Method for detecting the leakage protection performance of a coolant corrosion protection film

Abstract

The present application relates to a kind of detection of cooling liquid anticorrosive film leakage protection performance method, the detection of cooling liquid anticorrosive film leakage protection performance method includes: providing sample to be measured and reference sample;Reference sample is carried out electrochemical impedance test;To be measured sample is placed in cooling liquid, and corrosion test is carried out according to SH / T 0088, then electrochemical impedance test is carried out;The electrode resistance of reference sample is compared with the electrode resistance of sample to be measured, judges the leakage protection performance of cooling liquid anticorrosive film.The detection of cooling liquid anticorrosive film leakage protection performance method provided by the present application, by the design of detection process, with the aid of specific detection process, with reference sample as benchmark comparison, realizes the efficient detection of the leakage protection performance of cooling liquid anticorrosive film, provides anticorrosive film leakage protection performance test scheme for cooling liquid formula development, selection work, improves cooling liquid formula development and selection accuracy and provides support.

Description

Technical Field

[0001] This invention relates to the field of detection and analysis technology, specifically to a method for detecting the leakage protection performance of a coolant anti-corrosion film. Background Technology

[0002] Currently, the coolant used in new energy vehicles is still mainly based on ethylene glycol aqueous solution, accounting for more than 98% of the total. Theoretically, once the ratio of ethylene glycol to water is determined, the thermal conductivity, specific heat capacity, heat flux and other heat-related performance parameters of the coolant are determined, and the thermal conductivity is basically the same.

[0003] For example, CN108611062A discloses an automotive coolant, belonging to the chemical industry. This invention uses hexamethylenetetramine and 1-bromooctane as raw materials to synthesize a quaternary ammonium salt derivative. The nitrogen atoms in this derivative molecule contain lone pairs of electrons, so the ionized ions of the derivative molecule are protonated in acidic solutions. Through chemical adsorption between the nitrogen atoms and the metal, the corrosion resistance is enhanced. The addition of benzotriazole, with its multiple active adsorption centers in its molecular structure, results in excellent corrosion inhibition performance. It can adsorb onto the metal surface to form a uniform, thin film, preventing corrosion from harmful substances in the air and water. The quaternary ammonium salt derivative exhibits strong corrosion resistance in compounding experiments and helps normalize the solution pH. The quaternary ammonium salt derivative, compounded with triethanolamine, forms a gas-phase corrosion inhibitor that creates a dense protective film on the metal surface, delaying corrosion.

[0004] For example, CN108587577A discloses a method for preparing automotive engine coolant, belonging to the field of coolant technology. This invention uses graphene / silica as the wall material and imidazoline quaternary ammonium salt as the core material to prepare graphene / silica porous microcapsules loaded with corrosion inhibitors. This effectively blocks the passage of gas atoms such as water and oxygen. Even when exposed to an environment with an oxygen partial pressure as high as 10⁻⁴ mbar, graphene can still provide good protection for the metal substrate. The prepared coolant exhibits significantly improved corrosion resistance, forming a uniform, dense adsorption film with a rhombic crystalline structure on the metal surface, thus delaying the corrosion process. The advantages of this corrosion inhibitor coating method are low dosage, significant corrosion resistance, and slow release rate. During immersion, the corrosion inhibitor continuously diffuses to the exposed substrate surface and interacts with it to form a film, inhibiting substrate corrosion.

[0005] According to the corrosion protection mechanism of coolant, coolant inhibits metal corrosion by forming an anti-corrosion film on the metal surface of the cooling system. The formed anti-corrosion film adheres to the metal surface, reduces the corrosion rate, and simultaneously constitutes a resistive element, affecting the micro-current density and thus the electrolysis rate of the coolant, thereby affecting the overall vehicle safety. However, metal resistance is tested with an ohmmeter, but the anti-corrosion film is only at the micrometer level, and the ohmmeter cannot respond to the resistance value of the anti-corrosion film, making it impossible to measure the resistance of the anti-corrosion film. In other words, there is no test method in the field of coolant testing specifically for the leakage protection performance of the anti-corrosion film of coolant, resulting in a lack of dimensions for coolant formulation screening and no examination of the impact on electrical safety. Therefore, there is an urgent need to develop a test method for testing the leakage protection performance of the anti-corrosion film of coolant to improve the accuracy of coolant leakage protection performance evaluation. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for testing the leakage protection performance of coolant anti-corrosion film, so as to solve the problems of poor detection effect and unstable detection when testing the leakage protection performance of coolant anti-corrosion film in the prior art.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] This invention provides a method for testing the leakage protection performance of a coolant anti-corrosion film, the method comprising:

[0009] Provide the sample to be tested and the reference sample;

[0010] Electrochemical impedance spectroscopy was performed on the reference sample;

[0011] The sample to be tested was placed in a coolant and subjected to a corrosion test in accordance with SH / T 0088, followed by an electrochemical impedance spectroscopy test.

[0012] By comparing the electrode resistance of the reference sample and the electrode resistance of the sample under test, the leakage protection performance of the coolant anti-corrosion film can be determined.

[0013] The method for testing the leakage protection performance of coolant anti-corrosion film provided by this invention achieves efficient testing of the leakage protection performance of coolant anti-corrosion film by designing a specific testing process and comparing it with a reference sample. This provides a testing scheme for the leakage protection performance of anti-corrosion film for coolant formulation development and selection, and supports the improvement of the accuracy of coolant formulation development and selection.

[0014] As a preferred technical solution of the present invention, the test sample and the reference sample have the same composition.

[0015] As a preferred technical solution of the present invention, the test sample and the reference sample are subjected to a first alcohol wash, a first polishing, a second polishing, a second alcohol wash and drying in sequence before testing.

[0016] As a preferred embodiment of the present invention, the first alcohol washing time is 2-30 min.

[0017] As a preferred technical solution of the present invention, the first polishing is polishing with 180 grit sandpaper;

[0018] Preferably, the second polishing is performed using 240-grit sandpaper.

[0019] As a preferred embodiment of the present invention, the second alcohol washing time is 1-5 minutes.

[0020] As a preferred technical solution of the present invention, the drying temperature is 80-150℃.

[0021] As a preferred embodiment of the present invention, the drying time is 2-3 hours.

[0022] As a preferred embodiment of the present invention, the volume concentration of the coolant in the corrosion test is 40-60%.

[0023] As a preferred embodiment of the present invention, the electrochemical impedance spectroscopy test is performed using a three-electrode system.

[0024] Compared with existing technical solutions, the present invention has the following beneficial effects:

[0025] (1) The detection scheme provided by the present invention can achieve the purpose of testing the leakage protection performance of the coolant anti-corrosion film, and solves the problem that the existing technology cannot verify the leakage protection performance of the coolant anti-corrosion film.

[0026] (2) The testing scheme provided by the present invention provides a test scheme for the leakage protection performance of the anti-corrosion film for coolant formulation development and selection, improves the accuracy of coolant formulation development and selection, and reduces the vehicle safety risk caused by the low resistance of the coolant anti-corrosion film. Attached Figure Description

[0027] Figure 1 This is an assembly diagram illustrating the method for accelerating the corrosion of two samples in an embodiment of the present invention;

[0028] Figure 2 This is an assembly diagram illustrating how to accelerate the corrosion of one sample in an embodiment of the present invention.

[0029] In the figure: 1-sample, 2-first metal washer, 3-insulating washer, 4-second metal washer, 5-metal nut, 6-metal rod.

[0030] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims. Detailed Implementation

[0031] To better illustrate the present invention and facilitate understanding of its technical solutions, typical but non-limiting embodiments of the present invention are as follows:

[0032] This embodiment provides a method for testing the leakage protection performance of a coolant anti-corrosion film, the method comprising:

[0033] Provide the sample to be tested and the reference sample;

[0034] Electrochemical impedance spectroscopy was performed on the reference sample;

[0035] The sample to be tested was placed in a coolant and subjected to a corrosion test in accordance with SH / T 0088, followed by an electrochemical impedance spectroscopy test.

[0036] By comparing the electrode resistance of the reference sample and the electrode resistance of the sample under test, the leakage protection performance of the coolant anti-corrosion film can be determined.

[0037] Specifically, the test sample and the reference sample have the same composition.

[0038] Specifically, both the test sample and the reference sample are subjected to a first alcohol wash, a first polishing, a second polishing, a second alcohol wash, and drying in sequence before testing.

[0039] In this invention, the alcohols used in the first and second alcohol washes are alcohols commonly used as detergents in the art, such as ethanol, ethylene glycol, propanol, methanol, etc.

[0040] In this invention, corrosion testing can accelerate the formation of a corrosion film by specifically assembling the test samples. For example, it can utilize electrochemical principles to assemble the sample with a metal material, achieving rapid corrosion film formation through a spontaneous electrochemical process. Furthermore, it can process multiple samples at once, thereby improving detection efficiency. For example, when using YL12 cast aluminum alloy and 45# steel as sample 1, such as... Figure 1 As shown, both are assembled together on a metal rod 6 (e.g., brass), with a first metal washer 2 separating them to prevent interference while also creating an electronic pathway. A metal nut 5 is used for fixation. A second metal washer 4 and an insulating washer 3 are placed between the metal nut 5 and sample 1, with the insulating washer 3 adjacent to sample 1. When there are more than two samples, simply add sample 1 and the first metal washer 2 accordingly.

[0041] In this process, the materials of the metals used in the assembly can be selected reasonably based on the actual required corrosion rate. For example, the corrosion rate of the first metal washer 2, the second metal washer 4, the metal nut 5, and the metal rod 6 should be less than that of sample 1 to ensure the stability of the corrosion assembly.

[0042] The insulating gaskets used in the assembly are made of insulating materials, such as organic polymer materials, specifically polytetrafluoroethylene insulating gaskets.

[0043] Furthermore, when there is only one sample, simply remove one sample and the first metal gasket between the two samples. Figure 2 As shown.

[0044] The first alcohol washing time is 2-30 min, for example, it can be 2 min, 4 min, 6 min, 8 min, 10 min, 12 min, 14 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min or 30 min, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0045] The first polishing process involves using 180-grit sandpaper.

[0046] In this invention, the purpose of the first polishing is to remove surface defects and rust from the sample.

[0047] The second polishing process involves using 240-grit sandpaper.

[0048] In this invention, the purpose of the second polishing is to polish the sample until there are no obvious defects on the surface, such as a surface roughness Ra of 1-3 μm.

[0049] The second alcohol washing time is 1-5 minutes, for example, it can be 1 minute, 2 minutes, 3 minutes, 4 minutes or 5 minutes, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0050] The drying temperature is 80-150℃, for example, it can be 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃ or 150℃, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0051] The drying time is 2-3 hours, for example, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours or 3 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0052] Specifically, the electrochemical impedance spectroscopy test is performed using a three-electrode system.

[0053] Specifically, the volume concentration of the coolant in the corrosion test is 40-60%, for example, it can be 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, or 60%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also acceptable.

[0054] In this invention, the coolant used in the corrosion test is a coolant commonly used in the art that can form an anti-corrosion film on materials in contact with the coolant, such as the coolants disclosed in CN108611062A and CN108587577A.

[0055] In this invention, the three-electrode system refers to a three-electrode two-circuit system: the three electrodes are the working electrode, the reference electrode, and the counter electrode; the two circuits are the test circuit composed of the working electrode and the reference electrode and the polarization circuit composed of the working electrode and the auxiliary electrode, respectively. For example, a silver-silver chloride electrode is selected as the reference electrode and a platinum electrode is selected as the counter electrode.

[0056] Furthermore, to illustrate the superior detection effect of the method for detecting the leakage protection performance of the coolant anti-corrosion film of the present invention, a practical example is used for explanation, as follows:

[0057] Example 1

[0058] This embodiment provides a method for testing the leakage protection performance of the coolant anti-corrosion film, as detailed below:

[0059] S1. Metal Sample Preparation: Based on the metal materials used in the cooling system of new energy vehicles, YL12 cast aluminum alloy and 45# steel were selected as experimental materials. A total of four samples were prepared: two YL12 cast aluminum alloy samples (one as a reference sample and one as the test sample) and two 45# steel samples (one as a reference sample and one as the test sample). The sample dimensions were 50mm × 25mm × 2mm, with a Φ7mm through hole in the center. The surface of the metal samples was cleaned with anhydrous ethanol for 30 minutes to remove oil stains. After drying, 180-grit sandpaper was used to remove surface defects and rust. Then, 240-grit sandpaper was used to polish the surface until there were no obvious defects, with a surface roughness of 1μm. The polished metal samples were then picked up with tweezers, rinsed in anhydrous ethanol for 1 minute, and placed in a desiccator to dry at 150℃ for 2 hours.

[0060] S2. The metal samples tested after S1 treatment included: one YL12 cast aluminum alloy sample and one 45# steel sample, used as reference samples for electrochemical impedance spectroscopy. A three-electrode system was constructed using a 50% (v / v) ethylene glycol aqueous solution as the test solution, a silver-silver chloride electrode as the reference electrode, a platinum electrode as the counter electrode, and the S1-treated metal sample as the working electrode. The electrochemical impedance of the metal samples was tested at a potential of 6V and a frequency of 10 Hz. 5 Hz~10 -2 The equivalent circuit method was used to process the data at Hz to obtain the metal electrode resistance of each metal sample.

[0061] S3. Prepare an anti-corrosion film on the surface of the metal sample from S1: Assemble the metal sample group in the following order: insulating gasket, YL12 cast aluminum alloy, steel gasket, 45# steel, insulating gasket. Place the group in the stainless steel storage tank of the battery coolant simulated corrosion test bench. The coolant is "Coolant A" with a volume fraction of 40%. Conduct a 1064-hour simulated corrosion test according to SH / T0088. After the test, remove the metal sample and clean it with anhydrous ethanol as soon as possible. During the cleaning process, gently brush the surface of the metal sample with a soft brush to remove any adhering substances. After cleaning, place the metal sample in a desiccator to dry for 2 hours.

[0062] S4. Electrochemical impedance spectroscopy of the metal sample treated in S3: A three-electrode system was constructed using a 50% (v / v) ethylene glycol aqueous solution as the test solution, a silver-silver chloride electrode as the reference electrode, a platinum electrode as the counter electrode, and the metal sample treated in S3 as the working electrode. The electrochemical impedance spectroscopy of the metal sample was tested at a potential of 6V and a frequency of 10 Hz. 5 Hz~10 -2 The equivalent circuit method was used to process the data at Hz to obtain the metal electrode resistance of each metal sample.

[0063] S5. Obtain the difference in metal electrode resistance between the metal sample (test sample) and the reference sample measured in S2 and S4, and determine the leakage protection performance of the coolant anti-corrosion film.

[0064] Based on the metal electrode resistance of the metal samples measured in S2 and S4, the difference in metal electrode resistance between the YL12 cast aluminum alloy sample and the No. 45 steel sample corresponding to "coolant A" is calculated, as shown in Table 1 below.

[0065] In this embodiment, coolant A is selected from the coolant of Example 2 of the prior art CN108587577A.

[0066] Example 2

[0067] This embodiment provides a method for testing the leakage protection performance of the coolant anti-corrosion film, as detailed below:

[0068] S1. Metal Sample Preparation: Based on the metal materials used in the cooling system of new energy vehicles, YL12 cast aluminum alloy and 45# steel were selected as experimental materials. A total of four samples were prepared: two YL12 cast aluminum alloy samples (one as a reference sample and one as the test sample) and two 45# steel samples (one as a reference sample and one as the test sample). The sample dimensions were 50mm × 25mm × 2mm, with a Φ7mm through hole in the center. The metal samples were cleaned with anhydrous ethanol for 5 minutes to remove oil stains. After drying, surface defects and rust were removed using 180-grit sandpaper. Then, the surface was polished with 240-grit sandpaper until there were no obvious defects, and the surface roughness was 3μm. The polished metal samples were then picked up with tweezers, rinsed in anhydrous ethanol for 5 minutes, and placed in a desiccator to dry at 80℃ for 3 hours.

[0069] S2. The metal samples tested after S1 treatment included: one YL12 cast aluminum alloy sample and one 45# steel sample, used as reference samples for electrochemical impedance spectroscopy. A three-electrode system was constructed using a 50% (v / v) ethylene glycol aqueous solution as the test solution, a silver-silver chloride electrode as the reference electrode, a platinum electrode as the counter electrode, and the S1-treated metal sample as the working electrode. The electrochemical impedance spectroscopy of the metal samples was tested at a potential of 6V and a frequency of 10 Hz. 5 Hz~10 -2 The equivalent circuit method was used to process the data at Hz to obtain the metal electrode resistance of each metal sample.

[0070] S3. Prepare an anti-corrosion film on the surface of the metal sample from S1. Assemble the metal sample group in the following order: insulating gasket, YL12 cast aluminum alloy, steel gasket, 45# steel, and insulating gasket again. Place the group in the stainless steel reservoir of the battery coolant simulated corrosion test bench. The coolant is "Coolant B" with a volume fraction of 60%. Conduct a 1064-hour simulated corrosion test according to SH / T0088. After the test, remove the metal sample and clean it with anhydrous ethanol as soon as possible. During cleaning, gently brush the surface of the metal sample with a soft brush to remove any adhering substances. After cleaning, place the metal sample in a desiccator to dry for 2 hours.

[0071] S4. Electrochemical impedance spectroscopy of the metal sample treated in S3: A three-electrode system was constructed using a 50% (v / v) ethylene glycol aqueous solution as the test solution, a silver-silver chloride electrode as the reference electrode, a platinum electrode as the counter electrode, and the metal sample treated in S3 as the working electrode. The electrochemical impedance spectroscopy of the metal sample was tested at a potential of 6V and a frequency of 10 Hz. 5 Hz~10 -2 The equivalent circuit method was used to process the data at Hz to obtain the metal electrode resistance of each metal sample.

[0072] S5. Obtain the difference in metal electrode resistance between the metal sample (test sample) and the reference sample measured in S2 and S4, and determine the leakage protection performance of the coolant anti-corrosion film.

[0073] Based on the metal electrode resistance of the metal samples measured in S2 and S4, the difference in metal electrode resistance between the YL12 cast aluminum alloy sample and the No. 45 steel sample corresponding to "coolant B" is calculated, as shown in Table 1 below.

[0074] The coolant B used in this embodiment is selected from the coolant shown in Example 2 of the prior art CN108611062A.

[0075] Table 1

[0076]

[0077]

[0078] As shown in the table above, the metal electrode resistance of the metal sample with the coolant anti-corrosion film (step S4) is greater than that of the metal sample without the coolant anti-corrosion film (step S2). This indicates that the coolant anti-corrosion film can increase the metal polarization impedance, reduce the influence of microcurrent on the electrode, reduce the risk of coolant electrolysis, and provide a certain degree of protection against leakage. However, different coolants exhibit different leakage protection capabilities. The difference in metal electrode resistance between the YL12 cast aluminum alloy sample and the 45 steel sample corresponding to "coolant B" is greater than that between the YL12 cast aluminum alloy sample and the 45 steel sample corresponding to "coolant A". This indicates that the resistance of the anti-corrosion film formed by "coolant B" is greater than that formed by "coolant A", meaning that the leakage protection performance of the anti-corrosion film formed by "coolant B" is better than that formed by "coolant A".

[0079] The present invention is described in detail through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0080] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0081] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0082] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for testing the leakage protection performance of a coolant anti-corrosion film, characterized in that, The method for detecting the leakage protection performance of the coolant anti-corrosion film includes: Provide the sample to be tested and the reference sample; Electrochemical impedance spectroscopy was performed on the reference sample; The sample to be tested was placed in a coolant and a corrosion test was conducted in accordance with SH / T 0088. After the corrosion test, the sample to be tested was cleaned and dried before electrochemical impedance spectroscopy. By comparing the electrode resistance of the reference sample and the electrode resistance of the sample under test, the leakage protection performance of the coolant anti-corrosion film can be determined.

2. The method for detecting the leakage protection performance of the coolant anti-corrosion film as described in claim 1, characterized in that, The test sample and the reference sample have the same composition.

3. The method for detecting the leakage protection performance of the coolant anti-corrosion film as described in claim 1 or 2, characterized in that, Before testing, both the test sample and the reference sample were subjected to a first alcohol wash, a first polishing, a second polishing, a second alcohol wash, and drying.

4. The method for detecting the leakage protection performance of the coolant anti-corrosion film as described in claim 3, characterized in that, The first alcohol wash time is 2-30 minutes.

5. The method for detecting the leakage protection performance of the coolant anti-corrosion film as described in claim 3, characterized in that, The first polishing process involves using 180-grit sandpaper.

6. The method for detecting the leakage protection performance of the coolant anti-corrosion film as described in claim 3, characterized in that, The second polishing process involves using 240-grit sandpaper.

7. The method for detecting the leakage protection performance of the coolant anti-corrosion film as described in claim 3, characterized in that, The second alcohol wash time is 1-5 minutes.

8. The method for detecting the leakage protection performance of the coolant anti-corrosion film as described in claim 3, characterized in that, The drying temperature is 80-150℃.

9. The method for detecting the leakage protection performance of the coolant anti-corrosion film as described in claim 3, characterized in that, The drying time is 2-3 hours.

10. The method for detecting the leakage protection performance of the coolant anti-corrosion film as described in claim 1, characterized in that, The volume concentration of the coolant in the corrosion test was 40-60%.

11. The method for detecting the leakage protection performance of the coolant anti-corrosion film as described in claim 1, characterized in that, The electrochemical impedance spectroscopy was performed using a three-electrode system.

Images