Self-repairing / corrosion early-warning dual-function coating based on corrosion cathode and anode micro-area environmental response release
By using nanocontainers loaded with corrosion inhibitors and fluorescent agents in the coating, and utilizing the release response of mesoporous silica nanocontainers under different pH conditions, the problem of corrosion inhibitors and fluorescent agents being difficult to accurately act on the corrosive micro-regions in the coating is solved, achieving long-term protection and highly sensitive corrosion early warning.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTHWEST JIAOTONG UNIV
- Filing Date
- 2026-03-06
- Publication Date
- 2026-05-12
AI Technical Summary
In existing technologies, when corrosion inhibitors and fluorescent agents are compounded in coatings, it is difficult to simultaneously and accurately act on the anodic and cathodic micro-regions of corrosion, resulting in low corrosion inhibition efficiency, poor corrosion early warning effect, and short coating protection life.
A corrosion cathode micro-region response nanocontainer A loaded with corrosion inhibitor A and a corrosion anode micro-region response nanocontainer B loaded with fluorescent agent B were used. The mesoporous silica nanocontainers responded to release the corrosion inhibitor and fluorescent agent under different pH conditions, achieving controlled release in the corrosion anode and cathode regions, forming a precipitate film and changing the fluorescence signal.
It achieves long-term protection and corrosion early warning for metal substrates, and improves the protective life of the coating and the sensitivity of corrosion early warning.
Smart Images
Figure CN122011884A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of functional protective coating technology, and in particular to a dual-functional coating that is self-healing and corrosion early warning based on the environmental response release of corrosion anodic and corrosive micro-regions. Background Technology
[0002] Organic coatings passively protect metallic materials by isolating them from corrosive media, making them the most effective, economical, and widely used corrosion protection method. The addition of corrosion inhibitors further endows the coating with active protective properties, making it one of the most widely used methods in corrosion protection technology. Research on corrosion inhibitors has found that the combination of corrosion inhibitors has far superior corrosion inhibition performance compared to single inhibitors, particularly between organic inhibitors (2-MBT, BTA, SAL, etc.) and inorganic inhibitors (Ce...). 3+ Ce 4+ La 3+ Both inorganic and organic corrosion inhibitors (such as sodium silicate) and their combinations can exhibit synergistic protective effects. For example, inorganic corrosion inhibitors like Zn... 2+ With Ce 3+ / Ce 4+ As cathodic corrosion inhibitors, they precipitate to form a film in the cathodic corrosion zone, while organic corrosion inhibitors (BTA, 2-MBT, etc.) generally adsorb to form a film in the anodic corrosion zone, thus synergistically inhibiting corrosion. Compared to single corrosion inhibitors, the combination of adsorbed anodic corrosion inhibitors and precipitated cathodic corrosion inhibitors exhibits superior corrosion inhibition performance. Furthermore, the selective deposition of inorganic corrosion inhibitors on intermetallic compounds and the formation of organic films by organic corrosion inhibitors on the metal substrate are considered the most feasible mechanisms for the synergistic effect of these compounds. Corrosion early warning refers to the use of fluorescent agents or chromogenic agents interacting with corrosion products or changes in pH value in micro-areas caused by corrosion to induce fluorescence or color change phenomena, which are used to assess the corrosion status of the base material.
[0003] Studies have found that directly applying different corrosion inhibitors in combination to coatings, or directly applying corrosion inhibitors and fluorescent agents to coatings, has unavoidable drawbacks. For example, corrosion inhibitors and fluorescent agents may chemically interact with the coating, leading to subsequent coating degradation and corrosion inhibitor deactivation. Encapsulating corrosion inhibitors or fluorescent agents in inert nanocontainers can isolate the corrosion inhibitor or fluorescent agent components from the coating substrate and achieve controlled release, thus providing long-term protection. However, existing single nanocontainers can only target the anodic corrosion (M → M) 3+ + 3e, M 3+ + 3H₂O→ M(OH)₃+ 3H + ) or cathode (3H2O + O2→3OH) The controlled release of a local microenvironment in the coating makes it difficult for compound corrosion inhibitors or fluorescent agents to act precisely on the anodic and cathodic micro-regions of corrosion at the same time, thereby reducing their corrosion inhibition efficiency and significantly affecting the corrosion protection life of the coating. At the same time, there are problems such as poor corrosion early warning and insufficient sensitivity. Summary of the Invention
[0004] To address the problems of insufficient long-term protective performance, poor corrosion early warning function, and insufficient sensitivity of traditional waterborne epoxy resin protective coatings, this invention provides a self-healing / corrosion early warning dual-function coating based on the environmental response release of corrosion anodic and corrosive micro-regions.
[0005] The self-healing / corrosion early warning dual-function coating provided by this invention, based on the environmental response release of corrosion cathode and anode micro-area, includes a nano-container A for corrosion cathode micro-area response loaded with corrosion inhibitor A and a nano-container B for corrosion anode micro-area response loaded with corrosion inhibitor B or fluorescent agent.
[0006] The coating is prepared as follows: Nanocontainers A and B are added to deionized water, followed by epoxy resin and curing agent. The mixture is stirred at high speed to obtain a composite epoxy resin coating. After being applied to a metal substrate and cured, a coating with dual functions of self-healing and corrosion warning is obtained.
[0007] The method for preparing the nanocontainer A is as follows: S1. Dissolve hexadecyltrimethylammonium bromide in water to adjust the pH of the solution to 11.5~12.5, heat to 70-90℃ and keep at a constant temperature for 20~80 min, then add tetraethyl orthosilicate dropwise and stir vigorously for 1~3 h. After cooling, centrifuge to separate the product. Disperse the product obtained by centrifugation in a hydrochloric acid / ethanol mixed solution, stir and centrifuge, and repeat the washing 2~3 times to obtain mSiO2 nanomaterials.
[0008] Preferably, the concentration of hexadecyltrimethylammonium bromide in the reaction solution is 1.5~2.5 mg / mL, and the concentration of tetraethyl orthosilicate is 0.02~0.06 mol / L.
[0009] S2. Disperse mSiO2 nanomaterials in anhydrous ethanol, then add 3-[2-(2-aminoethylamine)ethylamine]propyltrimethoxysilane to form a mixed solution. Heat the mixed solution to 100-120℃ and reflux for 5-7 h. Finally, centrifuge and wash to obtain... f -mSiO2 nanomaterials. Preferably, the concentration of 3-[2-(2-aminoethylamine)ethylamine]propyltrimethoxysilane in the mixed solution is 0.40~1 mol / L.
[0010] S3, will f-mSiO2 nanomaterials were dispersed in an aqueous or ethanol solution containing corrosion inhibitor A. The suspension was placed under vacuum for more than 2 hours, followed by centrifugation to obtain the corrosion inhibitor-loaded material. f -mSiO2 nanocomposite material, namely nanocontainer A.
[0011] The corrosion inhibitor A is an inorganic corrosion inhibitor, preferably an inorganic salt containing cerium ions.
[0012] The corrosion inhibitor B is an organic corrosion inhibitor, preferably BTA or 2-MBT.
[0013] The fluorescent agent is selected from any one of 8-hydroxyquinoline, 8-hydroxyquinoline-5-sulfonic acid, rhodamine B and its derivative FD1.
[0014] The method for preparing the nanocontainer B is as follows: 2-Methylimidazole and a fluorescent agent were added to methanol to form solution A; zinc nitrate hexahydrate was added to another portion of methanol to form solution B; solution B was slowly added to solution A, and the reaction was stirred at room temperature for 20-24 hours. The product collected by centrifugation was the nanocontainer B.
[0015] The fluorescent agent is preferably 8-hydroxyquinoline or 8-hydroxyquinoline-5-sulfonic acid, which has both corrosion warning and corrosion inhibition functions, and can simultaneously exert corrosion inhibition and fluorescent warning effects. Among them, 8-hydroxyquinoline-5-sulfonic acid has higher water solubility and is more suitable for protection in aqueous corrosive media.
[0016] In this coating, the preferred mass ratio of nanocontainer A to nanocontainer B is 1:1 to 4:1, and the total mass of the two nanocontainers is 0.3 to 1.0 wt.% of the epoxy resin added.
[0017] Compared with the prior art, the advantages of the present invention are: (1) The present invention modifies mesoporous silica with triaminosilane ( f -mSiO2) serves as a nanocontainer, utilizing its mesoporous structure to encapsulate common metal corrosion inhibitors, while simultaneously f The surface of the -mSiO2 nanocontainer contains aminosilane molecules, which act as "nanogates". The opening and closing of the "nanogates" are achieved by utilizing the different charge states of the amino groups under different pH conditions. f -mSiO2 does not crack under acidic and neutral conditions, ensuring that the nanocontainer does not undergo premature spontaneous diffusion release under these conditions. When the coating is damaged or undergoes localized corrosion, in the metal corrosion galvanic cell, the corrosion cathode region gains electrons, resulting in oxygen absorption corrosion and the generation of OH-. (O2 + 2H2O + 4e → 4OH) This causes an increase in pH value, under alkaline conditions.f -mSiO2 will break down in response to pH stimulation, triggering the release of corrosion inhibitors. The released corrosion inhibitors will form a precipitation film on the metal surface, isolating the corrosive medium from the corrosive effect on the metal substrate, thereby achieving long-term protection of the metal substrate.
[0018] (2) In this invention, ZIF-8 is used as a carrier for fluorescent agents such as 8-hydroxyquinoline (8-HQ) and its derivative 8-hydroxyquinoline-5-sulfonic acid (8-HQS), and Rhodamine B and its derivative FD1, achieving loading of fluorescent agents through its own porous structure. When the protective effect of the coating fails, the corrosion anodic region loses electrons, which, combined with the hydrolysis of metal ions, causes a local decrease in pH and the enrichment of metal ions (M → M). 3+ + 3e, M 3+ + 3H₂O → M(OH)₃ + 3H + ZIF-8's acid and high-valence metal ion sensitivity can trigger the release of fluorescent agents. These fluorescent agents interact with the metal surface, causing a change in the fluorescence signal and providing early warning of corrosion. Among them, 8-hydroxyquinoline (8-HQ) and its derivatives (such as 8-HQS) possess both corrosion inhibition and fluorescence properties, simultaneously providing both. When combined with other corrosion inhibitors, they often exhibit superior protective effects compared to a single inhibitor, i.e., "1+1>2". The hydroxyl groups in the 8-HQ or 8-HQS structure react with Al... 3+ When metal ions undergo coordination reactions to form metal chelates, they effectively block the corrosion of the metal matrix by the corrosive medium. Derivatives such as 8-HQ and 8-HQS are typical photoinduced electron transfer probes; the molecules themselves do not emit light, but react with Al... 3+ Chelation transforms the molecule into a rigid planar structure, significantly reducing the probability of non-radiative transitions when the molecule returns from the excited state to the ground state, thus exhibiting fluorescence. The fluorescent agent 8-hydroxyquinoline and its derivatives (Rhodamine B molecules have conjugation) π In electronic systems, metal ions form coordination complexes with the functional groups (such as carboxyl and amino groups) of Rhodamine B, leading to energy or electron transfer. This causes the excited-state energy to dissipate non-radiatively, resulting in decreased fluorescence intensity and fluorescence quenching. FD1, on the other hand, is a typical intramolecular charge-transfer compound with a conjugated structure. Under acidic conditions, FD1 hydrolyzes to Rhodamine B hydrazide (RBH), which changes from a non-fluorescent closed-ring structure to a strongly fluorescent open-ring structure. Furthermore, if an organic corrosion inhibitor is loaded into the nanocontainer B, the inhibitor, after being released from the anodic corrosion region, adsorbs onto the metal substrate to form a film, thereby synergistically inhibiting corrosion.
[0019] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description
[0020] Figure 1 This is a SEM image of nanocontainer A prepared in Example 1.
[0021] Figure 2 This is a SEM image of nanocontainer B prepared in Example 1. Figure 3 These are the salt spray test results of the coatings in Example 1 and Comparative Examples 1-4.
[0022] Figure 4 The figures show the results of corrosion inhibitor release experiments under different pH conditions for nanocontainer A prepared in Example 1 and nanocontainer C prepared in Comparative Example 5.
[0023] Figure 5 This is an optical morphology image of NaCl solutions containing different corrosion inhibitor components after being held on 2024 aluminum alloy for 24 hours. Detailed Implementation
[0024] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.
[0025] Example 1 A self-healing / corrosion early warning dual-functional coating based on the environmental response release of corrosion anodic and corrosive micro-regions is prepared as follows: S1. Preparation of nanocontainer A for corrosion cathode micro-area response with loaded corrosion inhibitor A: (1) Add 500 mg hexadecyltrimethylammonium bromide to 250 mL of deionized water, adjust the pH of the solution to 12, heat to 80 °C and keep warm for 30 min, then add 2.5 mL tetraethyl orthosilicate and stir vigorously for 2 h. After cooling, disperse the centrifuged product in a hydrochloric acid / ethanol mixed solution (15 mL hydrochloric acid and 150 mL ethanol are mixed), stir and centrifuge to separate for washing. Repeat the washing step 2 to 3 times to obtain mSiO2 nanomaterials. (2) Disperse the obtained mSiO2 nanomaterials in 100 mL of anhydrous ethanol, add 10 mL of 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane, reflux at 110 °C for 5.5 h, centrifuge and wash to obtain the modified mSiO2, i.e. f -mSiO2 nanomaterials. (3) Prepared f -mSiO2 nanomaterials were dispersed in an aqueous solution containing cerium nitrate (cerium nitrate concentration of 2.5 mg / mL). To accelerate the loading of the corrosion inhibitor, the suspension was placed in a vacuum environment for more than 2 hours, and centrifugation was performed to obtain the loaded Ce. 3+ of f -mSiO2 nanocomposites (abbreviated as Ce@) f -mSiO2), which is the nanocontainer A.
[0026] S2. Preparation of nanocontainer B with a corrosion anodic micro-region response loaded with fluorescent agent: 90 mmol of 2-methylimidazole and 0.5 mmol of 8-HQS were added to 60 mL of methanol to form solution A; 9 mmol of zinc nitrate hexahydrate was added to 60 mL of methanol to form solution B; solution B was slowly added to solution A, and the reaction was stirred at room temperature for 24 hours. The product was collected by centrifugation as 8-HQS@ZIF-8, which is nanocontainer B.
[0027] S3. Preparation of a self-healing / corrosion warning dual-function coating: Nanocontainer A and nanocontainer B are added to 30mL of deionized water at a mass ratio of 3:1. Then, 10g of epoxy resin and 20g of curing agent are quickly added and stirred at high speed to obtain a composite epoxy resin coating. The total amount of nanofiller added accounts for 0.4 wt.% of the epoxy resin. After the composite epoxy resin coating is applied to the surface of the metal sheet and cured, a self-healing / corrosion warning dual-function coating (referred to as coating E) is obtained.
[0028] Figure 1 This is a SEM image of the nanocontainer A prepared in step S1. In the image, a, b, and c are SEM images at different magnifications. Figure 1 As shown, Ce@ can be clearly observed at different magnifications using a transmission electron microscope. f- mSiO2 exhibits a typical mesoporous structure, and corrosion inhibitors can be loaded inside the mesoporous channels.
[0029] Figure 2 This is a SEM image of the nanocontainer B prepared in step S2. From... Figure 2 It can be seen that the synthesized 8-HQS@ZIF-8 has a rhombic polyhedral structure, and according to the EDS energy spectrum and elemental distribution diagram, 8-HQS@ZIF-8 mainly contains C, O, N and Zn, and the elements are uniformly distributed.
[0030] Comparative Example 1 30mL of deionized water, 10g of epoxy resin and 20g of curing agent are rapidly mixed and stirred at high speed to obtain pure epoxy resin coating. After being applied to the surface of a metal sheet and cured, pure epoxy resin coating (referred to as coating A) is obtained.
[0031] Comparative Example 2 8-HQS and cerium nitrate were added separately to 15 mL of deionized water and stirred until homogeneous. This mixture was then rapidly mixed with 10 g of epoxy resin and 20 g of curing agent, and stirred at high speed to obtain an epoxy resin coating. This coating was then applied to a metal sheet and cured to obtain an epoxy resin coating layer (referred to as Coating B). The amount of 8-HQS added was 0.1 wt.% of the epoxy resin, and the amount of cerium nitrate added was 0.3 wt.% of the epoxy resin.
[0032] Comparative Example 3 The nanocontainer B prepared in Example 1 was added to 30 mL of deionized water, and then 10 g of epoxy resin and 20 g of curing agent were quickly added. The mixture was stirred at high speed to obtain an epoxy resin coating. The amount of nanocontainer B added accounted for 0.4 wt.% of the epoxy resin. After the epoxy resin coating was applied to the surface of the metal sheet and cured, a coating with self-healing / corrosion warning dual functions (referred to as coating C) was obtained.
[0033] Comparative Example 4 The nanocontainer A prepared in Example 1 was added to 30 mL of deionized water, and then 10 g of epoxy resin and 20 g of curing agent were quickly added. The mixture was stirred at high speed to obtain an epoxy resin coating. The amount of nanocontainer A added accounted for 0.4 wt.% of the epoxy resin. After the epoxy resin coating was applied to the surface of the metal sheet and cured, a coating with self-healing / corrosion warning dual functions (referred to as coating D) was obtained.
[0034] Salt spray tests were conducted on the coatings prepared in Example 1 and Comparative Examples 1-4, respectively. The optical morphology of the coating surfaces after different exposure times (0-14 days) is shown in the figure. Figure 3 In the figure, A, B, C, D, and E represent coatings A, B, C, D, and E, respectively. The results show that the pure epoxy resin coating (coating A) exhibited the most severe corrosion. Obvious corrosion spots appeared after one day of salt spray testing, and the number of corrosion spots increased significantly after three days. By the 14-day salt spray test, almost all of the coating was corroded, indicating the extremely poor corrosion resistance of the pure epoxy resin coating. The coating with only a compound corrosion inhibitor, coating B, showed signs of corrosion after one day of salt spray testing. The number of corrosion spots increased significantly by the third day, and after 14 days of salt spray testing, there were numerous corrosion spots covering a large area, indicating very severe corrosion. This demonstrates that directly adding the corrosion inhibitor did not improve the long-term protective effect of the coating. Composite coatings doped with only one type of nanocontainer showed minimal corrosion after one day of salt spray testing, with corrosion worsening after three days. While coating C did not show large corrosion spots, the overall coating turned black, indicating that the corrosive medium had penetrated to the metal substrate surface, resulting in numerous small corrosion spots. The corrosion area expanded after seven days, and overall corrosion intensified on the fourteenth day. Coating D showed filamentous corrosion on the third day, turned black on the surface after seven days, and further deteriorated on the fourteenth day, completely losing its protective function. Comparatively, the corrosion levels of coatings C and D were still weaker than those of coatings A and B, indicating that nanocontainers loaded with a single corrosion inhibitor still possess a certain degree of corrosion protection. The composite epoxy resin coating doped with anodically and anolyte-responsive nanocontainers (coating E) exhibited the best corrosion protection performance. Corrosion spots only began to appear after seven days of salt spray testing, and the number and area of these spots were relatively small. After 14 days, the number and area of corrosion spots increased, resulting in a relatively mild overall corrosion level, indicating the excellent corrosion resistance of coating E.
[0035] Comparative Example 5 Following the method in step S1 of Example 1, step (2) is omitted, and a corrosion inhibitor is loaded onto mSiO2 nanomaterials to obtain nanocontainer C. The specific preparation method is as follows: (1) Add 500 mg of cetyltrimethylammonium bromide to 250 mL of deionized water, adjust the pH of the solution to 12, heat to 80 °C and keep warm for 30 min, then add 2.5 mL of tetraethyl orthosilicate and stir vigorously for 2 h. After cooling, disperse the centrifuged product in a hydrochloric acid / ethanol mixed solution (15 mL of hydrochloric acid and 150 mL of ethanol), stir and centrifuge to separate and wash. Repeat the washing step 2-3 times to obtain mSiO2 nanomaterials. (2) Disperse the mSiO2 nanomaterials in an aqueous solution containing cerium nitrate (cerium nitrate concentration is 2.5 mg / mL). To accelerate the loading of the corrosion inhibitor, place the suspension in a vacuum environment for more than 2 hours, and centrifuge to obtain the loaded Ce. 3+ The mSiO2 nanocomposite material (abbreviated as Ce@mSiO2) is the nanocontainer C.
[0036] The corrosion inhibitor release experiments were conducted using nanocontainer A prepared in Example 1 and nanocontainer C prepared in Comparative Example 5 under different pH conditions. Nanocontainers A and C, loaded with corrosion inhibitor, were dispersed in solutions with different pH values (pH 3, 7, 11, and 3.5 wt% NaCl solution and 1.87 mmol / L Al(NO3)3). The pH values of solutions 3, 7, and 11 were obtained by adjusting the pH by adding hydrochloric acid or sodium hydroxide to water. The concentration of the nanocontainers in the solution was 1 g / L. Inductively coupled plasma mass spectrometry (ICP-MS) was used to detect the inorganic corrosion inhibitor Ce. 3+ The concentration change over dispersion time was used to characterize the stimulus-response release performance of the nanocontainers. The mixed solution was continuously stirred until equilibrium was reached. Then, at a specific time, 6 mL of solution was taken out, and the unreleased corrosion inhibitor in the nanocontainers was filtered out using a syringe equipped with a microfilter. The Ce content in the extract was determined by ICP-MS. 3+ The concentration of Ce@mSiO2 was determined after 1400 min because the mesopores on the unmodified mSiO2 were through pores. 3+ The concentration is the maximum loading capacity, and calculations are based on this. Figure 4 Release efficiency under other conditions. Experimental results are as follows: Figure 4 As shown in the figure, the nanocontainer A (Ce@) prepared in Example 1 can be seen from the figure. f -mSiO2) under acidic and neutral conditions Ce 3+ The release amount is extremely small, and Ce is released under alkaline conditions. 3+The extremely high release rate indicates that the nano-container A prepared in this invention can only release under alkaline conditions, achieving controlled release of the corrosion inhibitor. The Ce@mSiO2 prepared in Comparative Example 5 can release large amounts under acidic conditions, as well as under neutral and alkaline conditions, lacking the controlled release effect. Therefore, it is suitable for the self-healing / corrosion early warning dual-functional coating of this invention based on the environmental response release of corrosion-causing and anode micro-regions. Furthermore, because Ce... 3+ Easy to react with OH - A reaction occurs to form a precipitate, therefore for Ce@ f -mSiO2 nanomaterials, when Ce@ f -mSiO2 breaks down at pH=11, leading to rapid release. Due to the precipitation reaction, Ce in the solution remains high in the later stages of the release curve. 3+ The ion concentration decreased significantly, therefore the detected release amount decreased.
[0037] Comparative Example 6 To prepare a 0.05 M NaCl solution, take three 50 μL portions of the NaCl solution. Add 4 mM 8-hydroxyquinoline-5-sulfonic acid to one portion to form solution a; add 4 mM cerium nitrate to another portion to form solution b; and add 1 mM 8-hydroxyquinoline-5-sulfonic acid and 3 mM cerium nitrate to the third portion to form solution c. Figure 5 The figures show the optical morphology of solutions a, b, and c after being placed on 2024 aluminum alloy for 24 hours (10 ℃, 85% relative humidity). In the figures, a, b, and c represent solutions a, b, and c, respectively. It can be seen that the corrosion inhibition effect of single cerium ions is better than that of single 8-HQS, while the corrosion inhibition effect of the compounded corrosion inhibitor is significantly better than that of the single inhibitor, indicating the enhanced synergistic corrosion inhibition effect of the compounded Ce(NO3)3 and 8-HQS.
[0038] In summary, the coating prepared in this embodiment uses functionalized mesoporous silica ( f -mSiO2) and zeolite imidazole framework compound (ZIF-8) were used as corrosion-responsive nanocontainers for corrosion anodizing / corrosion galvanizing, respectively loading corrosion inhibitors and fluorescent agents. Utilizing... fThe different charge states of 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane on the surface of -mSiO2 under different pH conditions enable the opening and closing of "nanogates," thereby overcoming the uncontrollable release of corrosion inhibitors under concentration gradients. This allows for the stimulation-responsive release of inorganic corrosion inhibitors in the cathodic region, where they precipitate and form a film, isolating the corrosive medium from the metal substrate and achieving long-term self-healing protection. Simultaneously, the acid and high-valence metal ion structure of ZIF-8 triggers the controlled release of fluorescent agents in the anodic region. The fluorescent agents interact with the metal surface, causing changes in the fluorescence signal and providing corrosion early warning. 8-HQS also has a corrosion-inhibiting effect. The coating of this invention exhibits excellent long-term protection and corrosion early warning sensitivity under the combined action of corrosion inhibitors, fluorescent agents, and anode-cathode responsive nanocontainers. It solves the problems of insufficient long-term protection, poor corrosion early warning, and insufficient sensitivity of traditional waterborne epoxy resin protective coatings, and is suitable for long-term protection and corrosion early warning of aluminum, iron, and other metal or alloy surfaces in harsh environments.
[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.
Claims
1. A dual-functional coating for self-healing and corrosion early warning based on environmental response release in corrosive anodic and micro-regions, characterized in that, The coating contains a nanocontainer A that responds to the corrosion cathodic microarea with a loaded corrosion inhibitor A and a nanocontainer B that responds to the corrosion anodic microarea with a loaded corrosion inhibitor B or a fluorescent agent. The method for preparing the nanocontainer A is as follows: S1. Dissolve hexadecyltrimethylammonium bromide in water to adjust the pH of the solution to 11.5~12.5, heat to 70~90℃ and keep at a constant temperature for 20~80 min, then add tetraethyl orthosilicate dropwise and stir vigorously for 1~3 h, cool and centrifuge, and further wash to obtain mSiO2 nanomaterials. S2. Disperse mSiO2 nanomaterials in anhydrous ethanol, then add 3-[2-(2-aminoethylamine)ethylamine]propyltrimethoxysilane to form a mixed solution. Heat the mixed solution to 100-120℃ and reflux for 5-7 h. Finally, centrifuge and wash to obtain... f -mSiO2 nanomaterials; S3, will f -mSiO2 nanomaterials were dispersed in an aqueous or ethanol solution containing corrosion inhibitor A. The suspension was placed under vacuum for more than 2 hours, followed by centrifugation to obtain the corrosion inhibitor-loaded material. f -mSiO2 nanocomposite material, i.e., nanocontainer A; The corrosion inhibitor A is an inorganic corrosion inhibitor, and the corrosion inhibitor B is an organic corrosion inhibitor.
2. The self-healing / corrosion early warning dual-function coating based on the environmental response release of corrosion anodic and corrosive micro-regions as described in claim 1, characterized in that, The coating is prepared as follows: Nanocontainers A and B are added to deionized water, followed by epoxy resin and curing agent. The mixture is stirred at high speed to obtain a composite epoxy resin coating. After being applied to a metal substrate and cured, a coating with dual functions of self-healing and corrosion warning is obtained.
3. The self-healing / corrosion early warning dual-function coating based on the environmental response release of corrosion anodic and corrosive micro-regions as described in claim 2, characterized in that, The mass ratio of nanocontainer A to nanocontainer B in the coating is 1:1 to 4:1, and the total mass of the two nanocontainers is 0.3 to 1.0 wt.% of the epoxy resin added.
4. The self-healing / corrosion early warning dual-function coating based on the environmental response release of corrosion anodic and corrosive micro-regions as described in claim 2, characterized in that, The method for preparing the nanocontainer B is as follows: 2-Methylimidazole and a fluorescent agent were added to methanol to form solution A; zinc nitrate hexahydrate was added to another portion of methanol to form solution B; solution B was slowly added to solution A, and the reaction was stirred at room temperature for 20-24 hours. The product collected by centrifugation was the nanocontainer B.
5. The self-healing / corrosion early warning dual-function coating based on the environmental response release of corrosion anodic and corrosive micro-regions as described in claim 4, characterized in that, The fluorescent agent is selected from any one of 8-hydroxyquinoline, 8-hydroxyquinoline-5-sulfonic acid, rhodamine B and its derivative FD1.
6. The self-healing / corrosion early warning dual-function coating based on the environmental response release of corrosion anodic and corrosive micro-regions as described in claim 1, characterized in that, In step S1, the concentration of hexadecyltrimethylammonium bromide in the reaction solution is 1.5~2.5 mg / mL, and the concentration of tetraethyl orthosilicate is 0.02~0.06 mol / L.
7. The self-healing / corrosion early warning dual-function coating based on the environmental response release of corrosion anodic and corrosive micro-regions as described in claim 6, characterized in that, In step S1, the product obtained by centrifugation is dispersed in a hydrochloric acid / ethanol mixed solution, stirred, and then centrifuged to achieve the purpose of cleaning.
8. The self-healing / corrosion early warning dual-function coating based on the environmental response release of corrosion anodic and corrosive micro-regions as described in claim 7, characterized in that, In step S2, the concentration of 3-[2-(2-aminoethylamine)ethylamine]propyltrimethoxysilane in the mixed solution is 0.40~1 mol / L.
9. The self-healing / corrosion early warning dual-function coating based on the environmental response release of corrosion anodic and corrosive micro-regions as described in claim 8, characterized in that, The corrosion inhibitor A is an inorganic salt containing cerium ions.