Super-strong corrosion-resistant film liquid and application thereof

Abstract

The invention relates to the technical field of copper metal surface protection and green corrosion prevention, in particular to super-strong corrosion-resistant film liquid and application thereof. The super-strong corrosion-resistant membrane liquid is prepared from the following raw materials: citral, n-dodecanethiol and absolute ethyl alcohol; the concentration of citral in the ultra-strong corrosion-resistant membrane liquid is 0.01 to 0.05 M, and the concentration of n-dodecanethiol in the ultra-strong corrosion-resistant membrane liquid is 0.01 to 0.05 M. According to the method, a citral and n-dodecanethiol synergistic crosslinking system is adopted, a compact and stable corrosion-resistant composite film layer is constructed on the copper surface, the corrosion resistance of a copper base material in a natural seawater environment can be remarkably improved, the method is easy and convenient to operate, a reaction system does not need to use strong acid, a strong oxidizing agent or a toxic solvent, the whole process is mild and environmentally friendly, and the method is suitable for industrial production. And the development trend of current green manufacturing is met.

Description

Technical Field

[0001] The invention relates to the technical field of copper metal surface protection and green anti-corrosion, in particular to a super corrosion-resistant membrane liquid and application thereof. Background Art

[0002] Copper is widely used in marine engineering, precision metal processing for construction and shipbuilding materials, and heat exchange equipment due to its excellent electrical and thermal conductivity, corrosion resistance, and cost-effectiveness. However, the complex and variable marine environment, characterized by high salinity, high humidity, and biofouling, makes copper susceptible to corrosive substances such as oxygen and chloride ions in seawater, leading to oxidation and corrosion. This not only affects its performance stability but also limits its long-term service life, seriously threatening its safe use in marine equipment and seawater heat exchange systems. To improve copper's corrosion resistance, various protective methods have been developed, such as organic coatings, electroplated metal layers, and corrosion inhibitor treatments. While organic coatings (such as epoxy and polyurethane) can effectively isolate corrosive media, they are generally thick and significantly affect thermal and electrical conductivity, making them unsuitable for applications requiring stringent thermal and electrical conductivity. Electroplating precious metal or alloy layers, on the other hand, is costly, complex, and requires strict substrate and equipment requirements. Furthermore, commercially available corrosion inhibitors are prone to degradation and ineffectiveness in marine environments, and some chemicals pose an environmental pollution risk.

[0003] Therefore, how to construct a green, dense and stable new copper surface protective film layer has become the current technical bottleneck. The preparation of long-lasting corrosion-resistant film is of great significance to significantly improve the corrosion resistance, oxidation resistance and processing adaptability of the copper surface. Summary of the Invention

[0004] Based on the above, the present invention provides a super-corrosion-resistant film solution and its use in preparing a super-corrosion-resistant film layer on a copper substrate surface. The super-corrosion-resistant film layer on a copper substrate surface is prepared at room temperature using anhydrous ethanol and seawater as solvents, eliminating the need for strong acids, strong oxidants, or toxic or hazardous solvents. This significantly improves the corrosion resistance of the copper substrate.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention is a super corrosion-resistant membrane liquid, the raw materials of which include citral, n-dodecyl mercaptan and anhydrous ethanol;

[0007] The concentration of citral in the super corrosion-resistant membrane solution is 0.01-0.05M, and the concentration of n-dodecyl mercaptan is 0.01-0.05M.

[0008] The second technical solution of the present invention is an application of the above-mentioned super corrosion-resistant film liquid in the preparation of a super corrosion-resistant film layer on the surface of a copper substrate.

[0009] A third technical solution of the present invention is a method for preparing a super corrosion-resistant film layer on the surface of a copper substrate, comprising the following steps:

[0010] The surface of the copper substrate is immersed in the above-mentioned super corrosion resistant film liquid for pre-crosslinking, and then the pre-crosslinked copper substrate surface is immersed in a mixture of the super corrosion resistant film liquid and seawater for crosslinking to achieve the preparation of the super corrosion resistant film layer on the surface of the copper substrate.

[0011] A fourth technical solution of the present invention is a method for improving the electrochemical impedance value of a copper substrate, which utilizes the above-mentioned preparation method to prepare a super corrosion-resistant film layer on the surface of the copper substrate to achieve the improvement of the electrochemical impedance value of the copper substrate.

[0012] The present invention discloses the following technical effects:

[0013] The present invention adopts citral and n-dodecyl mercaptan synergistic crosslinking system to achieve the construction of dense and stable corrosion-resistant composite film on the copper surface, which can significantly improve the corrosion resistance of the copper substrate in the natural seawater environment and maintain the integrity of the corrosion-resistant film for a long time. 2+ Mg 2+ Under the action of ions, coordinated assembly and cross-linking reactions can be achieved on the copper surface without introducing traditional chemical cross-linking agents, thus ensuring the operability and feasibility of the preparation process of super corrosion-resistant films.

[0014] The method of the present invention is simple to operate, and the reaction system does not require the use of strong acids, strong oxidants or toxic solvents. The overall process is mild and environmentally friendly, which is in line with the current development trend of green manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 These are the electrochemical test results of the copper substrate with a super corrosion-resistant film layer on its surface in Example 1.

[0017] Figure 2 This is a microscopic morphology of the ultra-corrosion-resistant film layer prepared in Example 1.

[0018] Figure 3 These are the electrochemical test results of the copper substrate with the super corrosion-resistant film layer on its surface in Example 1 after being immersed in seawater for 60 days.

[0019] Figure 4 Electrochemical test results of the copper substrate with a super corrosion-resistant film layer on its surface in Example 2.

[0020] Figure 5 These are the electrochemical test results of the copper substrate with a super corrosion-resistant film layer on its surface in Example 3.

[0021] Figure 6 This is an SEM image of the resistant film of the copper substrate having a super corrosion-resistant film layer on its surface in Example 3 after being immersed in corrosion for 14 days.

[0022] Figure 7 These are the electrochemical test results of the copper substrate with a corrosion-resistant film layer on its surface in Comparative Example 1.

[0023] Figure 8 These are the electrochemical test results of the copper substrate with a corrosion-resistant film layer on its surface in Comparative Example 2. DETAILED DESCRIPTION

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0026] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0027] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0028] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0029] The "room temperature" mentioned in the present invention, unless otherwise specified, refers to 20-30°C.

[0030] The first aspect of the present invention provides a super corrosion-resistant membrane solution, the raw materials of which include citral, n-dodecyl mercaptan and anhydrous ethanol;

[0031] The concentration of citral in the super corrosion-resistant membrane solution is 0.01-0.05M, and the concentration of n-dodecyl mercaptan is 0.01-0.05M.

[0032] The concentration of citral in the super corrosion-resistant film liquid is too low to achieve the preparation of a dense composite film (super corrosion-resistant film layer). When the concentration of citral is greater than or equal to 0.01M, the impedance value of the super corrosion-resistant film layer prepared on the surface of the copper substrate shows a trend of first increasing and then decreasing. Therefore, the present invention preferably limits the concentration of citral to 0.01-0.05M.

[0033] The concentration of n-dodecyl mercaptan in the super corrosion-resistant film preparation liquid is too low to achieve the preparation of a dense composite film. When the concentration of n-dodecyl mercaptan is greater than or equal to 0.01M, the impedance value of the super corrosion-resistant film layer prepared on the surface of the copper substrate shows a trend of first increasing and then decreasing. Therefore, the present invention limits the concentration of n-dodecyl mercaptan to 0.01-0.05M.

[0034] In a preferred embodiment of the present invention, the molar ratio of the citral to the n-dodecyl mercaptan is 1:4 to 4:1; a further preferred molar ratio is 1:2 to 2:1; and a further preferred molar ratio is 1:1 to 2:1.

[0035] If the molar ratio of citral to n-dodecyl mercaptan is too large or too small, the density of the corrosion-resistant film will be affected, resulting in a change in corrosion resistance. Therefore, the present invention preferably limits the molar ratio to the above parameter range.

[0036] A second aspect of the present invention provides a use of the above-mentioned super corrosion-resistant film liquid in preparing a super corrosion-resistant film layer on the surface of a copper substrate.

[0037] A third aspect of the present invention provides a method for preparing a super corrosion-resistant film layer on the surface of a copper substrate, comprising the following steps:

[0038] The surface of the copper substrate is immersed in the above-mentioned super corrosion resistant film liquid for pre-crosslinking, and then the pre-crosslinked copper substrate surface is immersed in a mixture of the super corrosion resistant film liquid and seawater for crosslinking to achieve the preparation of the super corrosion resistant film layer on the surface of the copper substrate.

[0039] Before the copper substrate surface is immersed in the super corrosion-resistant film liquid for pre-crosslinking, the process also includes the step of removing rust and polishing the copper substrate surface.

[0040] In a preferred embodiment of the present invention, the pre-crosslinking temperature is room temperature, and the pre-crosslinking time is 12-24 hours.

[0041] In a preferred embodiment of the present invention, the cross-linking temperature is room temperature, and the cross-linking time is 3-28 hours; more preferably 8-16 hours; and even more preferably 11-13 hours.

[0042] If the pre-crosslinking or crosslinking time is too short, it will affect the pre-crosslinking or crosslinking effect. When the pre-crosslinking or crosslinking time is too long, it will affect the density of the corrosion-resistant film, resulting in poor corrosion resistance. Therefore, the present invention preferably limits the pre-crosslinking and crosslinking time to the above parameter range.

[0043] In a preferred embodiment of the present invention, the volume ratio of the super corrosion resistant membrane liquid to seawater in the mixed solution is (1-5):30. The natural seawater is replaced by a mixture containing Ca 2+ Mg 2+ Salt solutions with similar ion concentrations have the same effect and can achieve smooth cross-linking.

[0044] A fourth aspect of the present invention provides a method for improving the electrochemical impedance value of a copper substrate, wherein the above-mentioned preparation method is used to prepare a super corrosion-resistant film layer on the surface of the copper substrate to achieve the improvement of the electrochemical impedance value of the copper substrate.

[0045] Unless otherwise specified, the technical solutions described in the present invention are all conventional solutions in the field, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0046] The purity of n-dodecyl mercaptan used in the embodiments of the present invention is ≥98%.

[0047] The citral used in the embodiments of the present invention is a mixture of cis- and trans-isomers of 3,7-dimethyl-2,6-octadienal, with a purity of ≥97%.

[0048] The electrochemical impedance value of the copper substrate used in the embodiment of the present invention after surface rust removal and polishing is 1.1×10 4 Ω / cm 2 .

[0049] The testing method involved in the present invention is as follows:

[0050] Electrochemical workstation (CHI660E, Shanghai Chenhua Instrument Co., Ltd.) was used for EIS and potentiodynamic polarization curve tests. Electrochemical tests were conducted in a three-electrode system, with Ag / AgCl (3.0 M KCl) as the reference electrode and a graphite sheet as the counter electrode. After the open circuit potential (OCP) stabilized, EIS was scanned with a sinusoidal signal amplitude of 10 mV and a frequency range of 10 -2 ~10 5 Hz.

[0051] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0052] Example 1

[0053] Step 1: Fully mix citral, n-dodecyl mercaptan and anhydrous ethanol to obtain a super corrosion resistant membrane liquid; wherein the concentration of citral in the super corrosion resistant membrane liquid is 0.05M, and the concentration of n-dodecyl mercaptan in the super corrosion resistant membrane liquid is 0.05M.

[0054] Step 2: After the copper substrate surface is rust-removed and polished, the polished copper substrate surface is immersed in the above-mentioned super corrosion-resistant film liquid for 24 hours to pre-crosslink the polished copper substrate surface with the super corrosion-resistant film liquid (the temperature of the super corrosion-resistant film liquid is room temperature at this time).

[0055] In step 3, the pre-crosslinked copper substrate and the ultra-corrosion-resistant film solution were added to natural seawater for crosslinking for 12 hours. The volume ratio of the ultra-corrosion-resistant film solution to natural seawater was 1:30. After crosslinking, the ultra-corrosion-resistant film layer was formed on the copper substrate surface.

[0056] The copper substrate with the super corrosion resistant film layer on the surface of this embodiment was subjected to electrochemical testing, and the results were as follows: Figure 1 As shown. Figure 1 It can be seen that its electrochemical impedance value is 3.5×10 7 Ω / cm 2 The microstructure of the super corrosion resistant film on the copper substrate surface is as follows: Figure 2 As shown by Figure 2 It can be seen that the corrosion-resistant film has been successfully prepared on the surface of the copper substrate and presents a relatively compact nano-scale structure. The copper substrate with the super corrosion-resistant film on the surface was immersed in natural seawater for 60 days and then electrochemically tested. The results are as follows Figure 3 ,Depend on Figure 3 It can be seen that after immersion in natural seawater for 60 days, the electrochemical impedance spectroscopy value is 1.9×10 7 Ω / cm 2, which indicates that the super corrosion-resistant film layer prepared in Example 1 can significantly improve the corrosion resistance of the copper substrate in the natural seawater environment and can maintain the integrity of the corrosion-resistant film layer for a long time.

[0057] Example 2

[0058] The only difference from Example 1 is that in step 1, the concentration of citral in the super corrosion-resistant membrane solution is 0.01M and the concentration of n-dodecyl mercaptan is 0.04M; the remaining steps and parameters are the same as those in Example 1.

[0059] The copper substrate with the super corrosion resistant film layer on the surface of this embodiment was subjected to electrochemical testing, and the results were as follows: Figure 4 As shown. Figure 4 It can be seen that its electrochemical impedance value is 1.8×10 7 Ω / cm 2 .

[0060] Example 3

[0061] The only difference from Example 1 is that in step 1, the concentration of citral in the super corrosion-resistant membrane solution is 0.03M and the concentration of n-dodecyl mercaptan is 0.03M; the remaining steps and parameters are the same as those in Example 1.

[0062] The copper substrate with the super corrosion resistant film layer on the surface of this embodiment was subjected to electrochemical testing, and the results were as follows: Figure 5 As shown. Figure 5 It can be seen that the electrochemical impedance value is 2.0×10 7 Ω / cm 2 .

[0063] Figure 6 This is the SEM image of the resistant film of the copper substrate with super corrosion resistant film layer in Example 3 after immersion corrosion for 14 days. Figure 6 It can be seen that after 14 days of immersion in natural seawater, the super corrosion-resistant film layer can still maintain a uniform and dense nano-scale structure, and no obvious corrosion products are observed.

[0064] Comparative Example 1

[0065] The only difference from Example 1 is that the addition of citral is omitted when preparing the super corrosion-resistant membrane solution in step 1; the remaining steps and parameters are the same as those in Example 1.

[0066] The same electrochemical test as in Example 1 was carried out, and the results were as follows Figure 7 As shown in the figure, the corrosion-resistant film with only n-dodecyl mercaptan has a much lower impedance than that of Example 1, which is only 1.6×10 5 Ω / cm 2 .

[0067] Comparative Example 2

[0068] The only difference from Example 1 is that the addition of n-dodecyl mercaptan is omitted when preparing the super corrosion-resistant membrane solution in step 1; the remaining steps and parameters are the same as those in Example 1.

[0069] The same electrochemical test as in Example 1 was carried out, and the results were as follows Figure 8 As shown in the figure, the corrosion-resistant film prepared when only citral exists has a resistance value of only 2.4×10 3 Ω / cm 2 , almost no sustained-release performance.

[0070] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A super corrosion-resistant membrane liquid, characterized in that: The raw materials include citral, n-dodecyl mercaptan and anhydrous ethanol; The concentration of citral in the super corrosion-resistant membrane solution is 0.01-0.05M, and the concentration of n-dodecyl mercaptan is 0.01-0.05M.

2. The super corrosion-resistant membrane solution according to claim 1, characterized in that: The molar ratio of the citral to the n-dodecyl mercaptan is 1:4 to 4:

1.

3. Use of the super corrosion-resistant film solution according to claim 1 or 2 in preparing a super corrosion-resistant film layer on the surface of a copper substrate.

4. A method for preparing a super corrosion-resistant film layer on a copper substrate surface, characterized in that: The following steps are involved: The surface of the copper substrate is immersed in the super corrosion resistant film liquid described in claim 1 or 2 for pre-crosslinking, and then the pre-crosslinked surface of the copper substrate is immersed in a mixture of the super corrosion resistant film liquid and seawater for crosslinking, thereby realizing the preparation of the super corrosion resistant film layer on the surface of the copper substrate.

5. The method for preparing a super corrosion-resistant film layer on a copper substrate according to claim 4, wherein: The pre-crosslinking temperature is room temperature, and the pre-crosslinking time is 12-24 hours.

6. The method for preparing a super corrosion-resistant film layer on a copper substrate according to claim 4, wherein: The cross-linking temperature is room temperature, and the cross-linking time is 3-28 hours.

7. The method for preparing a super corrosion-resistant film layer on a copper substrate according to claim 4, wherein: The volume ratio of the super corrosion-resistant membrane liquid to seawater in the mixed liquid is (1-5):

30.

8. A method for improving the electrochemical impedance value of a copper substrate, characterized in that: The preparation method according to any one of claims 4 to 7 is used to prepare a super corrosion-resistant film layer on the surface of a copper substrate, so as to improve the electrochemical impedance value of the copper substrate.

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