Method for simply and rapidly preparing high-corrosion-resistance carbon-based coating on metal surface

Abstract

The invention discloses a method for simply and rapidly preparing a high-corrosion-resistance carbon-based coating on a metal surface, and relates to a method for preparing a high-corrosion-resistance carbon-based coating. The invention aims to solve the problems of high deposition voltage, long preparation period and high energy consumption in the existing method for preparing the carbon-based coating on the metal surface by adopting a liquid-phase electrochemical deposition method. According to the method, the aqueous solution of the organic reagent is adopted as the electrolyte, and the conductive salt such as KCl or NaCl is added to enhance the conductivity of the electrolyte, so that the dosage of the organic reagent is reduced, the deposition rate is increased, and the deposition time is greatly shortened while the deposition voltage is reduced. The thickness of the carbon-based coating can be regulated and controlled by changing the concentration of the carbon source or controlling the deposition time, the high-corrosion-resistance carbon-based coating with a continuous and uniform structure is obtained by innovatively adopting a continuous electrolyte supplementing mode, and the prepared coating is continuous, compact in structure, high in sp3 bond proportion and relatively high in corrosion resistance.

Description

Technical Field

[0001] The present invention relates to a method for preparing a highly corrosion-resistant carbon-based coating. Background Art

[0002] Carbon-based coatings have unique and adjustable combined properties, such as high hardness and wear resistance, chemical resistance, and good tribological properties. Depositing a carbon-based coating on the surface of a metal material can not only protect the metal material and extend its service life, but also regulate certain properties of the metal material by controlling the ratio of sp 3 hybrid carbon bonds and sp 2 hybrid carbon bonds to meet its performance requirements in different environments.

[0003] Carbon-based coatings are mainly prepared by chemical vapor deposition (CVD) and physical vapor deposition (PVD). Patent CN1271242C uses methane, a hydrocarbon gas, as a carbon source and deposits a diamond-like film with relatively high hardness by using plasma decomposition combined with high-energy ion bombardment technology. Patent CN117448775A uses a carbon-containing gas as a carbon source, ionizes the carbon source gas by means of discharge plasma treatment, and prepares an amorphous carbon film with fewer defects and better film-substrate adhesion on a metal substrate. This film layer has high conductivity and high corrosion resistance. High-quality carbon-based coatings can be obtained by the above methods. However, these methods require complex and expensive equipment, are difficult to form large-area films, and have a long deposition time, which to a certain extent limits the further development of carbon-based coatings.

[0004] Most of the thin film materials deposited by physical vapor deposition can also be synthesized electrochemically in liquid phase. Compared with physical vapor deposition, the liquid phase electrochemical deposition method has the advantages of simple equipment, low cost, low deposition temperature, and the ability to form films on a large area, making it suitable for industrial production. In 1992, Namba first attempted to deposit diamond-like carbon (DLC) coatings using a liquid phase electrochemical method with pure ethanol as the carbon source, providing a new strategy for the study of carbon-based coatings. (Namba Y. Attempt to grow diamond phase carbon films from an organic solution[J]. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 1992, 10(5): 3368-3370.) Since then, researchers have carried out a large number of studies on the preparation of diamond-like films by liquid phase electrochemical deposition. The DLC coatings obtained by traditional liquid phase electrochemical deposition mostly use pure organic reagents with extremely low conductivity as electrolytes, so high voltages (1000-2000V) and small electrode gaps (~7mm) are always required, and the deposition time is long, even up to more than ten hours. For example, Mousa et al. prepared diamond-like films by liquid phase electrochemical deposition at a high voltage of 1200V using analytical grade methanol as the carbon source (Mousa AM, Ismail R A, Hassan M A. Preparation and Characteristics Study of Diamond-Like Carbon (DLC) Film on-Si Substrates by Electrolysis of Methanol[J]. Engineering and Technology Journal, 2016, 34(5B): 703-710.). Yu et al. deposited hydrogenated amorphous carbon films by the liquid phase method using analytical grade acetonitrile as the carbon source at a high voltage of 1200V for 10h (Yu Y, Liu S, Zhang J. Cathode electrodeposition and characterization of Ru nanoparticles doped a-CNx:H composite films[J]. Diamond and related materials, 2010, 19(5-6): 661-664.). Although the above methods for preparing carbon-based coatings require simpler equipment and lower costs compared with physical vapor deposition, the coating deposition voltage is high, the preparation cycle is long, and the energy consumption is large. Summary of the Invention

[0005] In order to solve the problems of high deposition voltage, long preparation period and high energy consumption existing in the preparation of carbon-based coatings on metal surfaces by the liquid-phase electrochemical deposition method, the present invention proposes a method for simply and rapidly preparing a highly corrosion-resistant carbon-based coating on a metal surface.

[0006] The present invention uses an aqueous solution of an organic reagent as the electrolyte and adds a conductive salt such as KCl or NaCl to enhance the conductivity of the electrolyte, reduces the amount of the organic reagent used, improves the deposition rate, and while reducing the deposition voltage, greatly shortens the deposition time. The thickness of the carbon-based coating can be regulated by changing the carbon source concentration or controlling the deposition time. The innovative method of continuously supplementing the electrolyte is adopted to obtain a highly corrosion-resistant carbon-based coating with continuous and uniform structure. The prepared coating is continuous, has a dense structure, a high proportion of sp3 bonds, and has high corrosion resistance.

[0007] The method for simply and rapidly preparing a highly corrosion-resistant carbon-based coating on a metal surface according to the present invention is carried out according to the following steps:

[0008] I. Pre-treat the metal sample by grinding, polishing and cleaning.

[0009] When cleaning the metal sample, deionized water, acetone and alcohol are used for cleaning in sequence, and finally drying is carried out.

[0010] II. Prepare an electrolyte containing a carbon source and a conductive salt, and fill the electrolyte into the reaction vessel of the deposition system.

[0011] The carbon source in the electrolyte is acetonitrile, and the mass fraction of the carbon source in the electrolyte is 20%-40%.

[0012] The conductive salt in the electrolyte is KCl or NaCl.

[0013] The mass fraction of the conductive salt in the electrolyte is 0.3%-0.4%.

[0014] III. Install the pre-treated metal sample and the anode electrode in the reaction vessel of the deposition system, and immerse the metal sample and the anode electrode in the electrolyte.

[0015] IV. Connect the metal sample to the cathode of the power supply, and connect the anode electrode to the anode of the power supply. Turn on the circulating cooling device and the electrolyte stirring device in the deposition system, start the DC power supply to deposit the carbon-based coating, apply a voltage of 200 - 300V, and maintain it for 40 - 80 minutes to obtain a carbon-based coating with a thickness of 2 - 5μm. During the deposition of the carbon-based coating, when the reaction proceeds for 10 - 15 minutes, supplement the electrolyte, and the supplement amount is 20% - 25% of the volume of the original electrolyte; then supplement the electrolyte every 10 - 15 minutes, and the supplement amount is 20% - 25% of the volume of the original electrolyte. During the deposition of the carbon-based coating, supplement the electrolyte prepared in step II to ensure that the metal sample and the anode electrode are immersed in the electrolyte, preventing the interruption of deposition due to carbon source loss during the long-term deposition process.

[0016] The principle of the present invention is as follows:

[0017] By applying a DC voltage between the metal sample and the anode electrode, an electric field is generated between the two electrodes, which promotes the polarization and even ionization of organic molecules, and an electrochemical reaction occurs on the surface of the sample to generate carbon fragments, and gradually form a continuous carbon-based thin film. The specific reaction process is as follows:

[0018] Under the action of the applied electric field, acetonitrile molecules are induced to become energy molecules and move towards the cathode surface; at the same time, water molecules are electrolyzed to produce hydrogen ions, which are adsorbed on the cathode surface.

[0019]

[0020] H2O → +H + +OH - (2)

[0021] Under the action of the cathode electric field, when the energy reaches a certain value, the polarized acetonitrile molecules ionize to generate CH3+, and then, at the active reaction sites of the cathode, CH3+ and H+ respectively obtain electrons and generate active methyl (CH3·) and hydrogen radicals (H·);

[0022]

[0023] H + +e - →H· (5)

[0024] On the surface of the substrate sample, hydrogen-based radicals assist the dehydrogenation reaction between methyl groups to rapidly nucleate and form a carbon network;

[0025] H· + 2CH3· → H2 + CH2=CH2 (6)

[0026] The "chemical pump" described in the non-equilibrium thermodynamics coupling model transfers carbon atoms from the graphite phase to the diamond phase, forming a DLC coating composed of sp2-C and sp3-C;

[0027]

[0028] The beneficial effects of the present invention are as follows:

[0029] 1. Since the commonly used pure organic reagents for preparing carbon-based thin films do not contain freely moving ions or electrons, their electrical conductivity is very poor, and high-voltage external conditions are often required to polarize and ionize organic molecules. Compared with the traditional liquid-phase deposition method, the present invention uses an electrolyte system containing a certain volume of carbon source. After adding deionized water, the amount of organic reagent used is reduced, and the addition of conductive salts enhances the electrical conductivity of the solution, improves the deposition rate, and reduces the external conditions for polarizing and ionizing organic molecules. Therefore, the amount of organic reagent used is reduced, the deposition rate is increased, the deposition voltage is significantly reduced, and the deposition time is greatly shortened.

[0030] 2. The present invention uses acetonitrile as the carbon source, and regulates the relative content of sp2 hybrid carbon bonds and sp3 hybrid carbon bonds in the coating by changing the carbon source concentration and experimental parameters, so as to achieve the purpose of regulating the coating performance. The required equipment system is simple, the deposition voltage is low, the energy consumption is low, and a uniform and dense carbon-based coating can be quickly prepared on the surface of metal materials. The surface of the coating is dense and uniform, which hinders the contact between corrosive media and metal samples, and has high corrosion resistance. Compared with the untreated metal specimen without a deposited coating, the corrosion current density of the carbon-based coating prepared by the present invention is reduced, and the corrosion potential and polarization resistance are both improved.

[0031] 3. Compared with the conventional chemical vapor deposition method, the present invention has simple equipment, low cost, convenient operation, and is easy to form a film on a large area. Description of the Drawings

[0032] Figure 1 is the Raman spectrum of the carbon-based coating obtained in Example 1;

[0033] Figure 2 is the XPS C1s spectrum of the carbon-based coating obtained in Example 1;

[0034] Figure 3 is the polarization curve and EIS diagram of the metal substrate and the carbon-based coating obtained in Example 1. Detailed Embodiments

[0035] The technical solution of the present invention is not limited to the following specific embodiments, and also includes any reasonable combination between the specific embodiments.

[0036] Specific Embodiment 1: The method for simply preparing a highly corrosion-resistant carbon-based coating on the metal surface in this embodiment is carried out according to the following steps:

[0037] 1. Pretreat the metal sample by polishing, buffing, and cleaning;

[0038] When cleaning the metal sample, deionized water, acetone, and alcohol are used for cleaning in sequence, and finally drying is performed;

[0039] 2. Prepare an electrolyte solution containing a carbon source and a conductive salt, and fill the electrolyte solution into the reaction vessel of the deposition system;

[0040] The carbon source in the electrolyte solution is acetonitrile, and the mass fraction of the carbon source in the electrolyte solution is 20% - 40%;

[0041] The conductive salt in the electrolyte solution is KCl or NaCl;

[0042] The mass fraction of the conductive salt in the electrolyte solution is 0.3% - 0.4%;

[0043] 3. Install the metal sample pretreated in step 1 and the anode electrode in the reaction vessel of the deposition system, and immerse the metal sample and the anode electrode in the electrolyte solution;

[0044] 4. Connect the metal sample to the cathode of the power supply, connect the anode electrode to the anode of the power supply, turn on the circulating cooling device and the electrolyte stirring device in the deposition system, start the DC power supply to deposit the carbon-based coating, apply a voltage of 200 - 300V, and maintain it for 40 - 80 minutes to obtain a carbon-based coating with a thickness of 2 - 5μm; during the deposition of the carbon-based coating, when the reaction proceeds for 10 - 15 minutes, supplement the electrolyte, and the supplement amount is 20% - 25% of the volume of the original electrolyte; then supplement the electrolyte every 10 - 15 minutes, and the supplement amount is 20% - 25% of the volume of the original electrolyte; during the deposition of the carbon-based coating, supplement the electrolyte prepared in step 2 to ensure that the metal sample and the anode electrode are immersed in the electrolyte solution, and prevent the interruption of deposition due to the loss of the carbon source during the long-term deposition process.

[0045] 1. Commonly used pure organic reagents for preparing carbon-based thin films have very poor conductivity because they do not contain freely moving ions or electrons, and high voltage external conditions are often required to polarize and ionize organic molecules. Compared with the traditional liquid-phase deposition method, in this embodiment, an electrolyte solution system containing a certain volume of carbon source is used in the present invention. After adding deionized water, the amount of organic reagent used is reduced, and the addition of the conductive salt enhances the conductivity of the solution, improves the deposition rate, and reduces the external conditions for polarizing and ionizing organic molecules. Therefore, the amount of organic reagent used is reduced, the deposition rate is increased, and while significantly reducing the deposition voltage, the deposition time is greatly shortened.

[0046] 2. In this embodiment, acetonitrile is used as the carbon source. By changing the carbon source concentration and experimental parameters, the relative content of sp2 hybrid carbon bonds and sp3 hybrid carbon bonds in the coating is regulated, thereby achieving the purpose of regulating the coating performance. The required equipment system is simple, the deposition voltage is low, and the energy consumption is low. A uniform and dense carbon-based coating can be rapidly prepared on the surface of metal materials. The surface of the coating is dense and uniform, which hinders the contact between corrosive media and metal samples, and has high corrosion resistance. Compared with the untreated metal specimen without the deposited coating prepared by the present invention, the corrosion current density is reduced, and the corrosion potential and polarization resistance are both improved.

[0047] 3. Compared with the conventional chemical vapor deposition method, the equipment in this embodiment is simple, the cost is low, the operation is convenient, and it is easy to form a film on a large area.

[0048] Specific Embodiment 2: The difference between this embodiment and Specific Embodiment 1 is that: the material of the metal sample in Step 1 is carbon steel, stainless steel, titanium alloy or aluminum alloy.

[0049] Specific Embodiment 3: The difference between this embodiment and Specific Embodiment 1 or 2 is that: the shape of the metal sample in Step 1 is a round sheet, a cuboid or a cylinder.

[0050] Specific Embodiment 4: The difference between this embodiment and any one of Specific Embodiments 1 to 3 is that: the carbon source in the electrolyte in Step 2 is acetonitrile, and the mass fraction of the carbon source in the electrolyte is 30%.

[0051] Specific Embodiment 5: The difference between this embodiment and any one of Specific Embodiments 1 to 4 is that: the mass fraction of the conductive salt in the electrolyte in Step 2 is 0.35%.

[0052] Specific Embodiment 6: The difference between this embodiment and any one of Specific Embodiments 1 to 5 is that: the anode electrode in Step 3 is a graphite plate or a Pt metal sheet.

[0053] Specific Embodiment 7: The difference between this embodiment and any one of Specific Embodiments 1 to 6 is that: the distance between the metal sample and the anode electrode in Step 3 is 10 - 12 mm.

[0054] Specific Embodiment 8: The difference between this embodiment and any one of Specific Embodiments 1 to 7 is that: in Step 4, the metal sample is connected to the cathode of the power supply, the anode electrode is connected to the anode of the power supply, the circulating cooling device and the electrolyte stirring device in the deposition system are turned on, the DC power supply is started for the deposition of the carbon-based coating, a voltage of 260 V is applied, and it is maintained for 60 min to obtain a carbon-based coating with an average thickness of 2.3 μm; during the deposition of the carbon-based coating, the electrolyte is replenished when the reaction proceeds for 15 min, and the replenishment amount is 25% of the volume of the original electrolyte; thereafter, the electrolyte is replenished every 15 min, and the replenishment amount is 25% of the volume of the original electrolyte.

[0055] Embodiment 9 in detail: The difference between this embodiment and any one of Embodiments 1 to 8 is as follows: In Step 4, the metal sample is connected to the cathode of the power supply, and the anode electrode is connected to the anode of the power supply. The circulating cooling device and the electrolyte stirring device in the deposition system are turned on, and the DC power supply is started to deposit the carbon-based coating. A voltage of 240 V is applied and maintained for 60 min to obtain a carbon-based coating with an average thickness of 2.1 μm. During the deposition of the carbon-based coating, when the reaction proceeds for 15 min, the electrolyte is replenished, and the replenishment amount is 25% of the volume of the original electrolyte; thereafter, the electrolyte is replenished every 15 min, and the replenishment amount is 25% of the volume of the original electrolyte.

[0056] Embodiment 10 in detail: The difference between this embodiment and any one of Embodiments 1 to 9 is as follows: In Step 4, the metal sample is connected to the cathode of the power supply, and the anode electrode is connected to the anode of the power supply. The circulating cooling device and the electrolyte stirring device in the deposition system are turned on, and the DC power supply is started to deposit the carbon-based coating. A voltage of 260 V is applied and maintained for 60 min to obtain a carbon-based coating with an average thickness of 2.2 μm. During the deposition of the carbon-based coating, when the reaction proceeds for 15 min, the electrolyte is replenished, and the replenishment amount is 25% of the volume of the original electrolyte; thereafter, the electrolyte is replenished every 15 min, and the replenishment amount is 25% of the volume of the original electrolyte.

[0057] Example 1:

[0058] The method for simply and rapidly preparing a highly corrosion-resistant carbon-based coating on the metal surface in this example is carried out according to the following steps:

[0059] I. The metal sample is subjected to pretreatment of grinding, polishing and cleaning;

[0060] When the metal sample is cleaned, it is successively cleaned with deionized water, acetone and alcohol, and finally dried;

[0061] The material of the metal sample is stainless steel;

[0062] The shape of the metal sample is a disc;

[0063] II. An electrolyte containing a carbon source and a conductive salt is prepared, and the electrolyte is filled into the reaction vessel of the deposition system;

[0064] The carbon source in the electrolyte is acetonitrile, and the mass fraction of the carbon source in the electrolyte is 30%;

[0065] The conductive salt in the electrolyte is NaCl; the mass fraction of the conductive salt in the electrolyte is 0.35%;

[0066] III. The metal sample pretreated in Step I and the anode electrode are installed in the reaction vessel of the deposition system, and the metal sample and the anode electrode are immersed in the electrolyte;

[0067] The anode electrode is a graphite plate;

[0068] The distance between the metal sample and the anode electrode is 11 mm;

[0069] IV. Connect the metal sample to the cathode of the power supply, connect the anode electrode to the anode of the power supply, turn on the circulating cooling device and the electrolyte stirring device in the deposition system, start the DC power supply to deposit the carbon-based coating, apply a voltage of 260 V, and keep it for 60 min to obtain a carbon-based coating with an average thickness of 2.3 μm; during the deposition of the carbon-based coating, when the reaction proceeds for 15 min, supplement the electrolyte, and the supplement amount is 25% of the volume of the original electrolyte; then supplement the electrolyte every 15 min, and the supplement amount is 25% of the volume of the original electrolyte.

[0070] Figure 1 is the Raman spectrum of the carbon-based coating obtained in Example 1; Figure 1 It shows that the carbon-based coating was successfully prepared. Peaks around 1350 cm -1 and 1600 cm -1 are typical characteristic peaks of the diamond-like coating, indicating that this carbon-based coating is a diamond-like coating. Figure 2 is the XPS C1s spectrum of the carbon-based coating obtained in Example 1; the XPS of Example 1 was used to determine sp3-C and sp2-C in the diamond-like coating. The C1s spectrum was resolved into 5 peaks by Gaussian fitting, which were attributed to sp2-C, sp3-C, C-O, C=O, and C-Cr bonds respectively. The ratio of the peak area of sp3-C to the total area of carbon peaks is the content of sp3-C in the coating. The content of sp3-C in the carbon-based coating deposited for 60 min is 63.63%. Figure 3 are the polarization curve and EIS diagram of the metal substrate and the carbon-based coating obtained in Example 1. Among them, Figure a is the polarization curve of the uncoated (untreated sample) and the carbon-based coating (60 min) obtained in Example 1. The vertical axis is the corrosion potential, and the horizontal axis is the logarithm of the corrosion current density. The larger the corrosion potential and the smaller the corrosion current density, the better the corrosion resistance. Figure (a) shows that the deposition of the carbon-based coating improves the corrosion resistance of the metal substrate. Figures b, c, and d are the Nyquist diagram, Bode diagram, and phase angle of the electrochemical impedance respectively. In Figure b, the larger the radius of the arc, the better the corrosion resistance. Figures c and d are used to assist in proving the conclusion of Figure b. The larger the vertical axis of Figures c and d, the better the corrosion resistance. Figure 3 It shows that the carbon-based coating obtained in Example 1 has better corrosion resistance compared with the untreated sample.

[0071] Example 2:

[0072] The method for simply and rapidly preparing a highly corrosion-resistant carbon-based coating on the metal surface in this example is carried out according to the following steps:

[0073] 1. Pre-treat the metal sample by grinding, polishing and cleaning;

[0074] When cleaning the metal sample, wash it successively with deionized water, acetone and alcohol, and finally dry it;

[0075] The material of the metal sample is stainless steel;

[0076] The shape of the metal sample is a round sheet;

[0077] 2. Prepare an electrolyte containing a carbon source and a conductive salt, and fill the electrolyte into the reaction vessel of the deposition system;

[0078] The carbon source in the electrolyte is acetonitrile, and the mass fraction of the carbon source in the electrolyte is 30%;

[0079] The conductive salt in the electrolyte is NaCl; the mass fraction of the conductive salt in the electrolyte is 0.35%;

[0080] 3. Install the pre-treated metal sample and the anode electrode in the reaction vessel of the deposition system, and immerse the metal sample and the anode electrode in the electrolyte;

[0081] The anode electrode is a graphite plate;

[0082] The distance between the metal sample and the anode electrode is 11 mm;

[0083] 4. Connect the metal sample to the cathode of the power supply and the anode electrode to the anode of the power supply. Turn on the circulating cooling device and the electrolyte stirring device in the deposition system, start the DC power supply to deposit the carbon-based coating, apply a voltage of 240 V, and maintain it for 60 min to obtain a carbon-based coating with an average thickness of 2.1 μm; during the deposition of the carbon-based coating, when the reaction proceeds for 15 min, supplement the electrolyte, and the supplement amount is 25% of the volume of the original electrolyte; then supplement the electrolyte every 15 min, and the supplement amount is 25% of the volume of the original electrolyte.

[0084] Example 3:

[0085] The method for simply and rapidly preparing a highly corrosion-resistant carbon-based coating on the metal surface in this example is carried out according to the following steps:

[0086] 1. Pre-treat the metal sample by grinding, polishing and cleaning;

[0087] When cleaning the metal sample, wash it successively with deionized water, acetone and alcohol, and finally dry it;

[0088] The material of the metal sample is stainless steel;

[0089] The shape of the metal sample is a round sheet;

[0090] II. Prepare an electrolyte containing a carbon source and a conductive salt, and fill the electrolyte into the reaction vessel of the deposition system;

[0091] The carbon source in the electrolyte is acetonitrile, and the mass fraction of the carbon source in the electrolyte is 20%;

[0092] The conductive salt in the electrolyte is NaCl; the mass fraction of the conductive salt in the electrolyte is 0.35%;

[0093] III. Install the pretreated metal sample and the anode electrode in the reaction vessel of the deposition system, and immerse the metal sample and the anode electrode in the electrolyte;

[0094] The anode electrode is a graphite plate;

[0095] The distance between the metal sample and the anode electrode is 11 mm;

[0096] IV. Connect the metal sample to the cathode of the power supply and the anode electrode to the anode of the power supply. Turn on the circulating cooling device and the electrolyte stirring device in the deposition system, start the DC power supply to deposit the carbon-based coating, apply a voltage of 260 V, and maintain it for 60 min to obtain a carbon-based coating with an average thickness of 2.2 μm; during the deposition of the carbon-based coating, when the reaction proceeds for 15 min, supplement the electrolyte, and the supplement amount is 25% of the volume of the original electrolyte; thereafter, supplement the electrolyte every 15 min, and the supplement amount is 25% of the volume of the original electrolyte.

[0097] Example 4:

[0098] The method for simply and rapidly preparing a highly corrosion-resistant carbon-based coating on the metal surface in this example is carried out according to the following steps:

[0099] I. Pretreat the metal sample by grinding, polishing, and cleaning;

[0100] When cleaning the metal sample, wash it successively with deionized water, acetone, and alcohol, and finally dry it;

[0101] The material of the metal sample is stainless steel;

[0102] The shape of the metal sample is a disc;

[0103] II. Prepare an electrolyte containing a carbon source and a conductive salt, and fill the electrolyte into the reaction vessel of the deposition system;

[0104] The carbon source in the electrolyte is acetonitrile, and the mass fraction of the carbon source in the electrolyte is 40%;

[0105] The conductive salt in the electrolyte is NaCl; the mass fraction of the conductive salt in the electrolyte is 0.35%;

[0106] III. Install the pretreated metal sample in Step 1 and the anode electrode in the reaction vessel of the deposition system. The metal sample and the anode electrode are immersed in the electrolyte solution.

[0107] The anode electrode is a graphite plate.

[0108] The distance between the metal sample and the anode electrode is 11 mm.

[0109] IV. Connect the metal sample to the cathode of the power supply and the anode electrode to the anode of the power supply. Turn on the circulating cooling device and the electrolyte stirring device in the deposition system, start the DC power supply to deposit the carbon-based coating, apply a voltage of 260 V, and maintain for 60 min to obtain a carbon-based coating with an average thickness of 2.0 μm. During the deposition of the carbon-based coating, when the reaction proceeds for 15 min, supplement the electrolyte, and the supplement amount is 25% of the volume of the original electrolyte; then supplement the electrolyte every 15 min, and the supplement amount is 25% of the volume of the original electrolyte.

[0110] Example 5:

[0111] The method for simply and rapidly preparing a highly corrosion-resistant carbon-based coating on the metal surface in this example is carried out according to the following steps:

[0112] I. Pretreat the metal sample by grinding, polishing, and cleaning.

[0113] When cleaning the metal sample, wash it successively with deionized water, acetone, and alcohol, and finally dry it.

[0114] The material of the metal sample is carbon steel stainless steel.

[0115] The shape of the metal sample is a disc.

[0116] II. Prepare an electrolyte solution containing a carbon source and a conductive salt, and fill the electrolyte solution into the reaction vessel of the deposition system.

[0117] The carbon source in the electrolyte solution is acetonitrile, and the mass fraction of the carbon source in the electrolyte solution is 30%.

[0118] The conductive salt in the electrolyte solution is NaCl; the mass fraction of the conductive salt in the electrolyte solution is 0.35%.

[0119] III. Install the pretreated metal sample in Step 1 and the anode electrode in the reaction vessel of the deposition system. The metal sample and the anode electrode are immersed in the electrolyte solution.

[0120] The anode electrode is a graphite plate.

[0121] The distance between the metal sample and the anode electrode is 11 mm.

[0122] IV. Connect the metal sample to the cathode of the power supply, connect the anode electrode to the anode of the power supply, turn on the circulating cooling device and the electrolyte stirring device in the deposition system, start the DC power supply for the deposition of the carbon-based coating, apply a voltage of 260 V, and maintain it for 40 min to obtain a carbon-based coating with an average thickness of 2.0 μm; during the deposition of the carbon-based coating, when the reaction proceeds for 15 min, supplement the electrolyte, and the supplement amount is 25% of the volume of the original electrolyte; thereafter, supplement the electrolyte every 15 min, and the supplement amount is 25% of the volume of the original electrolyte.

[0123] Example 6:

[0124] The method for simply and rapidly preparing a highly corrosion-resistant carbon-based coating on the metal surface in this example is carried out according to the following steps:

[0125] I. Pre-treat the metal sample by polishing, buffing and cleaning;

[0126] When cleaning the metal sample, it is successively cleaned with deionized water, acetone and alcohol, and finally dried;

[0127] The material of the metal sample is carbon steel stainless steel;

[0128] The shape of the metal sample is a disc;

[0129] II. Prepare an electrolyte containing a carbon source and a conductive salt, and fill the electrolyte into the reaction vessel of the deposition system;

[0130] The carbon source in the electrolyte is acetonitrile, and the mass fraction of the carbon source in the electrolyte is 30%;

[0131] The conductive salt in the electrolyte is NaCl; the mass fraction of the conductive salt in the electrolyte is 0.35%;

[0132] III. Install the pre-treated metal sample and the anode electrode in the reaction vessel of the deposition system, and immerse the metal sample and the anode electrode in the electrolyte;

[0133] The anode electrode is a graphite plate;

[0134] The distance between the metal sample and the anode electrode is 11 mm;

[0135] IV. Connect the metal sample to the cathode of the power supply, connect the anode electrode to the anode of the power supply, turn on the circulating cooling device and the electrolyte stirring device in the deposition system, start the DC power supply for the deposition of the carbon-based coating, apply a voltage of 260 V, and maintain it for 80 min to obtain a carbon-based coating with an average thickness of 2.2 μm; during the deposition of the carbon-based coating, when the reaction proceeds for 15 min, supplement the electrolyte, and the supplement amount is 25% of the volume of the original electrolyte; thereafter, supplement the electrolyte every 15 min, and the supplement amount is 25% of the volume of the original electrolyte.

Claims

1. A method for simply and quickly preparing a highly corrosion-resistant carbon-based coating on a metal surface, characterized in that: The method for simply and quickly preparing a highly corrosion-resistant carbon-based coating on a metal surface is carried out in the following steps:

1. Pre-treat the metal samples by grinding, polishing and cleaning; The metal sample is cleaned by using deionized water, acetone and alcohol in sequence, and finally dried; 2. preparing an electrolyte containing a carbon source and a conductive salt, and filling the electrolyte into a reaction vessel of the deposition system; The carbon source in the electrolyte is acetonitrile, and the mass fraction of the carbon source in the electrolyte is 20%-40%; The conductive salt in the electrolyte is KCl or NaCl; The mass fraction of the conductive salt in the electrolyte is 0.3%-0.4%; 3. Installing the metal sample and the anode electrode pretreated in step 1 into a reaction vessel of the deposition system, and immersing the metal sample and the anode electrode in the electrolyte; 4. Connect the metal sample to the cathode of the power supply, connect the anode electrode to the anode of the power supply, turn on the circulating cooling device and the electrolyte stirring device in the deposition system, start the DC power supply to deposit the carbon-based coating, apply a voltage of 200-300V, and maintain for 40-80min to obtain a carbon-based coating with a thickness of 2-5μm; during the deposition of the carbon-based coating, replenish the electrolyte when the reaction is carried out for 10-15min, and the replenishment amount is 20%-25% of the original electrolyte volume; thereafter, replenish the electrolyte every 10-15min, and the replenishment amount is 20%-25% of the original electrolyte volume.

2. The method for simply and quickly preparing a highly corrosion-resistant carbon-based coating on a metal surface according to claim 1, characterized in that: The metal sample in step 1 is made of carbon steel, stainless steel, titanium alloy or aluminum alloy.

3. The method for simply and quickly preparing a highly corrosion-resistant carbon-based coating on a metal surface according to claim 1, characterized in that: In step 1, the metal sample is in the shape of a disc, a cuboid or a cylinder.

4. The method for simply and quickly preparing a highly corrosion-resistant carbon-based coating on a metal surface according to claim 1, characterized in that: In step 2, the carbon source in the electrolyte is acetonitrile, and the mass fraction of the carbon source in the electrolyte is 30%.

5. The method for simply and quickly preparing a highly corrosion-resistant carbon-based coating on a metal surface according to claim 1, characterized in that: The mass fraction of the conductive salt in the electrolyte in step 2 is 0.35%.

6. The method for simply and quickly preparing a highly corrosion-resistant carbon-based coating on a metal surface according to claim 1, characterized in that: In step 3, the anode electrode is a graphite plate or a Pt metal sheet.

7. The method for simply and quickly preparing a highly corrosion-resistant carbon-based coating on a metal surface according to claim 1, characterized in that: In step 3, the distance between the metal sample and the anode electrode is 10-12 mm.

8. The method for simply and quickly preparing a highly corrosion-resistant carbon-based coating on a metal surface according to claim 1, characterized in that: Step 4: Connect the metal sample to the cathode of the power supply, connect the anode electrode to the anode of the power supply, turn on the circulating cooling device and the electrolyte stirring device in the deposition system, start the DC power supply to deposit the carbon-based coating, apply a voltage of 260V, and maintain it for 60 minutes to obtain a carbon-based coating with an average thickness of 2.3μm; during the deposition of the carbon-based coating, replenish the electrolyte after 15 minutes of reaction, and the replenishment amount is 25% of the original electrolyte volume; thereafter, replenish the electrolyte every 15 minutes, and the replenishment amount is 25% of the original electrolyte volume.

9. The method for simply and quickly preparing a highly corrosion-resistant carbon-based coating on a metal surface according to claim 1, characterized in that: Step 4: Connect the metal sample to the cathode of the power supply, connect the anode electrode to the anode of the power supply, turn on the circulating cooling device and the electrolyte stirring device in the deposition system, start the DC power supply to deposit the carbon-based coating, apply a voltage of 240V, and maintain for 60 minutes to obtain a carbon-based coating with an average thickness of 2.1μm; During the deposition of the carbon-based coating, the electrolyte was replenished after 15 minutes of reaction, and the replenishment amount was 25% of the original electrolyte volume; thereafter, the electrolyte was replenished every 15 minutes, and the replenishment amount was 25% of the original electrolyte volume.

10. The method for simply and quickly preparing a highly corrosion-resistant carbon-based coating on a metal surface according to claim 1, characterized in that: Step 4: Connect the metal sample to the cathode of the power supply, connect the anode electrode to the anode of the power supply, turn on the circulating cooling device and the electrolyte stirring device in the deposition system, start the DC power supply to deposit the carbon-based coating, apply a voltage of 260V, and maintain for 60 minutes to obtain a carbon-based coating with an average thickness of 2.2μm; during the deposition of the carbon-based coating, replenish the electrolyte after 15 minutes of reaction, and the replenishment amount is 25% of the original electrolyte volume; thereafter, replenish the electrolyte every 15 minutes, and the replenishment amount is 25% of the original electrolyte volume.

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