A super corrosion-resistant film solution and its application

Abstract

This invention relates to the field of copper metal surface protection and green corrosion prevention technology, and in particular to a super-corrosion-resistant film solution and its application. The raw materials of this super-corrosion-resistant film solution include citral, n-dodecyl mercaptan, and anhydrous ethanol; the concentration of citral in the super-corrosion-resistant film solution is 0.01-0.05M, and the concentration of n-dodecyl mercaptan is 0.01-0.05M. This invention employs a synergistic crosslinking system of citral and n-dodecyl mercaptan to construct a dense and stable corrosion-resistant composite film layer on the copper surface, which can significantly improve the corrosion resistance of copper substrates in natural seawater environments. The method of this 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, conforming to the current development trend of green manufacturing.

Description

Technical Field

[0001] This invention relates to the field of copper metal surface protection and green corrosion prevention technology, and in particular to a super corrosion-resistant film liquid and its application. Background Technology

[0002] Copper is widely used in marine engineering, precision metal processing of building and shipbuilding materials, and heat exchange equipment due to its excellent electrical and thermal conductivity, corrosion resistance, and cost advantages. However, the complex and variable marine environment, including high salinity, high humidity, and biofouling, makes copper susceptible to oxidation and corrosion from corrosive substances such as oxygen and chloride ions in seawater. This not only affects the stability of its performance but also limits its long-term service life, seriously threatening its safety in marine equipment and seawater heat exchange systems. To improve the corrosion resistance of copper, 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 generally have large thicknesses and significantly affect thermal and electrical conductivity, making them unsuitable for applications with stringent requirements for thermal and electrical conductivity. Electroplating precious metals or alloy layers is costly and involves complex processes with strict requirements on the substrate and equipment. Furthermore, commercially available corrosion inhibitors are prone to degradation and inactivation in marine environments, and some chemicals pose environmental pollution risks.

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

[0004] Based on the above, this invention provides a super-corrosion-resistant film solution and its application in preparing a super-corrosion-resistant film layer on the surface of a copper substrate. The preparation process of the super-corrosion-resistant film layer on the copper substrate surface of this invention is completed at room temperature using anhydrous ethanol and seawater as solvents, eliminating the need for strong acids, strong oxidants, or toxic and harmful solvents, and significantly improving the corrosion resistance of the copper substrate.

[0005] To achieve the above objectives, the present invention provides the following solution:

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

[0007] The concentration of citral in the ultra-corrosion resistant film 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 the application of the above-mentioned ultra-corrosion resistant film liquid in the preparation of an ultra-corrosion resistant film layer on the surface of a copper substrate.

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

[0010] The surface of a copper substrate is pre-crosslinked by immersing it in the aforementioned ultra-corrosion resistant film solution. Then, the pre-crosslinked copper substrate surface is immersed in a mixture of ultra-corrosion resistant film solution and seawater for crosslinking, thereby achieving the preparation of an ultra-corrosion resistant film layer on the surface of the copper substrate.

[0011] The fourth technical solution of the present invention is a method for improving the electrochemical impedance value of a copper substrate. The method described above is used to prepare an ultra-corrosion resistant film layer on the surface of the copper substrate to improve the electrochemical impedance value of the copper substrate.

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

[0013] This invention employs a synergistic crosslinking system of citral and n-dodecyl mercaptan to construct a dense and stable corrosion-resistant composite film on the copper surface. This significantly improves the corrosion resistance of the copper substrate in natural seawater environments and maintains the integrity of the corrosion-resistant film over a long period. Furthermore, this invention exhibits Ca... 2+ Mg 2+ Under the influence of ions, synergistic assembly and cross-linking reactions can be achieved on the copper surface without the introduction of traditional chemical cross-linking agents, thus ensuring the operability and feasibility of the ultra-corrosion resistant film preparation process.

[0014] The method of this 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. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 The results are electrochemical test results for the copper substrate with a super corrosion-resistant film on its surface, as shown in Example 1.

[0017] Figure 2 The image shows the microstructure of the ultra-corrosion resistant film prepared in Example 1.

[0018] Figure 3 The results are electrochemical tests conducted on the copper substrate with a highly corrosion-resistant film on its surface in Example 1 after immersion in seawater for 60 days.

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

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

[0021] Figure 6 This is a SEM image of the corrosion-resistant film on a copper substrate with a super-strong corrosion-resistant film layer on its surface after immersion corrosion for 14 days, as shown in Example 3.

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

[0023] Figure 8 The results are electrochemical test results for the copper substrate with a corrosion-resistant film on its surface in Comparative Example 2. Detailed Implementation

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of 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 terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0026] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0027] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

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

[0029] Unless otherwise specified, "room temperature" in this invention refers to 20-30°C.

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

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

[0032] If the concentration of citral in the super corrosion resistant film solution is too low, a dense composite film (super corrosion resistant film layer) cannot be prepared. 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 copper substrate surface shows a trend of first increasing and then decreasing. Therefore, the preferred concentration of citral in this invention is 0.01-0.05M.

[0033] If the concentration of dodecyl mercaptan in the preparation solution of the super corrosion resistant film is too low, the dense composite film cannot be prepared. When the concentration of 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 dodecyl mercaptan to 0.01-0.05M.

[0034] In a preferred embodiment of the present invention, the molar ratio of citral to n-dodecyl mercaptan is 1:4 to 4:1; a further preferred molar ratio is 1:2 to 2:1; and an even more 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, it will affect the density of the corrosion-resistant film and lead to changes in corrosion resistance. Therefore, the preferred molar ratio of the present invention is within the range of the above parameters.

[0036] A second aspect of the present invention provides the application of the above-mentioned ultra-corrosion resistant film liquid in the preparation of an ultra-corrosion resistant film layer on a copper substrate surface.

[0037] A third aspect of this invention provides a method for preparing an ultra-corrosion-resistant film layer on a copper substrate surface, comprising the following steps;

[0038] The surface of a copper substrate is pre-crosslinked by immersing it in the aforementioned ultra-corrosion resistant film solution. Then, the pre-crosslinked copper substrate surface is immersed in a mixture of ultra-corrosion resistant film solution and seawater for crosslinking, thereby achieving the preparation of an ultra-corrosion resistant film layer on the surface of the copper substrate.

[0039] Before immersing the copper substrate surface in an ultra-corrosion-resistant film solution for pre-crosslinking, the process also includes a rust removal and polishing step on 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 crosslinking temperature is room temperature and the crosslinking 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. If the pre-crosslinking or crosslinking time is too long, it will affect the density of the corrosion-resistant film and lead to a deterioration in 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 ultra-corrosion-resistant film-forming liquid to seawater in the mixture is (1-5):30. Natural seawater is replaced with a solution containing Ca... 2+ Mg 2+ Salt solutions with similar ion concentrations have the same effect and can facilitate cross-linking.

[0044] The fourth aspect of the present invention provides a method for improving the electrochemical impedance value of a copper substrate, wherein an ultra-corrosion resistant film layer is prepared on the surface of the copper substrate using the above-described preparation method, thereby improving the electrochemical impedance value of the copper substrate.

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

[0046] The purity of n-dodecyl mercaptan used in the embodiments of this 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 ≥97%.

[0048] The copper substrate used in this embodiment of the invention, after surface rust removal and polishing, has an electrochemical impedance value of 1.1 × 10⁻⁶. 4 Ω / cm 2 .

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

[0050] EIS and potentiodynamic polarization curves were performed using an electrochemical workstation (CHI660E, Shanghai Chenhua Instrument Co., Ltd.). Electrochemical measurements 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 using a sinusoidal signal amplitude of 10 mV, with the frequency range set to 10... -2 ~10 5 Hz.

[0051] The technical solutions provided by the present invention will be 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: Thoroughly mix citral, n-dodecyl mercaptan and anhydrous ethanol to obtain a super corrosion-resistant film solution; wherein, the concentration of citral in the super corrosion-resistant film solution is 0.05M and the concentration of n-dodecyl mercaptan in the super corrosion-resistant film solution is 0.05M.

[0054] Step 2: After removing rust and polishing the surface of the copper substrate, immerse the polished copper substrate surface in the above-mentioned super corrosion resistant film solution for 24 hours to allow the polished copper substrate surface to undergo pre-crosslinking with the super corrosion resistant film solution (at this time, the temperature of the super corrosion resistant film solution is room temperature).

[0055] 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 on the copper substrate surface was successfully prepared.

[0056] Electrochemical tests were performed on the copper substrate with a highly corrosion-resistant film on its surface in this embodiment, and the results are as follows: Figure 1 As shown. By Figure 1 It can be seen that its electrochemical impedance value is 3.5 × 10⁻⁶. 7 Ω / cm 2 The microstructure of the ultra-corrosion-resistant film on the surface of the copper substrate is as follows: Figure 2 As shown, by Figure 2 It can be seen that a corrosion-resistant film has been successfully prepared on the surface of the copper substrate, exhibiting a relatively dense nanoscale structure. Electrochemical tests were then conducted on the copper substrate with the ultra-corrosion-resistant film after immersion in natural seawater for 60 days. The results are as follows... Figure 3 ,Depend on Figure 3 It can be seen that after immersion and corrosion in natural seawater for 60 days, its electrochemical impedance modulus is 1.9 × 10⁻⁶. 7 Ω / cm 2This indicates that the ultra-corrosion resistant film prepared in Example 1 can significantly improve the corrosion resistance of copper substrates in natural seawater environments and can maintain the integrity of the corrosion resistant film 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 film solution is 0.01M and the concentration of n-dodecyl mercaptan is 0.04M; the other steps and parameters are the same as in Example 1.

[0059] Electrochemical tests were performed on the copper substrate with a highly corrosion-resistant film on its surface in this embodiment, and the results are as follows: Figure 4 As shown. By Figure 4 It can be seen that its electrochemical impedance value is 1.8 × 10⁻⁶. 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 film solution is 0.03M and the concentration of n-dodecyl mercaptan is 0.03M; the other steps and parameters are the same as in Example 1.

[0062] Electrochemical tests were performed on the copper substrate with a highly corrosion-resistant film on its surface in this embodiment, and the results are as follows: Figure 5 As shown. By Figure 5 It can be seen that the electrochemical impedance value is 2.0 × 10⁻⁶. 7 Ω / cm 2 .

[0063] Figure 6 This is a SEM image of the corrosion-resistant film on a copper substrate with a highly corrosion-resistant film layer on its surface, obtained in Example 3 after immersion corrosion for 14 days. Figure 6 It can be seen that after being immersed in natural seawater for 14 days, the ultra-corrosion resistant film still maintains a uniform and dense nanoscale 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 film solution in step 1; the other steps and parameters are the same as in Example 1.

[0066] The same electrochemical tests as in Example 1 were performed, and the results are as follows: Figure 7 As shown, the corrosion-resistant film containing only n-dodecyl mercaptan has a much lower impedance value than that of Example 1, with an impedance value of only 1.6 × 10⁻⁶. 5 Ω / cm 2 .

[0067] Comparative Example 2

[0068] The only difference from Example 1 is that the addition of dodecanethiol is omitted when preparing the super corrosion-resistant film solution in step 1; the other steps and parameters are the same as in Example 1.

[0069] The same electrochemical tests as in Example 1 were performed, and the results are as follows: Figure 8 As shown, the corrosion-resistant film prepared with only citral has an impedance value of only 2.4 × 10⁻⁶. 3 Ω / cm 2 It has almost no sustained-release properties.

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

Claims

1. A method for preparing a super corrosion-resistant film layer on the surface of a copper substrate, characterized in that, Includes the following steps: The surface of a copper substrate is pre-crosslinked by immersing it in an ultra-corrosion-resistant film solution, and then the pre-crosslinked copper substrate surface is immersed in a mixture of ultra-corrosion-resistant film solution and seawater for crosslinking, thereby achieving the preparation of an ultra-corrosion-resistant film layer on the surface of the copper substrate. The raw materials for the ultra-corrosion resistant film solution include citral, n-dodecyl mercaptan, and anhydrous ethanol. The concentration of citral in the super corrosion-resistant film solution is 0.01-0.05 M, and the concentration of n-dodecyl mercaptan is 0.01-0.05 M. The molar ratio of citral to n-dodecyl mercaptan is 1:4 to 4:

1.

2. The method for preparing a super corrosion-resistant film on a copper substrate surface according to claim 1, characterized in that, The pre-crosslinking temperature is room temperature, and the pre-crosslinking time is 12-24 h.

3. The method for preparing a super corrosion-resistant film on a copper substrate surface according to claim 1, characterized in that, The cross-linking temperature is room temperature, and the cross-linking time is 3-28 hours.

4. The method for preparing a super corrosion-resistant film on a copper substrate surface according to claim 1, characterized in that, The volume ratio of the ultra-corrosion resistant film liquid to seawater in the mixture is (1-5):

30.

5. A method for improving the electrochemical impedance value of a copper substrate, characterized in that, A super corrosion-resistant film layer is prepared on the surface of a copper substrate using the preparation method described in any one of claims 1-4, so as to improve the electrochemical impedance value of the copper substrate.

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