Heat-resistant anticorrosive paint for alloy, method of preparation and method of use

Abstract

The application discloses an alloy heat-resistant anticorrosive paint, a preparation method and a use method, and belongs to the technical field of anticorrosive paints. The alloy heat-resistant anticorrosive paint comprises the following components in parts by weight: 25-42 parts of epoxy resin, 18-30 parts of phenolic resin, 10-15 parts of a polycarbonate-rubber-inorganic filler ternary compound, 1-5 parts of a curing agent, 3-5 parts of aluminum hydroxyl oxide, 5-10 parts of flaky mica powder and 30-50 parts of a solvent. The application constructs a brand-new anticorrosive paint system, which can form a tough and dense protective film on the surface of an alloy, effectively insulates corrosion medium, and still has excellent protection efficacy in a harsh environment with variable conditions.

Description

Technical Field

[0001] This invention belongs to the field of anti-corrosion coating technology, specifically a heat-resistant anti-corrosion coating for alloys, its preparation method, and its application method. Background Technology

[0002] Magnesium alloys are lightweight, high-strength, and excellent specific stiffness and specific strength. Their density is only two-thirds that of aluminum and one-quarter that of steel. As the lightest metallic structural material, they are hailed as "the green engineering material with the greatest development and application potential in the century." Magnesium alloys also possess excellent thermal conductivity, electromagnetic shielding, and recyclability, making them promising for applications in the automotive, aerospace, electronics and communications, and medical device industries.

[0003] However, due to its inherent material properties, magnesium alloys exhibit a low electrode potential. Therefore, they are highly susceptible to corrosion in corrosive media. Furthermore, compared to other metals such as aluminum alloys and stainless steel, the corrosion products of magnesium alloys are porous magnesium oxide, which lacks corrosion resistance. This is a significant reason why its application in practical engineering is severely limited. Currently, magnesium alloys still require surface coatings for corrosion protection in engineering applications. Therefore, there is an urgent need to develop a coating material with excellent corrosion resistance. Summary of the Invention

[0004] The purpose of this invention is to provide a heat-resistant and corrosion-resistant coating for alloys, its preparation method, and its application method, so as to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0006] The purpose of this invention is to provide a heat-resistant and corrosion-resistant coating for alloys, comprising the following components in parts by weight:

[0007] The mixture contains 25-42 parts epoxy resin, 18-30 parts phenolic resin, 10-15 parts polycarbonate-rubber-inorganic filler ternary composite, 1-5 parts curing agent, 3-5 parts alumina hydroxyl, 5-10 parts flake mica powder, and 30-50 parts solvent.

[0008] The preparation process of the polycarbonate-rubber-inorganic filler ternary composite is as follows:

[0009] (1) The inorganic filler is ultrasonically dispersed, then a silane coupling agent is added, and the dispersion is continued for 5-10 minutes before drying.

[0010] (2) Soak the rubber granules in an alkaline solution, then take them out, wash them until neutral and dry them, and then add silane coupling agent and mix them evenly;

[0011] (3) Heat the polycarbonate to a molten state, then add the inorganic filler treated in step (1) and the rubber treated in step (2), stir and mix, and then dry to obtain a polycarbonate-rubber-inorganic filler ternary composite.

[0012] Furthermore, it includes the following components in parts by weight:

[0013] The mixture comprises 25-30 parts epoxy resin, 20-25 parts phenolic resin, 10-12 parts polycarbonate-rubber-inorganic filler ternary composite, 1-3 parts curing agent, 3-5 parts hydroxyalumina, 5-8 parts flake mica powder, and 30-40 parts solvent.

[0014] Furthermore, the mass ratio of polycarbonate, inorganic filler and rubber particles is 1:1~1.5:0.5~1.

[0015] Furthermore, the inorganic filler is calcium carbonate particles with a particle size of 0.5~2mm.

[0016] Furthermore, the silane coupling agent is KH550 or KH560.

[0017] Furthermore, the alkaline solution used to soak the rubber particles is a sodium hydroxide solution, and the particle size of the rubber particles is 0.5~1mm.

[0018] Furthermore, the epoxy resin is any one of E20, E44, and E51.

[0019] Furthermore, the solvent is butanol.

[0020] Furthermore, the curing agent is an aromatic amine.

[0021] Furthermore, the curing agent is 650 polyamide curing agent, diethylenetriamine, p-phenylenediamine, 1,3-cyclohexanedimethylamine, etc.

[0022] Furthermore, the particle size of the flaky mica powder is 1~2mm.

[0023] Another object of the present invention is to provide a method for preparing the above-mentioned heat-resistant and corrosion-resistant coating for alloys, as follows:

[0024] Epoxy resin, phenolic resin, aluminum hydroxide and flake mica powder are added to a solvent and stirred until homogeneous. Then, a ternary composite of polycarbonate-rubber-inorganic filler and a curing agent are added and stirred until homogeneous to obtain the final product.

[0025] Another object of the present invention is to provide a method of using the above-mentioned heat-resistant and corrosion-resistant coating for alloys, comprising the following steps:

[0026] S1. Prepare a micro-arc oxidation film on the alloy surface;

[0027] S2. Apply the above alloy to the surface of the micro-arc oxide film layer with heat-resistant and anti-corrosion coating, and let it stand for 20~30 hours to complete the process.

[0028] Furthermore, the alloy is a magnesium alloy.

[0029] Furthermore, the operating conditions for micro-arc oxidation are: temperature 25-30℃, power supply mode dual-pulse, oxidation time 25-30 min, positive final voltage 250V, negative final voltage 80V, and current density 1.5A / dm³. 2 The frequency is 350Hz, and the duty cycle of both the positive and negative pulses is 20%.

[0030] Furthermore, the electrolyte used in micro-arc oxidation is: deionized water as solvent, containing 26.2 g / L calcium acetate, 5.5 g / L sodium hydroxide, 5.2 g / L sodium silicate, and 5 g / L ammonium fluoride.

[0031] The present invention has the following beneficial effects:

[0032] This invention utilizes a ternary composite of epoxy resin, phenolic resin, and polycarbonate-rubber-inorganic filler to create an anti-corrosion coating that forms a tough and dense protective film on the alloy surface, effectively isolating corrosive media and significantly improving the alloy's corrosion resistance. First, epoxy resin and phenolic resin serve as the substrate, adhering to the alloy surface. Then, the isolation system formed by the polycarbonate-rubber-inorganic filler ternary composite effectively slows down the corrosion process. The addition of flake mica powder, to a certain extent, forms a layered-cubic composite structure with the polycarbonate-rubber-inorganic filler, further effectively verifying the corrosion process. The addition of alumina hydroxyaluminate enhances the bonding effect between the resin and the inorganic filler, improving its interlaminar fracture toughness.

[0033] In the ternary composite, polycarbonate is bonded to rubber and inorganic fillers via silane coupling agents. The addition of rubber particles effectively improves the protective performance under harsh environments such as temperature changes and chemical immersion treatments. Furthermore, the rubber particles are soaked in alkali to remove surface impurities, increase surface roughness, and improve dispersion uniformity, enabling them to better form a composite system with polycarbonate and inorganic fillers. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0035] Example 1:

[0036] A heat-resistant and corrosion-resistant coating for alloys, comprising the following components in parts by weight:

[0037] The composition includes 25 parts epoxy resin, 20 parts phenolic resin, 12 parts polycarbonate-rubber-inorganic filler ternary composite, 1 part 1,3-cyclohexanedimethylamine, 5 parts alumina hydroxyl, 8 parts flaky mica powder, and 40 parts butanol.

[0038] The preparation process of the polycarbonate-rubber-inorganic filler ternary composite is as follows:

[0039] (1) Disperse calcium carbonate particles with a particle size of 1.2 mm by ultrasonication for 30 min, then add silane coupling agent KH550, continue dispersing for 10 min, and then take them out and dry them.

[0040] (2) Soak rubber particles with a particle size of 1 mm in sodium hydroxide solution, then take them out, wash them until neutral and dry them, and then add silane coupling agent KH550 and mix them evenly.

[0041] (3) Heat the polycarbonate to a molten state, then add the inorganic filler treated in step (1) and the rubber treated in step (2), stir and mix, dry, and crush it to a particle size of 1.5 mm to obtain a polycarbonate-rubber-inorganic filler ternary composite, wherein the mass ratio of polycarbonate, calcium carbonate particles and rubber particles is 1:1.2:0.5.

[0042] The preparation method of anti-corrosion coating is as follows:

[0043] Epoxy resin, phenolic resin, aluminum hydroxide and flake mica powder are added to a solvent and stirred until homogeneous. Then, a ternary composite of polycarbonate-rubber-inorganic filler and 1,3-cyclohexanedimethylamine are added and stirred until homogeneous to obtain the final product.

[0044] The application method of the above-mentioned anti-corrosion coating is as follows:

[0045] S1. The magnesium alloy substrate undergoes routine treatments such as degreasing and cleaning, followed by micro-arc oxidation. The operating conditions for micro-arc oxidation are: temperature 25-30℃, power mode dual pulse, oxidation time 30 min, positive final voltage 250V, negative final voltage 80V, and current density 1.5A / dm³. 2 The frequency is 350Hz, and the duty cycle of both the positive and negative pulses is 20%.

[0046] The electrolyte used is deionized water as the solvent, containing 26.2 g / L calcium acetate, 5.5 g / L sodium hydroxide, 5.2 g / L sodium silicate, and 5 g / L ammonium fluoride.

[0047] S2. Apply the anti-corrosion coating to the surface of the micro-arc oxidation film layer and let it stand for 20~30 hours to complete the process.

[0048] Example 2:

[0049] A heat-resistant and corrosion-resistant coating for alloys, comprising the following components in parts by weight:

[0050] The composition includes 30 parts epoxy resin, 25 parts phenolic resin, 10 parts polycarbonate-rubber-inorganic filler ternary composite, 3 parts 1,3-cyclohexanedimethylamine, 5 parts aluminum hydroxide, 8 parts flake mica powder, and 38 parts butanol.

[0051] The preparation process of the polycarbonate-rubber-inorganic filler ternary composite is as follows:

[0052] (1) Disperse calcium carbonate particles with a particle size of 1 mm by ultrasonication for 30 min, then add silane coupling agent KH550, continue dispersing for 10 min, and then take them out and dry.

[0053] (2) Soak rubber particles with a particle size of 0.8 mm in sodium hydroxide solution, then take them out, wash them until neutral and dry them, and then add silane coupling agent KH550 and mix them evenly;

[0054] (3) Heat the polycarbonate to a molten state, then add the inorganic filler treated in step (1) and the rubber treated in step (2), stir and mix, dry, and crush it to a particle size of 1.8 mm to obtain a polycarbonate-rubber-inorganic filler ternary composite, wherein the mass ratio of polycarbonate, calcium carbonate particles and rubber particles is 1:1:1.

[0055] The preparation method of anti-corrosion coating is as follows:

[0056] Epoxy resin, phenolic resin, aluminum hydroxide and flake mica powder are added to a solvent and stirred until homogeneous. Then, a ternary composite of polycarbonate-rubber-inorganic filler and 1,3-cyclohexanedimethylamine are added and stirred until homogeneous to obtain the final product.

[0057] The application method of the above-mentioned anti-corrosion coating is as follows:

[0058] S1. The magnesium alloy substrate undergoes routine treatments such as degreasing and cleaning, followed by micro-arc oxidation. The operating conditions for micro-arc oxidation are: temperature 25-30℃, power mode dual pulse, oxidation time 30 min, positive final voltage 250V, negative final voltage 80V, and current density 1.5A / dm³. 2 The frequency is 350Hz, and the duty cycle of both the positive and negative pulses is 20%.

[0059] The electrolyte used is deionized water as the solvent, containing 26.2 g / L calcium acetate, 5.5 g / L sodium hydroxide, 5.2 g / L sodium silicate, and 5 g / L ammonium fluoride.

[0060] S2. Apply the anti-corrosion coating to the surface of the micro-arc oxidation film layer and let it stand for 20~30 hours to complete the process.

[0061] Example 3:

[0062] A heat-resistant and corrosion-resistant coating for alloys, comprising the following components in parts by weight:

[0063] The composition includes 28 parts epoxy resin, 22 parts phenolic resin, 11 parts polycarbonate-rubber-inorganic filler ternary composite, 1 part 1,3-cyclohexanedimethylamine, 5 parts alumina hydroxyl, 6 parts flaky mica powder, and 30 parts butanol.

[0064] The preparation process of the polycarbonate-rubber-inorganic filler ternary composite is as follows:

[0065] (1) Disperse calcium carbonate particles with a particle size of 1.5 mm by ultrasonication for 30 min, then add silane coupling agent KH550, continue dispersing for 10 min, and then take them out and dry.

[0066] (2) Soak rubber particles with a particle size of 1 mm in sodium hydroxide solution, then take them out, wash them until neutral and dry them, and then add silane coupling agent KH550 and mix them evenly.

[0067] (3) Heat the polycarbonate to a molten state, then add the inorganic filler treated in step (1) and the rubber treated in step (2), stir and mix, dry, and crush it to a particle size of 1.5 mm to obtain a polycarbonate-rubber-inorganic filler ternary composite, wherein the mass ratio of polycarbonate, calcium carbonate particles and rubber particles is 1:1.2:1.

[0068] The preparation method of anti-corrosion coating is as follows:

[0069] Epoxy resin, phenolic resin, aluminum hydroxide and flake mica powder are added to a solvent and stirred until homogeneous. Then, a ternary composite of polycarbonate-rubber-inorganic filler and 1,3-cyclohexanedimethylamine are added and stirred until homogeneous to obtain the final product.

[0070] The application method of the above-mentioned anti-corrosion coating is as follows:

[0071] S1. The magnesium alloy substrate undergoes routine treatments such as degreasing and cleaning, followed by micro-arc oxidation. The operating conditions for micro-arc oxidation are: temperature 25-30℃, power mode dual pulse, oxidation time 30 min, positive final voltage 250V, negative final voltage 80V, and current density 1.5A / dm³. 2The frequency is 350Hz, and the duty cycle of both the positive and negative pulses is 20%.

[0072] The electrolyte used is deionized water as the solvent, containing 26.2 g / L calcium acetate, 5.5 g / L sodium hydroxide, 5.2 g / L sodium silicate, and 5 g / L ammonium fluoride.

[0073] S2. Apply the anti-corrosion coating to the surface of the micro-arc oxidation film layer and let it stand for 20~30 hours to complete the process.

[0074] Comparative Example 1:

[0075] An anti-corrosion coating comprising the following components in parts by weight:

[0076] The composition includes 25 parts epoxy resin, 20 parts phenolic resin, 10 parts polycarbonate, 12 parts calcium carbonate granules, 5 parts rubber granules, 1 part curing agent, 5 parts aluminum hydroxide, 8 parts flake mica powder, and 40 parts butanol.

[0077] Comparative Example 2:

[0078] A heat-resistant and corrosion-resistant coating comprising the following components in parts by weight:

[0079] The mixture consists of 25 parts epoxy resin, 20 parts phenolic resin, 12 parts polycarbonate-inorganic filler composite, 1 part curing agent, 5 parts hydroxyalumina, 8 parts flake mica powder, and 40 parts butanol.

[0080] The preparation process of the polycarbonate-inorganic filler composite is as follows:

[0081] (1) Disperse calcium carbonate particles with a particle size of 1.2 mm by ultrasonication for 30 min, then add silane coupling agent KH550, continue dispersing for 10 min, and then take them out and dry them.

[0082] (2) Heat the polycarbonate to a molten state, then add the inorganic filler treated in step (1), stir and mix, dry, and crush it to a particle size of 1.5 mm to obtain a polycarbonate-inorganic filler composite, wherein the mass ratio of polycarbonate to calcium carbonate particles is 1:1.2.

[0083] Comparative Example 3:

[0084] Compared to Example 1, no flake mica powder was added, and the rest of the process remained the same as in Example 1.

[0085] Experimental example:

[0086] 1. Corrosion test

[0087] As described in Examples 1-3 and Comparative Examples 1-3, after applying an anti-corrosion coating to the surface of the magnesium alloy substrate AZ31B, a corrosion resistance test was conducted according to ISO 9227:2017 standard. The specific process is as follows:

[0088] The sample was fixed, and the pH of the 10% sodium chloride was adjusted to 3 with 3% hydrochloric acid to prepare a saline solution. The solution was sprayed onto the sample using a spray device at a spray rate of 20 mL / s, a spray frequency of 60 min / time, and each spray lasted for 20 seconds. The spraying was continued for 168 h. The corrosion of the sample was observed at 48 h, 96 h, and 168 h. The results are shown in Table 1.

[0089] Table 1 Corrosion Resistance Test Results

[0090]

[0091] 2. Moisture and heat resistance test

[0092] The samples prepared in Test 1 were placed in a drying oven and heated at 120°C for 3600 s. After heating, the samples were immersed in natural seawater for 3600 s. Following immersion, the samples were washed in anhydrous ethanol to remove the surface seawater and then placed back into the drying oven for heating at 120°C for 3600 s. This process was repeated four times for all samples. The corrosion resistance after 168 h was then measured using the same method as in Test 1. The results are shown in Table 2.

[0093] Table 2 Corrosion Resistance Test

[0094]

[0095] According to the test results in Table 1, under progressive corrosion conditions, the coatings prepared in Examples 1-3 of this invention can all provide protection for the alloy. However, the protective effects of the coatings prepared in Comparative Examples 1 and 2 are inferior to those in Examples 1-3, with Comparative Example 1 showing the worst protective effect. Even after undergoing relatively harsh damp heat treatment, the coatings prepared in Examples 1-3 still exhibit excellent protective effects, while the protective effects of the coatings prepared in Comparative Examples 1-3 are significantly reduced. This further demonstrates the excellent corrosion resistance of the coatings prepared in this invention, particularly their protective efficacy under harsh environments.

[0096] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A heat-resistant anticorrosive paint for alloys, characterized by, The components include the following weight parts: epoxy resin 25~30 parts, phenolic resin 20~25 parts, polycarbonate-rubber-inorganic filler ternary composite 10~12 parts, curing agent 1~3 parts, hydroxyl aluminum oxide 3~5 parts, flaky mica powder 5~8 parts and solvent 30~40 parts. The preparation process of the polycarbonate-rubber-inorganic filler ternary composite is as follows: (1) ultrasonic dispersion is performed on the inorganic filler, then silane coupling agent is added, and after 5~10 min of continuous dispersion, it is taken out and dried; (2) the rubber particles are soaked in lye, then taken out, washed to neutral and dried, and then the silane coupling agent is added and uniformly mixed; (3) the polycarbonate is heated to a molten state, then the inorganic filler treated in step (1) and the rubber treated in step (2) are added, and after stirring and mixing, it is dried to obtain a polycarbonate-rubber-inorganic filler ternary composite.

2. The heat-resistant anticorrosive paint for alloys according to claim 1, characterized by The components include the following weight parts: epoxy resin 25~30 parts, phenolic resin 20~25 parts, polycarbonate-rubber-inorganic filler ternary composite 10~12 parts, curing agent 1~3 parts, hydroxyl aluminum oxide 3~5 parts, flaky mica powder 5~8 parts and solvent 30~40 parts.

3. The heat resistant anticorrosive paint for alloy according to claim 1, characterized by The mass ratio of polycarbonate, inorganic filler and rubber particles is 1:1~1.5:0.5~1.

4. The heat-resistant anticorrosive paint for alloys according to claim 1 or 3, characterized by, The inorganic filler is calcium carbonate particles, and the particle size is 0.5~2 mm.

5. The heat-resistant anticorrosive paint for alloys according to claim 1 or 3, characterized by, The silane coupling agent is kh550 or kh560.

6. The heat-resistant anticorrosive paint for alloys according to claim 1 or 3, characterized by, The lye for soaking the rubber particles is sodium hydroxide solution, and the particle size of the rubber particles is 0.5~1 mm.

7. The heat-resistant anticorrosive paint for alloys according to claim 1 or 2, characterized by, The solvent is butanol.

8. The heat-resistant anticorrosive paint for alloys according to claim 1 or 2, characterized by, The curing agent is aromatic amine.

9. A method of preparing a heat-resistant anticorrosive coating for an alloy as claimed in any one of claims 1 to 8, characterized by, The epoxy resin, phenolic resin, hydroxyl aluminum oxide and flaky mica powder are added to the solvent and stirred and uniformly mixed, then the polycarbonate-rubber-inorganic filler ternary composite and the curing agent are added and stirred and uniformly mixed to obtain the alloy.

10. A method of using a heat-resistant anticorrosive coating for an alloy as claimed in any one of claims 1 to 8, characterized in that, The steps include: S1, preparing a micro-arc oxidation film layer on the surface of the alloy; S2, coating the alloy with the heat-resistant anticorrosive paint according to any one of claims 1~8 on the surface of the micro-arc oxidation film layer, and standing for 20~30 h to complete.

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