A compound for detecting the corrosion of iron-containing metals, its composition, an iron-containing metal coated component, and a detection method

Abstract

The present invention discloses a compound for detecting the corrosion of iron-containing metals, its composition, an iron-containing metal coated part, and a detection method. The composition for detecting the corrosion of iron-containing metals includes a compound, an epoxy resin, and a curing agent. By using the compound to detect the corrosion of iron-containing metals, the compound combines with Fe3+ to cause fluorescence quenching, having a "Turn-Off" fluorescence effect, thus having good fluorescence sensing performance, so that the corrosion points of iron-containing metals can be detected as early as possible, improving the detection limit and detection sensitivity.

Description

Technical Field

[0001] The present invention relates to the technical field of metal corrosion, and particularly to a compound for detecting the corrosion of iron-containing metals, its composition, iron-containing metal coated parts, and a detection method. Background Art

[0002] Due to their good electrical conductivity, thermal conductivity, corrosion resistance, and excellent mechanical properties, metals are widely used in light industry, building materials, aerospace, and other fields. However, metals are prone to pitting corrosion, which is extremely difficult to detect in the initial stage of corrosion. Once corrosion pits are formed, they will further penetrate, seriously threatening the use safety of equipment such as automobiles, ships, and even aircraft. Therefore, early corrosion monitoring before obvious visible corrosion occurs is of great significance for their service life and service safety.

[0003] Corrosion monitoring technology can mark the area where early corrosion occurs, helping to detect and carry out corresponding maintenance in a timely manner. Currently, the commonly used corrosion monitoring technology mainly monitors through the color change of indicators, including acid-base indicators and metal ion indicators. The operation of using colorimetric indicators is relatively easy, but problems such as a large color change range of the indicators and difficult color change discrimination will interfere with corrosion monitoring, resulting in low sensitivity and low detection limit in the detection of metal pitting corrosion. Summary of the Invention

[0004] The main object of the present invention is to propose a compound for detecting the corrosion of iron-containing metals, aiming to solve the problems of low sensitivity and low detection limit in the detection of metal pitting corrosion in the prior art.

[0005] To achieve the above object, the present invention proposes a compound for detecting the corrosion of iron-containing metals, and the structural formula of the compound is as follows:

[0006]

[0007] The present invention also proposes a composition for detecting the corrosion of iron-containing metals, including a compound, epoxy resin, and a curing agent, wherein the structural formula of the compound is as follows:

[0008]

[0009] Optionally, in the composition for detecting the corrosion of iron-containing metals, the mass percentage of the compound is (0.1 - 1)‰.

[0010] The present invention also proposes a preparation method of a composition for detecting the corrosion of iron-containing metals, including the following steps:

[0011] S10. Add the compound to tetrahydrofuran to obtain a compound solution;

[0012] S20. Mix the compound solution with epoxy resin, and obtain a mixture after evaporation and drying.

[0013] S30. Add a curing agent to the mixture to obtain a composition for detecting the corrosion of iron-containing metal.

[0014] Optionally, in step S10, 4 - 20 mg of the compound is added to each 1 mL of tetrahydrofuran.

[0015] Optionally, in step S20, 8 - 20 g of epoxy resin is added to each 1 mL of the compound solution.

[0016] Optionally, in step S20, the temperature of evaporation and drying is 60 - 70 °C; and / or

[0017] In step S20, the time of evaporation and drying is 1 - 3 h.

[0018] The present invention also provides an iron-containing metal coated part, including:

[0019] A metal substrate containing iron element; and

[0020] A composition coating for detecting the corrosion of iron-containing metal, provided on the upper side of the metal substrate, and the composition coating for detecting the corrosion of iron-containing metal includes the composition for detecting the corrosion of iron-containing metal.

[0021] Optionally, it further includes an anti-corrosion coating, wherein the anti-corrosion coating is provided on the side of the composition coating for detecting the corrosion of iron-containing metal away from the metal substrate; and / or

[0022] The thickness of the composition coating for detecting the corrosion of iron-containing metal is 100 - 300 μm.

[0023] The present invention also provides a method for detecting pitting corrosion of iron-containing metal, including the following steps:

[0024] Use the iron-containing metal coated part described above;

[0025] Perform fluorescence quenching detection on the iron-containing metal coated part under an ultraviolet lamp;

[0026] Judge whether pitting corrosion occurs on the metal according to the detection result.

[0027] The present invention provides a compound for detecting the corrosion of iron-containing metal. By using the compound for detecting the corrosion of iron-containing metal, the corrosion points of iron-containing metal can be detected as early as possible, improving the detection limit and detection sensitivity. Description of the Drawings

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0029] Figure 1 Structural schematic diagram of the iron-containing metal coating part of Embodiment VI of the present invention;

[0030] Figure 2 Fluorescence spectra of Embodiment VI of the present invention before and after soaking in a solution of 160 ppm Fe 3+ ;

[0031] Figure 3 Fluorescence quenching diagram under ultraviolet light of fluorescence pitting corrosion in the early stage of corrosion of Embodiment VI of the present invention.

[0032] Explanation of the reference numerals of the attached drawings in the embodiments provided by the present invention:

[0033] Label Name Label Name 100 Iron-containing metal coated part 2 Composition coating for detecting corrosion of iron-containing metal 1 Metal substrate 3 Anticorrosion coating

[0034] The realization of the object, functional features and advantages of the present invention will be further described in conjunction with the embodiments with reference to the drawings. Detailed implementation manners

[0035] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. For those conditions not specified in the embodiments, they shall be carried out according to the conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase. In addition, the meaning of "and / or" appearing throughout the text includes three parallel solutions. Taking "A and / or B" as an example, it includes Solution A, or Solution B, or the solution where A and B are satisfied simultaneously. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0036] Corrosion monitoring techniques can mark the areas where early corrosion occurs, helping to detect and perform corresponding maintenance in a timely manner. Currently, the commonly used corrosion monitoring techniques, in addition to monitoring through the color change of indicators, include acid-base indicators and metal ion indicators. In recent years, monitoring through fluorescent agents has also emerged, such as organic compounds like anthraquinones, azo compounds, and quinolines. Under general conditions, pitting corrosion of metals is an oxygen absorption corrosion process. Local anodes and local cathodes are formed at the corroded parts. The anodic reaction produces M + , making the concentration of M + increase; the cathodic reaction generates a large amount of OH - , resulting in an obvious change in the pH of the cathodic area. To monitor the corrosion status of carbon steel, fluorescent substances that respond to the change of Fe 2+ / Fe 3+ or pH need to be selected.

[0037] The applications of similar sensors have become increasingly popular. In the past decade, molecules with similar properties have been found to act as chemical sensors, biological probes, stimulus-responsive nanomaterials, and active layers in the construction of effective organic light-emitting diodes. However, many of these molecules have the problem of difficult synthesis. In addition, for fluorescence sensors to ensure sensitivity, strong fluorophores are required, with good photoluminescence properties and chemical stability. In addition, they need not interfere with the performance of the corrosion-resistant coating. In view of this, the present invention discloses a compound for detecting the corrosion of iron-containing metals, and the structural formula of the compound is as follows:

[0038]

[0039] The compound (AMP) is simple to synthesize, is a typical Schiff base, and has excellent fluorophores. It can self-assemble into a dimer structure after binding with metal cations, thus generating P–P* and A–A* excimer fluorescence, and thus has good fluorescence sensing performance and is not likely to react with the coating of metal parts, with good stability.

[0040] In the technical solution of the present invention, by using AMP to detect the corrosion of iron-containing metals, the fluorescence quenching is generated by the combination of AMP and Fe 3+ , having a "Turn-Off" fluorescence effect, and thus having good fluorescence sensing performance, so that the corrosion points of iron-containing metals can be detected as early as possible, improving the detection limit and detection sensitivity.

[0041] The present invention also proposes a composition for detecting the corrosion of iron-containing metals, including the compound (AMP), epoxy resin, and curing agent. Among them, the structural formula of the compound is as follows:

[0042]

[0043] In the technical solution of the present invention, by combining AMP with epoxy resin and a curing agent to form a composition, it is convenient to uniformly disperse AMP in the resin and fix it on the surface of the metal part to be tested, so that AMP is uniformly distributed, facilitating the detection of pitting corrosion of the entire workpiece.

[0044] Further, in the composition for detecting the corrosion of iron-containing metals, the mass percentage of AMP is (0.1 - 1)‰. By controlling the mass percentage of AMP in the composition, both the usage amount of AMP can be reduced and a better detection effect can be achieved. Among them, the mass percentage of AMP can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, and preferably 0.5%.

[0045] The present invention also provides a preparation method of a composition for detecting the corrosion of iron-containing metals, comprising the following steps:

[0046] S10. Add AMP into tetrahydrofuran to obtain a compound solution;

[0047] S20. Mix the compound solution with epoxy resin, and after evaporation and drying, obtain a mixture;

[0048] S30. Add a curing agent to the mixture to obtain a composition for detecting the corrosion of iron-containing metals.

[0049] In the technical solution of the present invention, by using the method of dissolving with a solvent and then evaporating, AMP is introduced into the composition. AMP is first dissolved in the tetrahydrofuran solution, then uniformly dispersed in the resin, and finally the tetrahydrofuran is evaporated and discharged, making AMP uniformly dispersed in the composition, facilitating subsequent use on the surface of the workpiece.

[0050] Further, in step S10, 4 - 20 mg of AMP is added to each 1 mL of tetrahydrofuran. This can make AMP fully dissolved in tetrahydrofuran.

[0051] Further, in step S20, 8 - 20 g of epoxy resin is added to each 1 mL of the compound solution. This can make the compound solution uniformly mixed in the epoxy resin.

[0052] Further, in step S20, the temperature for evaporation and drying is 60 - 70 °C. At this temperature, tetrahydrofuran can be fully evaporated, avoiding the residue of organic solvents. If the temperature is too high, the surface evaporates too fast and the internal organic solvents cannot be fully evaporated. If the temperature is too low, the evaporation efficiency is too low.

[0053] Further, in step S20, the time for evaporation and drying is 1 - 3 h. At this time, tetrahydrofuran can be fully evaporated, avoiding the residue of organic solvents.

[0054] It should be noted that the above evaporation drying temperature and evaporation drying time can be set separately or simultaneously. When set simultaneously, the evaporation efficiency of the organic solvent is better.

[0055] As Figure 1 shown, the present invention also provides an iron-containing metal coated part 100, comprising:

[0056] a metal matrix 1 containing iron element; and a composition coating 2 for detecting the corrosion of the iron-containing metal, provided on the upper side of the metal matrix 1, and the composition coating 2 for detecting the corrosion of the iron-containing metal includes the composition for detecting the corrosion of the iron-containing metal.

[0057] In the technical solution of the present invention, by coating the composition for detecting the corrosion of the iron-containing metal onto the metal matrix 1, a composition coating 2 for detecting the corrosion of the iron-containing metal is formed on the surface of the iron-containing metal part, so that Fe 3+ on the surface of the iron-containing metal part combines with AMP, thereby causing a fluorescence quenching effect of AMP, and different from the collective fluorescence quenching when the compound solution encounters Fe 3+ When using the coating, fluorescence quenching only occurs in the area where the concentration of Fe 3+ increases at the pitting corrosion site. According to the fluorescence quenching site, it can be judged whether pitting corrosion occurs and the location of pitting corrosion, improving the sensitivity of AMP detection.

[0058] Furthermore, the iron-containing metal coated part further includes an anti-corrosion coating 3. Wherein, the anti-corrosion coating 3 is provided on the side of the composition coating 2 for detecting the corrosion of the iron-containing metal away from the metal matrix 1. By providing the anti-corrosion coating 3 on the side of the composition coating 2 for detecting the corrosion of the iron-containing metal away from the metal matrix 1, on the one hand, it can prevent the iron-containing metal coated part 100 from corroding, and on the other hand, it can protect the composition coating 2 for detecting the corrosion of the iron-containing metal, avoiding the composition coating 2 for detecting the corrosion of the iron-containing metal from deteriorating in properties and becoming ineffective due to environmental factors or combining with Fe 3+ in the external environment, resulting in inaccurate test results.

[0059] Furthermore, the thickness of the composition coating 2 for detecting the corrosion of the iron-containing metal is 100 - 300 μm. Through the film thickness within this range, it can ensure that AMP can accurately detect the points where the concentration of Fe 3+ increases, while avoiding the influence of too thick film thickness on the detection accuracy and the problem of increased cost.

[0060] It should be noted that the thicknesses of the above anti-corrosion coating 3 and the composition coating 2 for detecting the corrosion of the iron-containing metal can be set separately or simultaneously. When set simultaneously, the detection sensitivity of the composition coating 2 for detecting the corrosion of the iron-containing metal is higher.

[0061] The present invention also provides a method for detecting pitting corrosion of iron-containing metals, comprising the following steps:

[0062] Using the iron-containing metal coating;

[0063] Performing fluorescence quenching detection on the iron-containing metal coating under an ultraviolet lamp;

[0064] Judging whether pitting corrosion occurs on the metal according to the detection result.

[0065] In the technical solution of the present invention, by detecting the fluorescence on the surface of the iron-containing metal coating under an ultraviolet lamp, and judging whether pitting corrosion occurs on the metal coating by whether fluorescence quenching occurs, it is convenient, fast, has a high degree of visualization, and is convenient for practical application.

[0066] The following further details the technical solution of the present invention with reference to specific embodiments and drawings. It should be understood that the following embodiments are only used to explain the present invention and are not used to limit the present invention.

[0067] Example 1

[0068] A preparation method of a composition for detecting the corrosion of iron-containing metals, comprising the following steps:

[0069] S10: Adding 4 mg of AMP to 1 mL of tetrahydrofuran to obtain a compound solution;

[0070] S20: Mixing 1 mL of the compound solution with 8 g of epoxy resin, and evaporating and drying at 60 °C for 3 h to obtain a mixture;

[0071] S30: Adding a curing agent to the mixture so that the mass percentage of AMP is 0.1‰ to obtain a composition for detecting the corrosion of iron-containing metals.

[0072] Example 2

[0073] A preparation method of a composition for detecting the corrosion of iron-containing metals, comprising the following steps:

[0074] S10: Adding 7 mg of AMP to 1 mL of tetrahydrofuran to obtain a compound solution;

[0075] S20: Mixing 1 mL of the compound solution with 10 g of epoxy resin, and evaporating and drying at 62 °C for 2.5 h to obtain a mixture;

[0076] S30: Adding a curing agent to the mixture so that the mass percentage of AMP is 0.3‰ to obtain a composition for detecting the corrosion of iron-containing metals.

[0077] Example 3

[0078] A method for preparing a composition for detecting the corrosion of iron-containing metals, comprising the following steps:

[0079] S10. Add 10 mg of AMP to 1 mL of tetrahydrofuran to obtain a compound solution;

[0080] S20. Mix 1 mL of the compound solution with 13 g of epoxy resin, and after evaporation and drying at 65 °C for 2 h, obtain a mixture;

[0081] S30. Add a curing agent to the mixture so that the mass percentage of AMP is 0.5‰ to obtain a composition for detecting the corrosion of iron-containing metals.

[0082] Example 4

[0083] A method for preparing a composition for detecting the corrosion of iron-containing metals, comprising the following steps:

[0084] S10. Add 20 mg of AMP to 1 mL of tetrahydrofuran to obtain a compound solution;

[0085] S20. Mix 1 mL of the compound solution with 20 g of epoxy resin, and after evaporation and drying at 70 °C for 1 h, obtain a mixture;

[0086] S30. Add a curing agent to the mixture so that the mass percentage of AMP is 1‰ to obtain a composition for detecting the corrosion of iron-containing metals.

[0087] Example 5

[0088] An iron-containing metal coated part, comprising:

[0089] A metal substrate containing iron elements;

[0090] A composition coating for detecting the corrosion of iron-containing metals, provided on the upper side of the metal substrate, and obtained by coating with the composition for detecting the corrosion of iron-containing metals prepared by the preparation method of the composition for detecting the corrosion of iron-containing metals in Example 1, with a thickness of 100 μm;

[0091] An anti-corrosion coating, provided on the side of the composition coating for detecting the corrosion of iron-containing metals facing away from the metal substrate.

[0092] Example 6

[0093] An iron-containing metal coated part, comprising:

[0094] A metal substrate containing iron elements;

[0095] A composition coating for detecting the corrosion of iron-containing metals, disposed on the upper side of the metal substrate, obtained by coating with the composition for detecting the corrosion of iron-containing metals prepared by the preparation method of the composition for detecting the corrosion of iron-containing metals in Example 2, with a thickness of 150 μm;

[0096] An anti-corrosion coating, disposed on the side of the composition coating for detecting the corrosion of iron-containing metals facing away from the metal substrate.

[0097] Example 7

[0098] An iron-containing metal coated part, comprising:

[0099] A metal substrate containing iron element;

[0100] A composition coating for detecting the corrosion of iron-containing metals, disposed on the upper side of the metal substrate, obtained by coating with the composition for detecting the corrosion of iron-containing metals prepared by the preparation method of the composition for detecting the corrosion of iron-containing metals in Example 3, with a thickness of 200 μm;

[0101] An anti-corrosion coating, disposed on the side of the composition coating for detecting the corrosion of iron-containing metals facing away from the metal substrate.

[0102] Example 8

[0103] An iron-containing metal coated part, comprising:

[0104] A metal substrate containing iron element;

[0105] A composition coating for detecting the corrosion of iron-containing metals, disposed on the upper side of the metal substrate, obtained by coating with the composition for detecting the corrosion of iron-containing metals prepared by the preparation method of the composition for detecting the corrosion of iron-containing metals in Example 4, with a thickness of 300 μm;

[0106] An anti-corrosion coating, disposed on the side of the composition coating for detecting the corrosion of iron-containing metals facing away from the metal substrate.

[0107] Comparative Example 1

[0108] A compound solution with a concentration of 0.5‰.

[0109] Performance test

[0110] In order to test the response ability of AMP to Fe 3+ ions in the composition coating for detecting the corrosion of iron-containing metals, the iron-containing metal coated part of Example 6 and the compound solution of Comparative Example 1 were taken and immersed in a solution of 160 ppm Fe 3+ The fluorescence spectra before and after immersion were detected. The compound solution in the comparative example was in contact with 160 ppm Fe 3+ in the liquid, resulting in collective fluorescence quenching. AsFigure 2 as shown, where a is the curve before immersion and b is the curve after immersion. The coating of Example 6 has a fluorescence intensity decrease after being placed in 160 ppm Fe 3+ for 96 h, but there is no complete fluorescence quenching phenomenon, indicating that the film has a certain response ability to Fe3+, and the detection limit of the film is higher than that of the AMP solution.

[0111] To study the corrosion detection effect of the coating, the iron-containing metal coated part of Example 6 was placed in 3.5% NaCl. After 15 days of immersion, no visible corrosion marks were found on the metal surface. When placed under an ultraviolet lamp, as Figure 3 shown, a visible fluorescence "Turn-Off" phenomenon was found as Figure 3 shown in d. Subsequently, the fluorescence of the coating immersed for different times was tested under a fluorescence microscope. There was blue fluorescence in the non-corroded area as Figure 3 shown in a, there was fluorescence quenching at the site of ultra-mild pitting corrosion as Figure 3 shown in b. When the visible "Turn-Off" phenomenon occurred under the ultraviolet lamp, it was as Figure 3 shown in c under the fluorescence microscope, and a fluorescence quenching phenomenon of several hundred micrometers occurred. At this time, no obvious corrosion products were generated on the metal, indicating that minor pitting corrosion was occurring. It shows that the coating can detect the early corrosion of the metal with the naked eye.

[0112] In summary, the present invention provides a compound for detecting the corrosion of iron-containing metals, a composition for detecting the corrosion of iron-containing metals, an iron-containing metal coated part, and a method for detecting pitting corrosion of iron-containing metals. The composition for detecting the corrosion of iron-containing metals includes a compound, an epoxy resin, and a curing agent. By using AMP to detect the corrosion of iron-containing metals, the combination of AMP and Fe 3+ results in fluorescence quenching, having a "Turn-Off" fluorescence effect, thus having good fluorescence sensing performance, so that the corrosion points of iron-containing metals can be detected as early as possible, improving the detection limit and detection sensitivity.

[0113] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A composition for detecting the corrosion of iron-containing metals, characterized in that, It includes a compound, an epoxy resin and a curing agent; Among them, the compound is used to detect the corrosion of iron-containing metals, and the structural formula of the compound is as follows: The preparation method of the composition for detecting the corrosion of iron-containing metals includes the following steps: S10: Add the compound into tetrahydrofuran to obtain a compound solution; S20: Mix the compound solution with the epoxy resin, and after evaporation and drying, obtain a mixture; S30: Add the curing agent to the mixture to obtain the composition for detecting the corrosion of iron-containing metals.

2. The composition for detecting the corrosion of ferrous metals according to claim 1, wherein In the composition for detecting the corrosion of iron-containing metals, the mass percentage of the compound is (0.1-1)‰.

3. The composition for detecting the corrosion of iron-containing metals according to claim 1, wherein In step S10: Add 4-20 mg of the compound to every 1 mL of tetrahydrofuran.

4. The composition for detecting the corrosion of iron-containing metals according to claim 1, wherein In step S20: Add 8-20 g of epoxy resin to every 1 mL of the compound solution.

5. The composition for detecting the corrosion of ferrous metals according to claim 1, characterized in that, In step S20: The temperature of evaporation and drying is 60-70 °C; and / or, The time of evaporation and drying is 1-3 h.

6. An iron-containing metal-coated part, characterized in that, It includes: A metal substrate containing iron elements; And, A composition coating for detecting the corrosion of iron-containing metals, provided on the upper side of the metal substrate, and the composition coating for detecting the corrosion of iron-containing metals includes the composition for detecting the corrosion of iron-containing metals as described in claim 1 or 2.

7. The iron-containing metal coated part as described in claim 6, characterized in that It further includes an anti-corrosion coating, wherein, The anti-corrosion coating is provided on the side of the composition coating for detecting the corrosion of iron-containing metals facing away from the metal substrate; and / or, The thickness of the composition coating for detecting the corrosion of iron-containing metals is 100-300 μm.

8. A detection method for pitting corrosion of iron-containing metals, characterized in that, It includes the following steps: Use the iron-containing metal coated part as described in claim 6 or 7; Perform fluorescence quenching detection on the iron-containing metal coated part under an ultraviolet lamp; Judge whether pitting corrosion occurs on the metal according to the detection result.

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