Electroplating solution catalyzed by dissimilar metal ions as well as preparation method and application of electroplating solution

Abstract

The invention belongs to the technical field of electroplating, and discloses a dissimilar metal ion catalyzed electroplating solution as well as a preparation method and application thereof, and the electroplating solution comprises the following components by molar concentration: 0.02-0.25 mol / L of oxalic acid, 0.008-0.04 mol / L of citric acid and 0.04-0.1 mol / L of aluminum salt; the preparation method of the electroplating solution comprises the following steps: dissolving oxalic acid and citric acid in water to obtain a basic solution A; and aluminum salt is dissolved in the basic solution A, and the electroplating solution is obtained. The electroplating liquid does not have a replacement reaction with a to-be-plated part in the electroplating process of steel copper plating, so that the adhesion performance of a copper plating layer and the to-be-plated part of a steel product is improved; and the service life of the electroplating liquid is more than 10 times that of a common electroplating liquid, electrolyte such as main salt does not need to be supplemented, repeated use and subsequent treatment are facilitated, and the post-treatment cost of the electroplating liquid is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of electroplating, and in particular relates to an electroplating solution catalyzed by heterogeneous metal ions and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not be necessarily regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Oil pipe couplings are devices used to connect and fix oil pipes. They are mainly made of carbon steel and alloy steel. They are widely used in oil and gas exploration, mining, transportation and other fields, and play an important role in connecting oil pipes and maintaining pipeline stability and integrity. With the growth of the world's population and the acceleration of industrialization, the global demand for oil and gas continues to grow, which directly drives the demand for oil and gas extraction equipment such as oil pipe couplings. As one of the world's largest energy consumers, China has a huge demand for oil and gas, which directly drives the demand for oil and gas extraction equipment such as oil pipe couplings. With the development of domestic oil and gas fields, especially the development of unconventional oil and gas resources such as deep-sea oil and gas and shale gas, the performance and quality requirements for oil pipe couplings are getting higher and higher.

[0004] In order to extend the service life of oil well pipes and reduce costs, oil fields usually require oil pipes to be used multiple times. This places strict requirements on the corrosion resistance and galling resistance of the couplings. Once the oil pipe couplings have serious corrosion or galling problems, the integrity of the threaded connection will be damaged. Continued use may cause leakage at the connection, weakened connection strength, and even serious accidents such as falling off the well, causing significant economic losses to the oil field. Therefore, it is very important to research and develop to improve the corrosion resistance and galling resistance of the couplings.

[0005] Copper plating on the surface of the coupling can effectively improve the corrosion resistance and anti-seizing performance of the coupling. The common copper plating process currently uses strong acid and copper salt as the main components of the electroplating solution. However, when electroplating on the surface of carbon steel, a replacement reaction is likely to occur in advance. The copper plating layer generated on the carbon steel surface has poor bonding strength, and the presence of the replacement layer affects the adhesion of the subsequent electroplating layer. Even if the circuit is connected and then placed in the plating solution, a replacement reaction will still occur when it is first placed in the electroplating solution, resulting in insufficient bonding strength of the subsequent plating layer.

[0006] When the traditional electroplating solution is used to electroplate the workpiece, the concentration of conductive ions in the electroplating solution decreases as the electroplating time progresses. Electrolyte ions need to be added at intervals to maintain the electroplating of the workpiece, and the change in the concentration of conductive ions in the electroplating solution will lead to a decrease in the quality of electroplating. In addition, traditional electroplating solutions often use strong acids, which not only harm the environment, but also cause obvious harm to operators. Summary of the invention

[0007] In order to overcome the deficiencies in the prior art, the purpose of the present invention is to provide a plating solution catalyzed by heterogeneous metal ions, and a preparation method and application thereof. The plating solution of the present invention is used to electroplate copper on steel products. The copper plating layer has good bonding strength with the steel products, thereby improving the corrosion resistance and galling resistance of the metal plated parts.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] The first aspect of the present invention provides a heterogeneous metal ion catalyzed electroplating solution, which comprises the following components in molar concentrations: 0.02-0.25 mol / L oxalic acid, 0.008-0.04 mol / L citric acid and 0.04-0.1 mol / L aluminum salt.

[0010] The second aspect of the present invention provides a method for preparing a heterogeneous metal ion-catalyzed electroplating solution, comprising:

[0011] Dissolve oxalic acid and citric acid in water to obtain basic solution A;

[0012] Aluminum salt is dissolved in base solution A to obtain an electroplating solution.

[0013] The third aspect of the present invention provides an electroplating method, comprising: using the above-mentioned electroplating solution, taking the steel product to be plated as the cathode, taking metal copper as the anode, and applying direct current to electroplate the steel product to be plated.

[0014] In the process of copper plating on steel oil pipe couplings, the inventors found that when electroplating with traditional electroplating solutions, the bonding strength between the copper plating layer and the steel product to be plated is poor, and the performance of the plated parts after electroplating is poor. When electroplating oil pipe couplings, the electroplated oil pipe couplings are prone to corrosion or sticking caused by the shedding of the coating during use, which damages the integrity of the thread and causes oil leakage or even accidents such as falling off the well.

[0015] The main salt metal ion Cu is directly added to the traditional electroplating solution. 2+ As the plating cation, thus completing the electroplating. However, in the early stage of electroplating, the main salt ion Cu 2+, will directly undergo a replacement reaction with the plated parts of the steel products, affecting the uniformity, adhesion and porosity of the coating, and affecting the performance of the coating. The existing technology often pre-nickel-plated the steel products before copper plating to reduce the deposition overpotential of the coating, so as to enhance the adhesion between the copper layer and the substrate.

[0016] The present invention creatively omits the main salt cation Cu 2+ , only aluminum salt and weak acid are added to the plating solution, especially aluminum salt, as conductive ions to improve the conductivity of the plating solution. After power is turned on, electroplating will be carried out. Since there is no Cu in the plating solution 2+ Therefore, there will be no replacement reaction with the plated parts, and the adhesion performance of the coating will not be affected. At the same time, the synergistic effect of amphoteric metal ions, aluminum ions, aluminum salt anions and ionized weak acids, on the one hand, constitute conductive ions, and on the other hand, with the consumption of electrolytes, they can maintain the conductivity and pH of the plating solution, and maintain a stable electric field and current in the plating solution.

[0017] The beneficial effects of the present invention are:

[0018] 1. The electroplating solution of the present invention creatively omits the main salt cation Cu 2+ , only aluminum salt and weak acid are added to the plating solution to act as conductive ions after ionization to improve the conductivity of the plating solution. After power is turned on, electroplating will be carried out. Since there is no Cu in the plating solution 2+ Therefore, no replacement reaction will occur with the workpiece to be plated during the electroplating process, which improves the adhesion performance of the copper coating on the steel workpiece to be plated.

[0019] 2. When the electroplating solution is used for electroplating, trivalent aluminum ions, oxalic acid and citric acid work synergistically through ionization and hydrolysis, and have the functions of conductive ions, buffers and pH regulators. They can stabilize the conductivity and pH of the electroplating solution during the electroplating process, prevent the polarization of the electroplating solution, improve the uniformity and adhesion of the copper coating, improve its porosity, and improve the performance of the coating.

[0020] 3. The electroplating solution of the present invention can ensure that the electric field around the plated part is evenly distributed, so that the plated part is bright, burr-free, and free of "burning" phenomenon.

[0021] 4. The electroplating solution of the present invention has a simple composition, and is composed of aluminum salt and weak acid. It can be used continuously for a long time, and its service life is more than 10 times that of ordinary electroplating solutions. It does not need to add electrolytes such as main salts, which is convenient for repeated use and subsequent treatment, reducing the cost of post-treatment of the electroplating solution.

[0022] 5. The electroplating solution of the present invention adopts weak acidic media such as oxalic acid and citric acid which are easy to transport and store. Such acids are weak in acidity and have little harm to human body and environment, and can play a good buffering role to maintain the conductivity and pH of the electroplating solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0024] Figure 1 The macroscopic pictures of carbon steel plate-shaped parts; (a) is carbon steel without copper plating, and (b) is carbon steel after copper plating in Example 1;

[0025] Figure 2 X-ray diffraction patterns of copper coatings on carbon steel surfaces of different embodiments;

[0026] Figure 3 : are SEM morphology images of copper plating layers; wherein (a) is the copper plating layer of Example 4; (b) is the copper plating layer of Example 3;

[0027] Figure 4 The composition distribution diagram and element content results of the coating obtained in Example 6; wherein (a) is the composition distribution diagram of the coating in the scanned area; (b) is the Cu element distribution diagram; (c) is the Fe element distribution diagram; (d) is the C element distribution diagram; (e) is the element spectrum diagram;

[0028] Figure 5 The cross sections of the coatings at different electroplating voltages in the embodiment; wherein (a) is the cross section of the coating at 10V; (b) is the cross section of the coating at 15V; (c) is the cross section of the coating at 20V; (d) is the cross section of the coating at 25V;

[0029] Figure 6 is the contact angle of the copper coating under different electroplating parameters in the embodiment;

[0030] Figure 7 Graph showing the microhardness values ​​of the copper coating at different voltages in the example. DETAILED DESCRIPTION

[0031] In view of the problems that, during the copper plating of existing steel products, the copper layer and the test piece are prone to replacement reaction and the service life of the electroplating solution is short, the present invention proposes an electroplating solution catalyzed by heterogeneous metal ions and a preparation method and application thereof.

[0032] The first aspect of the present invention provides a heterogeneous metal ion catalyzed electroplating solution, which comprises the following components in molar concentrations: 0.02-0.25 mol / L oxalic acid, 0.008-0.04 mol / L citric acid and 0.04-0.1 mol / L aluminum salt.

[0033] In some embodiments, the aluminum salt is aluminum nitrate, aluminum chloride, or aluminum sulfate.

[0034] In some embodiments, a leveling agent is further included, wherein the leveling agent is one or more of sodium dodecylbenzene sulfonate, alkyl dimethyl ammonium chloride, and 4-aminosalicylic acid;

[0035] In some embodiments, the leveling agent is sodium dodecylbenzene sulfonate. More preferably, the concentration of sodium dodecylbenzene sulfonate in the electroplating solution is 0.5 g / L to 5 g / L.

[0036] In some embodiments, a brightener is further included, and the brightener is any one of sodium polydihexadimethoxypropane sulfonate, sodium 3-mercaptopropane sulfonate, sodium N,N-dimethyldithiocarbonylpropane sulfonate, isothioureapropanesulfonic acid inner salt or sodium 3-(benzothiazole-2-mercapto)-propane sulfonate, or a combination of at least two thereof.

[0037] In some embodiments, the brightener is preferably sodium 3-mercaptopropane sulfonate, and the concentration of sodium 3-mercaptopropane sulfonate in the electroplating solution is 1 g / L to 2.5 g / L.

[0038] The second aspect of the present invention provides a method for preparing a heterogeneous metal ion-catalyzed electroplating solution, comprising:

[0039] Dissolve oxalic acid and citric acid in water to obtain basic solution A;

[0040] Aluminum salt is dissolved in base solution A to obtain an electroplating solution.

[0041] In some embodiments, aluminum salt and leveling agent are dissolved in base solution A in sequence to obtain an electroplating solution.

[0042] In some embodiments, aluminum salt, leveling agent, and brightener are sequentially dissolved in base solution A, and stirred evenly to obtain an electroplating solution.

[0043] In some embodiments, the water is distilled water, deionized water or pure water.

[0044] The third aspect of the present invention provides an electroplating method, comprising: using the above-mentioned electroplating solution, taking the steel product to be plated as the cathode, taking metal copper as the anode, and applying direct current to electroplate the steel product to be plated.

[0045] In some embodiments, the electroplating voltage is 5V-25V, the electroplating time is 20min-80min, and the electroplating temperature is 28°C-50°C.

[0046] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0047] Example 1

[0048] This embodiment provides a plating solution catalyzed by heterogeneous metal ions, and the preparation method thereof is as follows:

[0049] (1) Dissolve 10 g (0.111 mol / l) oxalic acid and 2.5 g (0.013 mol / l) citric acid in 240 mL of distilled water at room temperature and stir to obtain an acidic solution (i.e., base solution A);

[0050] (2) Add 22 g of aluminum nitrate (0.103 mol / l) to the above acidic solution and stir evenly to obtain base solution B;

[0051] (3) Add 1.2 g (0.003 mol / l) of leveling agent sodium dodecylbenzene sulfonate and 1.5 g (0.0084 mol / l) of brightener sodium 3-mercaptopropane sulfonate to the solution obtained in the above step (2), and stir evenly to obtain an electroplating solution.

[0052] This embodiment also provides an electroplating layer, which is obtained by electroplating a carbon steel plate-shaped part as a to-be-plated part using direct current. The specific electroplating method is as follows:

[0053] The temperature of the electroplating solution was heated to 30° C., and after the temperature was stabilized, the stainless steel plate was used as the cathode, the copper sheet was used as the anode, and the electroplating voltage was set to 10 V for 40 minutes to obtain an electroplated part.

[0054] Example 2

[0055] This embodiment provides a plating solution catalyzed by heterogeneous metal ions, and the preparation method thereof is as follows:

[0056] (1) Dissolve 9 g of oxalic acid and 3.5 g of citric acid in 240 mL of distilled water and stir to obtain an acidic solution (i.e., base solution A);

[0057] (2) Add 24 g of aluminum nitrate to the above acidic solution and stir evenly to obtain base solution B;

[0058] (3) Add 1.2 g (0.003 mol / l) of sodium dodecylbenzene sulfonate as a leveling agent and 1.5 g (0.0084 mol / l) of sodium 3-mercaptopropane sulfonate as a brightener to the solution obtained in step (2) above, and stir evenly to obtain an electroplating solution.

[0059] This embodiment also provides an electroplating layer, which is obtained by electroplating a carbon steel plate-shaped part as a to-be-plated part using direct current. The specific electroplating method is as follows:

[0060] The temperature of the electroplating solution was heated to 40° C., and after the temperature was stabilized, the stainless steel plate was used as the cathode, the copper sheet was used as the anode, and the electroplating voltage was set to 15 V for 40 minutes to obtain an electroplated part.

[0061] Example 3

[0062] This embodiment provides a plating solution catalyzed by heterogeneous metal ions, and the preparation method thereof is as follows:

[0063] (1) Dissolve 1.8 g of oxalic acid and 6 g of citric acid in 240 mL of distilled water and stir to obtain an acidic solution (i.e., base solution A);

[0064] (2) Add 20.5 g of aluminum nitrate to the above acidic solution and stir evenly to obtain base solution B;

[0065] (3) Add 0.5 g of sodium dodecylbenzene sulfonate as a leveling agent and 1.5 g of sodium 3-mercaptopropane sulfonate as a brightener to the solution obtained in step (2) above, and stir evenly to obtain an electroplating solution.

[0066] This embodiment also provides an electroplating layer, which is obtained by electroplating a carbon steel plate-shaped part as a to-be-plated part using direct current. The specific electroplating method is as follows:

[0067] The temperature of the electroplating solution was heated to 28° C., and after the temperature was stabilized, the stainless steel plate was used as the cathode, the copper sheet was used as the anode, and the electroplating voltage was set to 25 V for 20 minutes to obtain an electroplated part.

[0068] Example 4

[0069] This embodiment provides a plating solution catalyzed by heterogeneous metal ions, and the preparation method thereof is as follows:

[0070] (1) Dissolve 2.2 g of oxalic acid and 5 g of citric acid in 240 mL of distilled water and stir to obtain an acidic solution (i.e., base solution A);

[0071] (2) Add 24.5 g of aluminum sulfate to the above acidic solution and stir evenly to obtain base solution B;

[0072] (3) Add 2 g of sodium dodecylbenzene sulfonate as a leveling agent and 0.1 g of sodium 3-mercaptopropane sulfonate as a brightener to the solution obtained in step (2) above, and stir evenly to obtain an electroplating solution.

[0073] This embodiment also provides an electroplating layer, which is obtained by electroplating a carbon steel plate-shaped part as a to-be-plated part using direct current. The specific electroplating method is as follows:

[0074] The temperature of the electroplating solution was heated to 35° C., and after the temperature was stabilized, the stainless steel plate was used as the cathode, the copper sheet was used as the anode, and the electroplating voltage was set to 20 V for 30 minutes to obtain an electroplated part.

[0075] Example 5

[0076] This embodiment provides a plating solution catalyzed by heterogeneous metal ions, and the preparation method thereof is as follows:

[0077] (1) Dissolve 4.3 g of oxalic acid and 4.2 g of citric acid in 240 mL of distilled water and stir to obtain an acidic solution (i.e., base solution A);

[0078] (2) Add 16.5 g of aluminum sulfate to the above acidic solution and stir evenly to obtain base solution B;

[0079] (3) Add 2 g of sodium dodecylbenzene sulfonate as a leveling agent and 1 g of sodium 3-mercaptopropane sulfonate as a brightener to the solution obtained in step (2) above, and stir evenly to obtain an electroplating solution.

[0080] This embodiment also provides an electroplating layer, which is obtained by electroplating a carbon steel plate-shaped part as a to-be-plated part using direct current. The specific electroplating method is as follows:

[0081] The temperature of the electroplating solution was heated to 35° C., and after the temperature was stabilized, the stainless steel plate was used as the cathode, the copper sheet was used as the anode, and the electroplating voltage was set to 20 V for 40 minutes to obtain an electroplated part.

[0082] Example 6

[0083] This embodiment provides a plating solution catalyzed by heterogeneous metal ions, and the preparation method thereof is as follows:

[0084] (1) Dissolve 5.4 g of oxalic acid and 3.2 g of citric acid in 240 mL of distilled water and stir to obtain an acidic solution (i.e., base solution A);

[0085] (2) Add 15.3 g of aluminum sulfate to the above acidic solution and stir evenly to obtain base solution B;

[0086] (3) Add 2 g of sodium dodecylbenzene sulfonate as a leveling agent and 0.5 g of sodium 3-mercaptopropane sulfonate as a brightener to the solution obtained in step (2) above, and stir evenly to obtain an electroplating solution.

[0087] This embodiment also provides an electroplating layer, which is obtained by electroplating a carbon steel plate-shaped part as a to-be-plated part using direct current. The specific electroplating method is as follows:

[0088] The temperature of the electroplating solution was heated to 40° C., and after the temperature was stabilized, the stainless steel plate was used as the cathode, the copper sheet was used as the anode, and the electroplating voltage was set to 15 V for 40 minutes to obtain an electroplated part.

[0089] Example 7

[0090] This embodiment provides a plating solution catalyzed by heterogeneous metal ions, and the preparation method thereof is as follows:

[0091] (1) Dissolve 20 g of oxalic acid and 6 g of citric acid in 240 mL of distilled water and stir to obtain an acidic solution (i.e., base solution A);

[0092] (2) Add 34.2 g of aluminum sulfate to the above acidic solution and stir evenly to obtain base solution B;

[0093] (3) Add 2 g of sodium dodecylbenzene sulfonate as a leveling agent and 0.5 g of sodium 3-mercaptopropane sulfonate as a brightener to the solution obtained in step (2) above, and stir evenly to obtain an electroplating solution.

[0094] This embodiment also provides an electroplating layer, which is obtained by electroplating a carbon steel plate-shaped part as a to-be-plated part using direct current. The specific electroplating method is as follows:

[0095] The temperature of the electroplating solution was heated to 25° C., and after the temperature was stabilized, the stainless steel plate was used as the cathode, the copper sheet was used as the anode, and the electroplating voltage was set to 10 V for 60 minutes to obtain an electroplated part.

[0096] Example 8

[0097] This embodiment provides a plating solution catalyzed by heterogeneous metal ions, and the preparation method thereof is as follows:

[0098] (1) 8.6 g of oxalic acid and 1.4 g of citric acid were dissolved in 240 mL of distilled water and stirred to obtain an acidic solution (i.e., base solution A);

[0099] (2) Add 10 g of aluminum sulfate to the above acidic solution and stir evenly to obtain base solution B;

[0100] (3) Add 5 g of sodium dodecylbenzene sulfonate as a leveling agent and 0.5 g of sodium 3-mercaptopropane sulfonate as a brightener to the solution obtained in step (2) above, and stir evenly to obtain an electroplating solution.

[0101] This embodiment also provides an electroplating layer, which is obtained by electroplating a carbon steel plate-shaped part as a to-be-plated part using direct current. The specific electroplating method is as follows:

[0102] The temperature of the electroplating solution was heated to 45° C., and after the temperature was stabilized, the stainless steel plate was used as the cathode, the copper sheet was used as the anode, and the electroplating voltage was set to 10 V for 70 minutes to obtain an electroplated part.

[0103] Example 9

[0104] This embodiment provides a plating solution catalyzed by heterogeneous metal ions, and the preparation method thereof is as follows:

[0105] (1) Dissolve 9.7 g of oxalic acid and 0.96 g of citric acid in 240 mL of distilled water and stir to obtain an acidic solution (i.e., base solution A);

[0106] (2) Add 2 g of aluminum sulfate to the above acidic solution and stir evenly to obtain base solution B;

[0107] (3) Add 5 g of sodium dodecylbenzene sulfonate as a leveling agent and 1.5 g of sodium 3-mercaptopropane sulfonate as a brightener to the solution obtained in step (2) above, and stir evenly to obtain an electroplating solution.

[0108] This embodiment also provides an electroplating layer, which is obtained by electroplating a carbon steel plate-shaped part as a to-be-plated part using direct current. The specific electroplating method is as follows:

[0109] The temperature of the electroplating solution was heated to 50° C., and after the temperature was stabilized, the stainless steel plate was used as the cathode, the copper sheet was used as the anode, and the electroplating voltage was set to 5 V for 80 minutes to obtain an electroplated part.

[0110] Comparative Example 1

[0111] This comparative example provides an electroplating solution, and its preparation method is as follows:

[0112] (1) Dissolve 40 g of oxalic acid and 20 g of citric acid in 240 mL of distilled water and stir to obtain an acidic solution (i.e., base solution A);

[0113] (2) Add 150 g of aluminum nitrate to the above acidic solution and stir evenly to obtain base solution B;

[0114] (3) Add 2 g of sodium dodecylbenzene sulfonate as a leveling agent and 1 g of sodium 3-mercaptopropane sulfonate as a brightener to the solution obtained in step (2) above, and stir evenly to obtain an electroplating solution.

[0115] This comparative example also provides an electroplating layer, which is obtained by electroplating a carbon steel plate-shaped part as a to-be-plated part using direct current. The specific electroplating method is as follows:

[0116] The temperature of the electroplating solution was heated to 40° C., and after the temperature was stabilized, the stainless steel plate was used as the cathode, the copper sheet was used as the anode, and the electroplating voltage was set to 15 V for 40 minutes to obtain an electroplated part.

[0117] Comparative Example 2

[0118] This comparative example provides a heterogeneous metal ion catalyzed (1) 0.4 g of oxalic acid is dissolved in 240 mL of distilled water and stirred to obtain an acidic solution (i.e., base solution A);

[0119] (3) Add 2 g of sodium dodecylbenzene sulfonate as a leveling agent and 1 g of sodium 3-mercaptopropane sulfonate as a brightener to the solution obtained in step (2) above, and stir evenly to obtain an electroplating solution.

[0120] This comparative example also provides an electroplating layer, which is obtained by electroplating a carbon steel plate-shaped part as a to-be-plated part using direct current. The specific electroplating method is as follows:

[0121] The temperature of the electroplating solution was heated to 40° C., and after the temperature was stabilized, the stainless steel plate was used as the cathode, the copper sheet was used as the anode, and the electroplating voltage was set to 15 V for 40 minutes to obtain an electroplated part.

[0122] Comparative Example 3

[0123] This comparative example provides an electroplating solution, and its preparation method is as follows:

[0124] (1) Dissolve 9 g of oxalic acid and 3.5 g of citric acid in 240 mL of distilled water and stir to obtain an acidic solution (i.e., base solution A);

[0125] (2) Add 24 g of aluminum nitrate to the above acidic solution and stir evenly to obtain base solution B;

[0126] (3) Add 1.2 g of sodium dodecylbenzene sulfonate as a leveling agent and 0.9 g of sodium 3-mercaptopropane sulfonate as a brightener to the solution obtained in step (2) above, and stir evenly to obtain an electroplating solution.

[0127] This comparative example also provides an electroplating layer, which is obtained by electroplating a carbon steel plate-shaped part as a to-be-plated part using direct current. The specific electroplating method is as follows:

[0128] The temperature of the electroplating solution was heated to 40° C., and after the temperature was stabilized, the stainless steel plate was used as the cathode, the copper sheet was used as the anode, and the electroplating voltage was set to 40 V for 40 minutes to obtain an electroplated part.

[0129] Comparative Example 4

[0130] This comparative example provides an electroplating solution, and its preparation method is as follows:

[0131] (1) Dissolve 9 g of oxalic acid and 3.5 g of citric acid in 240 mL of distilled water and stir to obtain an acidic solution (i.e., base solution A);

[0132] (2) Add 24 g of aluminum nitrate to the above acidic solution and stir evenly to obtain base solution B;

[0133] (3) Add 1.2 g of sodium dodecylbenzene sulfonate as a leveling agent and 0.9 g of sodium 3-mercaptopropane sulfonate as a brightener to the solution obtained in step (2) above, and stir evenly to obtain an electroplating solution.

[0134] This comparative example also provides an electroplating layer, which is obtained by electroplating a carbon steel plate-shaped part as a to-be-plated part using direct current. The specific electroplating method is as follows:

[0135] The temperature of the electroplating solution was heated to 80° C., and after the temperature was stabilized, the stainless steel plate was used as the cathode, the copper sheet was used as the anode, and the electroplating voltage was set to 40 V for 40 minutes to obtain an electroplated part.

[0136] Comparative Example 5

[0137] This comparative example provides an electroplating solution, and its preparation method is as follows:

[0138] (1) Weigh 50 g of copper sulfate, dissolve it in 200 ml of water, add 12.5 ml of ammonia water, and stir well.

[0139] (2) Add 7.5 g NH4Cl and stir evenly.

[0140] (3) Add 7.5 g H3BO3, stir evenly after dissolving, then add 0.125 g sodium dodecylbenzene sulfonate, stir evenly after dissolving.

[0141] (4) The volume is adjusted to 500 ml to obtain an electroplating solution.

[0142] (5) The electroplating parameters are current density 3A / dm 2 , pH is 4, time is 15min, temperature is 40℃.

[0143] This comparative example also provides an electroplating layer, which is obtained by electroplating a carbon steel plate-shaped part as a to-be-plated part using direct current. The specific electroplating method is as follows:

[0144] The temperature of the electroplating solution was heated to 40° C., and after the temperature was stabilized, the stainless steel plate was used as the cathode, the copper sheet was used as the anode, and the electroplating voltage was set to 40 V for 40 minutes to obtain an electroplated part.

[0145] Performance Testing

[0146] The electroplated parts of Examples 1-9 and Comparative Examples 1-4 were observed and tested for performance:

[0147] 1. Coating bonding ability: The bending method is used to test the bonding ability of the coating. The electroplated part is repeatedly bent along an axis with a diameter equal to the thickness of the plated part until the plated part breaks, and check whether the coating is peeling or falling off. If the coating does not peel or fall off, the bonding strength is strong; if it peels or falls off, the bonding strength is weak.

[0148] 2. Coating uniformity: Check the coating with naked eyes and microscope to see if there is color difference, whether the covering degree is complete, and measure the thickness of the coating. When the average coating thickness is less than 20μm, the thickness fluctuation is less than 3μm, which is uniform, and greater than or equal to 3μm, which is uneven; when the coating thickness is greater than 20μm, the thickness fluctuation is less than 8μm, which is uniform, and greater than or equal to 8μm, which is uneven.

[0149] 3. Corrosion resistance: Carry out salt spray corrosion test according to the national standard GBT10125-2021 to test the corrosion resistance of the coating. The corrosion resistance level is evaluated as follows:

[0150] First level: After the salt spray test, there is no obvious corrosion phenomenon, the coating remains in good condition, and there is no rust or fall off, which can be rated as level I.

[0151] Level II: In the salt spray test, there are slight signs of corrosion, but no serious corrosion occurs. The overall performance of the coating can still be maintained and can still meet the basic requirements in actual use. It can be rated as Level II.

[0152] Level III: During the salt spray test, obvious corrosion occurs, the coating rusts or partially falls off, but the overall structure is not seriously affected and can still maintain its proper functions to a certain extent. It can be rated as Level III.

[0153] Level 4: In the salt spray test, the coating exhibits severe corrosion, with large areas of rust, peeling or damage, which seriously affects the performance and appearance of the coating and requires repair or replacement. It can be rated as the lowest level IV.

[0154] 4. Appearance of plated parts: Observe whether the plated parts have burrs or sponge phenomena.

[0155] Table 1 Performance of electroplated parts under different conditions

[0156]

[0157] The plated parts obtained in the embodiment of the present invention have significantly better coating bonding ability, coating uniformity and corrosion resistance than the comparative examples, and have uniform appearance without burrs, while comparative examples 3, 4 and 5 all have burrs. It can be seen that aluminum salt, oxalic acid and citric acid are used to provide conductive ions in the electroplating solution and buffer and adjust the pH value, making the electroplating process more uniform, reducing the edge effect, and preventing burrs and the like.

[0158] Comparative Example 1 uses high concentration aluminum salt, oxalic acid and citric acid as the electroplating solution for electroplating, and the uniformity and corrosion resistance of the coating are worse than those of the embodiment; when Comparative Example 2 uses only oxalic acid and citric acid as the electroplating medium, the circuit is short-circuited, no path is formed, and the electroplating process cannot be carried out. Comparative Example 5 adds copper salt, and the copper salt and iron undergo a substitution reaction, and a loose copper single substance is generated on the surface of the carbon steel, which is very weakly bonded to the substrate.

[0159] It can be seen from the embodiment and comparative example 2 that in the process of the present invention, since the present application does not add the main salt ions, the metal aluminum salt is required to improve the conductivity of the electroplating solution and provide the conductive anions and cations when the electroplating solution is started. At the same time, the presence of the aluminum salt has the function of adjusting the pH and catalyzing the electrode reaction. The electroplating solution is added with aluminum salt and weak acid medium, and the aluminum salt and weak acid can buffer the pH and anion and cation concentration of the electroplating solution. During the electroplating process, the edge effect is suppressed and no burrs are generated, which proves that the distribution of the electric lines is relatively uniform, and no obvious plating mud is seen on the surface of the copper plate substrate.

[0160] Plating solution service life test

[0161] 400 mL of the plating solution in Example 1 of the present invention and Comparative Example 5 were taken respectively, and the carbon steel plates to be plated of the same shape and size were electroplated. The size of the stainless steel plate was 25*25*2 mm. During the electroplating process, the speed and quality of the electroplating of the electroplating solution of Comparative Example 5 gradually decreased with the increase in the number of electroplated stainless steel plates. When 57 carbon steel plates were electroplated, the speed of electroplating and the quality of the electroplated parts decreased significantly. After adding copper sulfate to the plating solution, the original plating speed and plating quality were restored. The speed and quality of the electroplating of the electroplating solution of Example 1 did not change significantly with the increase in the number of electroplated stainless steel plates. After electroplating 200 carbon steel plates, an appropriate amount of oxalic acid was added, and electroplating could still be continued. The electroplating solution of Example 1 has good repeatability.

[0162] In summary, the preparation method of the electroplating solution of the present invention is simple, and a weak acid is used for electroplating. The acid has weak acidity, is less harmful to the human body and the environment, and can play a good buffering role to maintain the conductivity and pH of the electroplating solution. The electroplating solution has a long life. Since it does not consume metal cations, it can be used continuously in theory, and its electroplating has a good effect. The contact angle of the coating prepared by this method is above 100°, and the electroplated copper coating can be used for anti-adhesion treatment of oil pipe couplings.

[0163] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A plating solution catalyzed by heterogeneous metal ions, characterized in that: According to the molar concentration meter, the components include the following concentrations: oxalic acid 0.02-0.25 mol / L, citric acid 0.008-0.04 mol / L and aluminum salt 0.04-0.1 mol / L.

2. The electroplating solution according to claim 1, characterized in that The aluminum salt is aluminum nitrate, aluminum chloride or aluminum sulfate.

3. The electroplating solution according to claim 1, characterized in that The invention also comprises a leveling agent, which is one or more of sodium dodecylbenzene sulfonate, alkyl dimethyl ammonium chloride and 4-aminosalicylic acid.

4. The electroplating solution according to claim 3, characterized in that The leveling agent is sodium dodecylbenzene sulfonate. More preferably, the concentration of sodium dodecylbenzene sulfonate in the electroplating solution is 0.5 g / L to 5 g / L.

5. The electroplating solution according to claim 1, characterized in that The invention also includes a brightener, which is any one of sodium polydihexadimethoxypropane sulfonate, sodium 3-mercaptopropane sulfonate, sodium N,N-dimethyldithiocarbonylpropane sulfonate, isothioureapropanesulfonic acid inner salt or sodium 3-(benzothiazole-2-mercapto)-propane sulfonate or a combination of at least two thereof.

6. The electroplating solution according to claim 5, characterized in that The brightener is sodium 3-mercaptopropane sulfonate, and the concentration of sodium 3-mercaptopropane sulfonate in the electroplating solution is 1 g / L to 2.5 g / L.

7. The method for preparing the electroplating solution according to any one of claims 1 to 6, characterized in that: include: Dissolve oxalic acid and citric acid in water to obtain basic solution A; Aluminum salt is dissolved in base solution A to obtain an electroplating solution.

8. The preparation method according to claim 7, characterized in that: Aluminum salt and leveling agent are dissolved in base solution A to obtain an electroplating solution; preferably, aluminum salt, leveling agent and brightener are dissolved in base solution A in sequence, and stirred evenly to obtain an electroplating solution.

9. An electroplating method, characterized in that: include: The electroplating solution according to claim 7 is used, the steel product to be plated is used as the cathode, the metal copper is used as the anode, and direct current is passed through the steel product to plate the steel product.

10. The electroplating method according to claim 9, characterized in that: The electroplating voltage is 5V-25V, the electroplating time is 20min-80min, and the electroplating temperature is 25°C-50°C.

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