphate corrosion-resistant coatings, and can be applied to high-temperature corrosion protection fields requiring low-temperature curing.

Claims

1. An alcohol amine low temperature cured high temperature corrosion resistant protective coating characterized in that, The alkanolamine low-temperature curing high-temperature corrosion resistant protective coating is composed of the following components in the indicated mass percentages: 20-35% aluminum dihydrogen phosphate or chromium-doped aluminum dihydrogen phosphate, 2-5% chromium trioxide reduced from aluminum powder, 5-10% low molecular weight alkanolamine compound, 0.5-1% wetting and dispersing agent, 0.5-1% defoamer, 10-20% pretreated flake aluminum powder, 30-50% pretreated spherical aluminum powder, and the balance being deionized water. The reduction of chromium trioxide by aluminum powder is achieved by completely dissolving chromium trioxide in deionized water, adding spherical aluminum powder, mechanically stirring for 25-35 minutes, and then allowing it to naturally return to room temperature; wherein the amount of spherical aluminum powder added is 10-15% of the total mass of chromium trioxide; The preparation method of the alkanolamine low-temperature curing high-temperature corrosion resistant protective coating is as follows: aluminum dihydrogen phosphate or chromium-doped aluminum dihydrogen phosphate, chromium trioxide reduced by aluminum powder, low molecular weight alkanolamine compound, wetting and dispersing agent, defoamer, pretreated flake aluminum powder, pretreated spherical aluminum powder, and deionized water are mechanically stirred and mixed to obtain a mixed liquid slurry. The slurry is then sheared and dispersed at high speed on a high-speed shear disperser to obtain a uniform alkanolamine low-temperature curing high-temperature corrosion resistant protective coating.

2. The alkanolamine low temperature cured high temperature corrosion resistant protective coating of claim 1, wherein, The aluminum dihydrogen phosphate or chromium-doped aluminum dihydrogen phosphate is diluted with deionized water to a solid content of 58-63%.

3. The alkanolamine low temperature cured high temperature corrosion resistant protective coating of claim 1, wherein, The method for preparing aluminum dihydrogen phosphate is as follows: aluminum oxide powder with a molar ratio of 1:(2~4) is mixed with 85% phosphoric acid, and then refluxed at 100~120℃ for 0.5~1.5h, and naturally cooled to room temperature to obtain the product. The preparation method of the chromium-doped aluminum dihydrogen phosphate is as follows: Alumina powder with a molar ratio of 1:(2~4) is mixed with 85% phosphoric acid, and then 10 wt% of chromium oxide powder is added. After the mixture is fully dissolved by mechanical stirring, it is refluxed at 100~120℃ for 0.5~1.5 h and then naturally cooled to room temperature.

4. The alkanolamine low temperature cured high temperature corrosion resistant protective coating of claim 1, wherein, The low molecular weight alcohol amine compound is one or a mixture of two of monoethanolamine, diethanolamine, diisopropanolamine, and N-methyldiethanolamine.

5. The alkanolamine low temperature cured high temperature corrosion resistant protective coating of claim 1, wherein, The wetting and dispersing agent is BYK-333 or BYK-192.

6. The alkanolamine low temperature cured high temperature corrosion resistant protective coating of claim 1, wherein, The defoamer is one or more of BYK019, BYK028, and BYK021.

7. The alkanolamine low temperature cured high temperature corrosion resistant protective coating of claim 1 wherein, The pretreated flake aluminum powder has a size of 5-8 micrometers; the pretreated spherical aluminum powder has a size of 1-2 micrometers and 3-5 micrometers, with a mass ratio of 1:2 to 1:

5. The pretreatment method for the flake aluminum powder and spherical aluminum powder is to uniformly disperse the flake aluminum powder or spherical aluminum powder in deionized water, then slowly add aluminum dihydrogen phosphate or chromium-doped aluminum dihydrogen phosphate, and mechanically stir the reaction for 40 to 60 minutes to obtain a uniform slurry mixture. The mass ratio of flake aluminum powder or spherical aluminum powder to aluminum dihydrogen phosphate or chromium-doped aluminum dihydrogen phosphate resin is (15~20):

1.

8. The alkanolamine low temperature cured high temperature corrosion resistant protective coating of claim 1, wherein, The high-speed shearing rate of the mixed liquid slurry is 10,000~15,000 r / min, and the shearing time is 2.0~2.5 min.

9. The alkanolamine low temperature cured high temperature corrosion resistant protective coating of claim 1, wherein, The coating is fully cured at 80±10℃ for 2-4 hours, then the temperature is increased to 190℃±10℃ and held for 0.5-1.5 hours, or directly held at 80℃±10℃ for 8-12 hours.

Images