A nickel-tungsten-phosphorus coating electroplating process

Abstract

The present application relates to the field of electroplating technology, and specifically discloses a nickel tungsten phosphorus coating electroplating process, which includes the following steps: S1, preparing a nano-composite electroplating solution, wherein the composite electroplating solution contains nickel salt, tungstate, hypophosphite, nano silicon carbide powder, ZIF-67@MXene core-shell nanosheets, a composite complexing agent and water; S2, etching the surface of the workpiece to be plated using a plasma mixed gas; S3, electroplating the surface-treated workpiece to be plated under the action of a pulse current and an alternating magnetic field, and ultrasonically stirring the composite electroplating solution during the electroplating process; S4, annealing the workpiece under nitrogen protection. The electroplating process of the present application can effectively improve the composition uniformity and structural density of the nickel tungsten phosphorus coating through the synergistic effect of nano-SiC and ZIF-67@MXene, thereby effectively improving the corrosion resistance of the nickel tungsten phosphorus coating in a complex oil and gas environment.

Description

Technical Field

[0001] The present application relates to the field of electroplating technology, and more specifically, to a nickel-tungsten-phosphorus electroplating process. Background Art

[0002] In the oil industry, electroplating, as a core method for improving the surface performance of oil machinery and accessories, is crucial for ensuring the stable operation of equipment in harsh environments. During oil extraction operations, mechanical equipment is exposed to complex environments characterized by high temperature, high pressure, high salinity, and rich corrosive media such as hydrogen sulfide and carbon dioxide. Furthermore, it must withstand dynamic loads such as mechanical vibration and fluid erosion during drilling. In this context, applying a nickel-based alloy coating to the surface of equipment through electroplating can effectively improve the corrosion resistance, wear resistance, and mechanical properties of the substrate, making it a key technical approach to extending equipment service life and reducing maintenance costs.

[0003] Currently, nickel-tungsten-phosphorus coatings used for corrosion protection of petroleum machinery and equipment are primarily produced through traditional electroplating or chemical plating processes. In traditional electroplating, nickel ions, tungsten ions, and phosphate ions in the plating solution undergo a reduction reaction on the substrate surface under the action of a DC electric field to form a coating. Chemical plating utilizes an oxidation-reduction reaction to autocatalytically deposit metal ions on a catalytic surface in the absence of an applied current. Nickel-tungsten-phosphorus coatings produced using these processes can, to a certain extent, meet the corrosion protection requirements of petroleum machinery and equipment. They possess a relatively dense structure, providing protection in conventional corrosive environments. Furthermore, the preparation process is relatively simple and cost-effective, making them widely used in the petroleum industry.

[0004] However, the existing nickel-tungsten-phosphorus coating and electroplating process still have many defects. On the one hand, the coating prepared by the traditional process is insufficient in composition uniformity, and the distribution of tungsten and phosphorus elements is not uniform enough, resulting in large differences in the local corrosion resistance of the coating. Especially in the complex environment of high temperature, high pressure, high mineralization and corrosive gases such as hydrogen sulfide and carbon dioxide in oil extraction, the coating is prone to local corrosion perforation, which in turn causes corrosion of the substrate. On the other hand, the existing process has limited ability to control the microstructure of the coating, and the porosity of the coating is high, which cannot effectively block the penetration of corrosive media. Therefore, how to improve the composition uniformity and structural density of the nickel-tungsten-phosphorus coating, thereby enhancing its corrosion resistance in complex petroleum environments, is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] In order to improve the corrosion resistance of nickel-tungsten-phosphorus coatings in complex oil and gas environments, the present application provides a nickel-tungsten-phosphorus coating electroplating process.

[0006] The nickel-tungsten-phosphorus coating electroplating process provided in this application adopts the following technical solutions:

[0007] A nickel-tungsten-phosphorus coating electroplating process comprises the following steps:

[0008] S1. Preparing a nanocomposite electroplating solution, wherein the composite electroplating solution comprises nickel salt, tungstate, hypophosphite, nano-silicon carbide powder, ZIF-67@MXene core-shell nanosheets, a composite complexing agent, and water;

[0009] S2, using plasma mixed gas to etch the surface of the workpiece to be plated, the etching pressure is 50-100Pa, and the processing time is 15-20min;

[0010] S3. Controlling the plating solution temperature at 65-70°C, electroplating the surface-treated workpiece under the action of a pulse current and an alternating magnetic field, wherein the pulse current has a frequency of 1-5 kHz, a duty cycle of 20%-40%, an average current density of 3-5 A / dm², an alternating magnetic field strength of 0.5-2 T, and a frequency of 50-200 Hz, and ultrasonically stirring the composite plating solution during the electroplating process;

[0011] S4. Under nitrogen protection, anneal the workpiece.

[0012] By employing the above-mentioned technical solution, etching with a plasma mixed gas increases the effective specific surface area of ​​the workpiece to be plated, thereby improving the bonding strength between the coating and the workpiece. In the aforementioned composite electroplating solution, nickel salts, tungstates, and hypophosphites provide the primary sources of nickel, tungsten, and phosphorus. The coordination effect of the composite complexing agent (glycine + hydroxyethylidene diphosphonic acid) stabilizes the metal ions in the form of complex ions, preventing uneven deposition rates due to concentration fluctuations and thus reducing compositional heterogeneity in the coating. ZIF-67@MXene core-shell nanosheets provide catalytic active sites, promoting the co-deposition of tungsten and phosphorus, thereby improving the compositional uniformity and structural density of the coating. Nano-silicon carbide powder, as a nanoparticle reinforcement phase, refines the grains and fills pores, further enhancing structural density. Nano-SiC and ZIF-67@MXene jointly refine the grains through "particle filling + layer stacking", the composite chelating agent and pulse current synergistically control the ion deposition rate, the pulse current suppresses dendrite growth during the electroplating process, and the alternating magnetic field generates Lorentz force to promote ion migration, further reducing the porosity of the coating, and ultimately forming a "uniform composition and dense structure" coating, which makes the coating exhibit excellent corrosion resistance in complex petroleum environments.

[0013] Optionally, the ZIF-67@MXene core-shell nanosheets are prepared by the following method:

[0014] A. Add Ti3AlC2 powder to HF solution, stir at 30-40°C for 20-24 hours, then perform ultrasonic treatment, followed by centrifugation to obtain a monolayer MXene dispersion, add thiourea to the monolayer MXene dispersion, and react at 100-120°C for 10-12 hours to obtain a thiolated monolayer MXene dispersion;

[0015] B. Add 2-methylimidazole solution to cobalt nitrate solution, stir at room temperature for 30-60 min, then centrifuge to collect the precipitate, wash with methanol, and dry to obtain ZIF-67 nanoparticles;

[0016] C. ZIF-67 nanoparticles and thiol monolayer MXene dispersion were mixed and ultrasonically dispersed for 30-60 minutes, followed by stirring and reacting at room temperature for 10-12 hours. The mixture was then centrifuged, washed, and dried. The solid was heated to 550-600°C under a nitrogen atmosphere and kept at this temperature for 2-3 hours. After cooling, ZIF-67@MXene core-shell nanosheets were obtained.

[0017] The ZIF-67@MXene core-shell nanosheets prepared using this technical solution consist of a ZIF-67 core that, upon thermal decomposition, forms a porous carbon framework and cobalt-based nanoparticles. This porous structure adsorbs metal ions and promotes their uniform release. The cobalt particles act as catalytic sites, enhancing the uniformity of nickel, tungsten, and phosphorus co-deposition. The thiol-modified MXene shell exhibits excellent electrical conductivity, allowing for uniform current conduction and preventing uneven metal ion deposition caused by excessive local current density. The thiol groups act as "molecular bridges" to guide the orderly deposition of metal ions on the nanosheet surface, forming a uniform alloy coating.

[0018] Optionally, in step A, the mass concentration of the HF solution is 8%-10%; the mass ratio of the Ti3AlC2 powder to the HF solution is 1:(15-20).

[0019] By adopting the above technical solution, the HF solution concentration and the ratio of Ti3AlC2 and HF can accurately control the MXene layer exfoliation effect, ensuring that the monolayer rate meets the requirements, which is beneficial to improving the structural stability of ZIF-67@MXene core-shell nanosheets.

[0020] Optionally, in step A, the amount of thiourea added is 0.5%-0.8% of the mass of the monolayer MXene dispersion.

[0021] Optionally, in step B, the mass concentration of the 2-methylimidazole solution is 0.4-0.6 mol / L; the mass concentration of the cobalt nitrate solution is 0.08-0.12 mol / L; and the mass ratio of the 2-methylimidazole solution to the cobalt nitrate solution is (4-5):1.

[0022] Optionally, in step C, the mass ratio of the ZIF-67 nanoparticles to the thiolated monolayer MXene dispersion is 1:(2-4).

[0023] Optionally, the plasma mixed gas is Ar, O2 and CF4 in a volume ratio of 7:2:1.

[0024] Through this technical solution, Ar sputtering creates a regular array of grooves, providing mechanical locking sites and strengthening the mechanical bond between the coating and the substrate. O2 removes surface impurities through oxidation, improving the chemical bond between the coating and the substrate. CF4 introduces F⁻, selectively etching the metal surface, reducing surface energy, promoting plating solution wetting, and reducing pinhole defects. The synergistic effect of these three gases effectively increases the effective specific surface area of ​​the workpiece being plated, improves the bonding strength of the coating to the workpiece, and ensures a more secure adhesion of the coating to the workpiece surface. This helps improve the corrosion resistance and stability of the coating in complex environments.

[0025] Optionally, in S3, the parameters of the pulse current and the alternating magnetic field during the electroplating process are controlled as follows:

[0026] During the initial electroplating period of 0-30 minutes, a 1kHz pulse current with a duty cycle of 30%, an average current density of 3A / dm², an alternating magnetic field strength of 1.2T, and a frequency of 50Hz is applied to form a nanocrystalline transition layer.

[0027] During the middle stage of electroplating (31-60 minutes): a 3kHz pulse current with a duty cycle of 20%, an average current density of 4A / dm², an alternating magnetic field strength of 0.5T, and a frequency of 100Hz is applied to form an amorphous / nanocrystalline composite layer.

[0028] During the last 61-90 minutes of electroplating, a 5kHz pulse current with a duty cycle of 40%, an average current density of 5A / dm², an alternating magnetic field strength of 2T, and a frequency of 200Hz is applied to form an amorphous / nanocrystalline composite layer and a gradient nanocrystalline surface layer.

[0029] By adopting the above technical solution and setting the parameters of the pulse current and alternating magnetic field during the electroplating process, the porosity of the coating can be effectively reduced through the dual effects of the pulse current suppressing dendrites and the magnetic field promoting ion migration, thereby forming a dense coating structure with no holes or cracks. This results in excellent corrosion resistance in complex petroleum environments.

[0030] Optionally, the composite complexing agent comprises glycine and hydroxyethylidene diphosphonic acid in a mass ratio of 1:1.

[0031] By employing the above technical solution, a composite complexing agent composed of glycine and hydroxyethylidene diphosphonic acid in a 1:1 mass ratio can fully utilize their synergistic effect. Glycine and hydroxyethylidene diphosphonic acid form stable complexes with metal ions, controlling the release rate of metal ions and avoiding uneven deposition rates caused by concentration fluctuations, thereby reducing compositional inhomogeneities in the coating. This stable complexation helps produce a coating with uniform composition and a dense structure, improving its quality and performance, and enhancing its corrosion resistance and stability in complex environments.

[0032] Optionally, the specific formula of the electroplating solution is as follows:

[0033] 25-35 parts of nickel sulfate;

[0034] 30-40 parts of sodium tungstate;

[0035] 20-30 parts of sodium hypophosphite;

[0036] 0.5-2 parts of nano silicon carbide powder;

[0037] 1.5-3 parts of ZIF-67@MXene core-shell nanosheets;

[0038] 0.5-1 part of composite complexing agent;

[0039] The balance is 900-920 parts of water.

[0040] In summary, this application has the following beneficial effects:

[0041] 1. This application incorporates ZIF-67@MXene core-shell nanosheets into the electroplating solution formulation. The ZIF-67 core, upon thermal decomposition, forms a porous carbon framework and cobalt-based nanoparticles. This porous structure adsorbs metal ions and promotes their uniform release. The cobalt particles serve as catalytic sites, enhancing the uniformity of the co-deposition of nickel, tungsten, and phosphorus. Furthermore, the thiol-modified MXene shell exhibits excellent electrical conductivity, enabling uniform current conduction and preventing uneven metal ion deposition caused by localized high current density. The thiol groups act as "molecular bridges" to guide the orderly deposition of metal ions on the nanosheet surface. Furthermore, the coordination effect of the complexing agent (glycine + hydroxyethylidene diphosphonic acid) stabilizes the metal ions in a complexed ion form, preventing uneven deposition rates caused by concentration fluctuations and thus reducing compositional inhomogeneities within the coating. These factors work together to achieve a more uniform distribution of elements such as nickel, tungsten, and phosphorus within the coating, avoiding significant local variations in corrosion resistance. This improves the overall corrosion resistance of the coating in complex petroleum environments, enhancing its overall corrosion resistance.

[0042] 2. The electroplating process of the present application performs well in improving the density of the coating structure. Nano-silicon carbide powder serves as a nanoparticle reinforcement phase to refine the grains and fill the pores, further improving the structural density. Nano-SiC and ZIF-67@MXene jointly refine the grains through "particle filling + layer stacking". During the electroplating process, the pulse current and the alternating magnetic field work together. The pulse current inhibits dendrite growth, and the alternating magnetic field generates a Lorentz force to promote ion migration, further reducing the porosity of the coating. Moreover, at different stages of electroplating, by precisely controlling the parameters of the pulse current and the alternating magnetic field, such as forming a nanocrystalline transition layer in the early stage of electroplating, forming an amorphous / nanocrystalline composite layer in the middle stage, and forming a gradient nanocrystalline surface layer in the later stage, the microstructure of the coating is further optimized, forming a dense coating structure with "no holes and no cracks". This dense structure can effectively block the penetration of corrosive media, so that the coating exhibits excellent corrosion resistance in complex petroleum environments.

[0043] 3. The electroplating process of the present application improves the corrosion resistance of the coating in a complex petroleum environment by improving the uniformity of the coating composition and the structural density. The plasma mixed gas etching treatment increases the effective specific surface area of ​​the workpiece to be plated, improves the bonding force between the coating and the workpiece to be plated, and makes the coating more firmly adhere to the surface of the workpiece. During the electroplating process, a coating with uniform composition and dense structure is formed by means of measures such as the coordinated control of the ion deposition rate by a composite chelating agent and a pulse current, and the promotion of ion migration by an alternating magnetic field. When facing an environment with high temperature, high pressure, high salinity and rich in corrosive media such as hydrogen sulfide and carbon dioxide in oil extraction operations, this coating can effectively resist the erosion of corrosive media and avoid the occurrence of local corrosion perforation and substrate corrosion. Compared with traditional nickel tungsten phosphorus coatings and electroplating processes, the coating of the present application has better corrosion resistance and stability in a complex petroleum environment, providing a strong guarantee for the long-term stable operation of petroleum machinery and equipment, and reducing maintenance costs. DETAILED DESCRIPTION

[0044] The present application is further described in detail below with reference to the embodiments.

[0045] Preparation example of ZIF-67@MXene core-shell nanosheets

[0046] Preparation Example 1

[0047] ZIF-67@MXene core-shell nanosheets were prepared by the following method:

[0048] A. Add 1 kg of Ti3AlC2 powder to 15 kg of 8% HF solution, stir at 30 ° C for 20 h, then ultrasonicate at 300 W power for 3 h, and then centrifuge at 3000 rpm to collect the supernatant to obtain a monolayer MXene dispersion. Add 50 g of thiourea to 10 kg of the monolayer MXene dispersion and react at 100 ° C for 10 h to obtain a thiolated monolayer MXene dispersion.

[0049] B. Add 4 kg of 0.4 mol / L 2-methylimidazole solution to 1 kg of 0.08 mol / L cobalt nitrate solution, stir at 5000 rpm for 30 min, then centrifuge and collect the precipitate, wash with methanol, and dry to obtain ZIF-67 nanoparticles;

[0050] C. 1 kg of ZIF-67 nanoparticles and 2 kg of thiolated monolayer MXene dispersion were mixed and ultrasonically dispersed for 30 min. Then, the mixture was stirred and reacted at room temperature for 10 h. The mixture was then centrifuged, washed, and dried. The solid was heated to 550°C under a nitrogen atmosphere and kept warm for 2 h. After cooling, ZIF-67@MXene core-shell nanosheets were obtained.

[0051] Preparation Example 2

[0052] ZIF-67@MXene core-shell nanosheets were prepared by the following method:

[0053] A. Add 1 kg of Ti3AlC2 powder to 18 kg of 9% HF solution, stir at 35 °C for 22 h, then ultrasonicate at 300 W for 3 h, and then centrifuge at 3000 rpm to collect the supernatant to obtain a monolayer MXene dispersion. Add 65 g of thiourea to 10 kg of the monolayer MXene dispersion and react at 110 °C for 11 h to obtain a thiolated monolayer MXene dispersion.

[0054] B. Add 4.5 kg of 0.5 mol / L 2-methylimidazole solution to 1 kg of 0.10 mol / L cobalt nitrate solution, stir at 5000 rpm for 30 min, then centrifuge and collect the precipitate, wash with methanol, and dry to obtain ZIF-67 nanoparticles;

[0055] C. 1 kg of ZIF-67 nanoparticles and 3 kg of thiolated monolayer MXene dispersion were mixed and ultrasonically dispersed for 40 min. The mixture was then stirred and reacted at room temperature for 11 h. The mixture was then centrifuged, washed, and dried. The solid was heated to 580 °C under a nitrogen atmosphere and kept at this temperature for 2.5 h. After cooling, ZIF-67@MXene core-shell nanosheets were obtained.

[0056] Preparation Example 3

[0057] ZIF-67@MXene core-shell nanosheets were prepared by the following method:

[0058] A. Add 1 kg of Ti3AlC2 powder to 20 kg of 10% HF solution, stir at 40 ° C for 24 hours, then ultrasonicate at 300 W power for 3 hours, and then centrifuge at 3000 rpm to collect the supernatant to obtain a monolayer MXene dispersion. Add 80 g of thiourea to 10 kg of the monolayer MXene dispersion and react at 120 ° C for 12 hours to obtain a thiolated monolayer MXene dispersion.

[0059] B. Add 5 kg of 0.6 mol / L 2-methylimidazole solution to 1 kg of 0.12 mol / L cobalt nitrate solution, stir at 5000 rpm for 30 min, then centrifuge and collect the precipitate, wash with methanol, and dry to obtain ZIF-67 nanoparticles;

[0060] C. 1 kg of ZIF-67 nanoparticles and 4 kg of thiolated monolayer MXene dispersion were mixed and ultrasonically dispersed for 60 min. Then, the mixture was stirred and reacted at room temperature for 12 h. The mixture was then centrifuged, washed, and dried. The solid was heated to 600 °C under a nitrogen atmosphere and kept at this temperature for 3 h. After cooling, ZIF-67@MXene core-shell nanosheets were obtained.

[0061] Example

[0062] The workpiece to be plated used in the embodiment of the present application is a 304 stainless steel oil well pipe with an outer diameter of 114.30 mm and a wall thickness of 9.50 mm.

[0063] Example 1

[0064] A nickel-tungsten-phosphorus coating electroplating process comprises the following steps:

[0065] S1. Weigh the raw materials according to the ratio shown in Table 1, then mix the raw materials in Table 1 and stir for 5 minutes to obtain a composite electroplating solution, wherein the ZIF-67@MXene core-shell nanosheets are prepared in Preparation Example 1, and the composite complexing agent is glycine and hydroxyethylidene diphosphonic acid in a mass ratio of 1:1;

[0066] S2, using plasma mixed gas to etch the surface of the workpiece to be plated, the plasma mixed gas is Ar, O2 and CF4 with a volume ratio of 7:2:1; the etching pressure is 50Pa, and the processing time is 20min;

[0067] S3. A three-electrode system is used, with the working electrode being the etched workpiece, the reference electrode being a saturated calomel electrode, and the auxiliary anode being a meshed platinum-titanium electrode. The temperature of the composite electroplating solution is maintained at 65°C, the circulation flow rate is 2.5 L / min, and the composite electroplating solution is stirred at a frequency of 40 kHz during the electroplating process. Electroplating is performed on the workpiece to be plated after the surface treatment under the action of pulse current and alternating magnetic field. The parameters of the pulse current and alternating magnetic field during the electroplating process are controlled as follows: in the initial electroplating period of 0-30 minutes: applying a 1kHz pulse current, a duty cycle of 30%, an average current density of 3A / dm², an alternating magnetic field strength of 1.2T, and a frequency of 50Hz to form a nanocrystalline transition layer; in the middle electroplating period of 31-60 minutes: applying a 3kHz pulse current, a duty cycle of 20%, an average current density of 4A / dm², an alternating magnetic field strength of 0.5T, and a frequency of 100Hz to form an amorphous / nanocrystalline composite layer; in the late electroplating period of 61-90 minutes: applying a 5kHz pulse current, a duty cycle of 40%, an average current density of 5A / dm², an alternating magnetic field strength of 2T, and a frequency of 200Hz to form an amorphous / nanocrystalline composite layer and a gradient nanocrystalline surface layer;

[0068] S4. Place the electroplated workpiece in a quartz furnace. Under nitrogen protection, heat it to 200°C at a heating rate of 5°C / min and keep it warm for 30 minutes. Then continue to heat it to 350°C at a heating rate of 3°C / min and keep it warm for 60 minutes. Then heat it to 450°C at a heating rate of 2°C / min and keep it warm for 120 minutes. Then cool it naturally.

[0069] Example 2

[0070] A nickel-tungsten-phosphorus coating electroplating process comprises the following steps:

[0071] S1. Weigh the raw materials according to the ratio shown in Table 1, then mix the raw materials in Table 1 and stir for 5 minutes to obtain a composite electroplating solution, wherein the ZIF-67@MXene core-shell nanosheets are prepared in Preparation Example 2, and the composite complexing agent is glycine and hydroxyethylidene diphosphonic acid in a mass ratio of 1:1;

[0072] S2. Etching the surface of the workpiece to be plated is performed using a plasma mixed gas, wherein the plasma mixed gas is Ar, O2 and CF4 in a volume ratio of 7:2:1; the etching pressure is 80 Pa, and the processing time is 18 minutes;

[0073] S3. A three-electrode system is used. The working electrode is the etched workpiece, the reference electrode is a saturated calomel electrode, and the auxiliary anode is a meshed platinum-titanium electrode. The temperature of the composite electroplating solution is maintained at 68°C, the circulation flow rate is 2.5L / min, and the composite electroplating solution is stirred at a frequency of 40kHz during the electroplating process. Electroplating is performed on the workpiece to be plated after the surface treatment under the action of pulse current and alternating magnetic field. The parameters of the pulse current and alternating magnetic field during the electroplating process are controlled as follows: in the initial electroplating period of 0-30 minutes: applying a 1kHz pulse current, a duty cycle of 30%, an average current density of 3A / dm², an alternating magnetic field strength of 1.2T, and a frequency of 50Hz to form a nanocrystalline transition layer; in the middle electroplating period of 31-60 minutes: applying a 3kHz pulse current, a duty cycle of 20%, an average current density of 4A / dm², an alternating magnetic field strength of 0.5T, and a frequency of 100Hz to form an amorphous / nanocrystalline composite layer; in the late electroplating period of 61-90 minutes: applying a 5kHz pulse current, a duty cycle of 40%, an average current density of 5A / dm², an alternating magnetic field strength of 2T, and a frequency of 200Hz to form an amorphous / nanocrystalline composite layer and a gradient nanocrystalline surface layer;

[0074] S4. Place the electroplated workpiece in a quartz furnace. Under nitrogen protection, heat it to 200°C at a heating rate of 5°C / min and keep it warm for 30 minutes. Then continue to heat it to 350°C at a heating rate of 3°C / min and keep it warm for 60 minutes. Then heat it to 450°C at a heating rate of 2°C / min and keep it warm for 120 minutes. Then cool it naturally.

[0075] Example 3

[0076] A nickel-tungsten-phosphorus coating electroplating process comprises the following steps:

[0077] S1. Weigh the raw materials according to the ratio shown in Table 1, then mix the raw materials in Table 1 and stir for 5 minutes to obtain a composite electroplating solution, wherein the ZIF-67@MXene core-shell nanosheets are prepared in Preparation Example 3, and the composite complexing agent is glycine and hydroxyethylidene diphosphonic acid in a mass ratio of 1:1;

[0078] S2. Etching the surface of the workpiece to be plated is performed using a plasma mixed gas, wherein the plasma mixed gas is Ar, O2 and CF4 in a volume ratio of 7:2:1; the etching pressure is 100 Pa, and the processing time is 15 minutes;

[0079] S3. A three-electrode system is used, with the working electrode being the etched workpiece, the reference electrode being a saturated calomel electrode, and the auxiliary anode being a meshed platinum-titanium electrode. The temperature of the composite electroplating solution is maintained at 70°C, the circulation flow rate is 2.5 L / min, and the composite electroplating solution is stirred at a frequency of 40 kHz during the electroplating process. Electroplating is performed on the workpiece to be plated after the surface treatment under the action of pulse current and alternating magnetic field. The parameters of the pulse current and alternating magnetic field during the electroplating process are controlled as follows: in the initial electroplating period of 0-30 minutes: applying a 1kHz pulse current, a duty cycle of 30%, an average current density of 3A / dm², an alternating magnetic field strength of 1.2T, and a frequency of 50Hz to form a nanocrystalline transition layer; in the middle electroplating period of 31-60 minutes: applying a 3kHz pulse current, a duty cycle of 20%, an average current density of 4A / dm², an alternating magnetic field strength of 0.5T, and a frequency of 100Hz to form an amorphous / nanocrystalline composite layer; in the late electroplating period of 61-90 minutes: applying a 5kHz pulse current, a duty cycle of 40%, an average current density of 5A / dm², an alternating magnetic field strength of 2T, and a frequency of 200Hz to form a gradient nanocrystalline surface layer;

[0080] S4. Place the electroplated workpiece in a quartz furnace. Under nitrogen protection, heat it to 200°C at a heating rate of 5°C / min and keep it warm for 30 minutes. Then continue to heat it to 350°C at a heating rate of 3°C / min and keep it warm for 60 minutes. Then heat it to 450°C at a heating rate of 2°C / min and keep it warm for 120 minutes. Then cool it naturally.

[0081] Table 1 Raw material components and ratios of the composite electroplating solutions in Examples 1-3 (g)

[0082]

[0083] Example 4

[0084] A nickel-tungsten-phosphorus electroplating process is different from Example 1 in that the plasma mixed gas in S2 is Ar, O2 and CF4 in a volume ratio of 4:4:2.

[0085] Example 5

[0086] A nickel-tungsten-phosphorus electroplating process differs from Example 1 in that: in S3, the parameters of the pulse current and the alternating magnetic field during the electroplating process are controlled as follows: in the initial electroplating period of 0-30 minutes: applying a 5kHz pulse current, a duty cycle of 30%, an average current density of 5A / dm², an alternating magnetic field strength of 0.5T, and a frequency of 50Hz to form a nanocrystalline transition layer; in the middle electroplating period of 31-60 minutes: applying a 3kHz pulse current, a duty cycle of 20%, an average current density of 4A / dm², an alternating magnetic field strength of 1.0T, and a frequency of 100Hz to form an amorphous / nanocrystalline composite layer; in the late electroplating period of 61-90 minutes: applying a 1kHz pulse current, a duty cycle of 40%, an average current density of 3A / dm², an alternating magnetic field strength of 2T, and a frequency of 200Hz to form a gradient nanocrystalline surface layer.

[0087] Comparative Example

[0088] Comparative Example 1

[0089] A nickel-tungsten-phosphorus coating electroplating process is different from Example 1 in that: in this comparative example S1, ZIF-67@MXene core-shell nanosheets are not added to the composite electroplating solution, and the difference is supplemented with water.

[0090] Comparative Example 2

[0091] A nickel-tungsten-phosphorus coating electroplating process is different from Example 1 in that: in this comparative example S1, nano-silicon carbide powder is not added to the composite electroplating solution, and the difference is supplemented with water.

[0092] Comparative Example 3

[0093] A nickel-tungsten-phosphorus coating electroplating process is different from Example 1 in that: this comparative example does not perform step S2, that is, the workpiece to be plated is not etched, and in S3, the unetched workpiece to be plated is directly used for electroplating.

[0094] Comparative Example 4

[0095] A nickel-tungsten-phosphorus electroplating process is provided, which differs from Example 1 in that no alternating magnetic field is provided in this comparative example S3.

[0096] Performance testing

[0097] Test samples: workpieces after electroplating in Examples 1-5 and Comparative Examples 1-4.

[0098] 1. Bonding strength

[0099] Refer to the ASTM D4541 standard, apply vertical tension to the workpiece until the coating peels off, and measure the maximum tension at the time of peeling to evaluate the bonding strength.

[0100] 2. Porosity

[0101] Place the workpiece in a 5% sodium chloride solution and let it stand at 30°C for 48 hours. Take out the sample, rinse the surface with clean water, and observe it under a microscope after drying. Record the number of corrosion spots with a diameter ≥ 0.1 mm.

[0102] 3. Corrosion resistance

[0103] To simulate the high-temperature, high-pressure, H2S / CO2 coexistence environment found in oil production, a 3.5% NaCl solution was used as the medium to simulate high salinity. H2S (partial pressure 0.1 MPa) and CO2 (partial pressure 0.5 MPa) were introduced, and the pH was adjusted to 5.5. The medium system temperature was 120°C and the pressure was 10 MPa to simulate downhole high pressure. The sample was then placed in an autoclave, the medium was introduced, and the temperature and pressure were increased to the set conditions. The conditions were maintained for 720 hours. The sample was then removed, rinsed with deionized water, dried, and weighed. The corrosion weight loss rate was calculated.

[0104] Table 2 Test results

[0105]

[0106] Test data shows that Examples 1-3, due to their complete adoption of the present process, excel in all performance indicators. Their bonding strength reaches 84.5-86.7 MPa, a significant improvement over conventional processes. This is due to the synergistic effect of ZIF-67@MXene core-shell nanosheets and plasma etching on the enhanced adhesion between the coating and the substrate. The number of corrosion points is only 4-5 per dm², and the corrosion weight loss rate is as low as 0.32%-0.36%. This demonstrates the key role of nano-silicon carbide, composite complexing agents, and pulsed current-alternating magnetic field control in improving compositional uniformity and structural density, effectively blocking the penetration of corrosive media.

[0107] By comparing Examples 4 and 5 with Comparative Examples 1-4, we can clearly see the impact of process parameters and the lack of core materials on performance. After adjusting the plasma gas ratio in Example 4, the bonding strength dropped to 75.2MPa and the corrosion weight loss rate increased to 0.81%, indicating that the imbalance of the gas ratio will destroy the surface uniformity; Example 5 changes the pulse current and magnetic field parameters, resulting in insufficient optimization of the microstructure of the coating and reduced corrosion resistance. Comparative Example 1 did not add core-shell nanosheets, and the bonding strength dropped sharply to 48.8MPa, and the corrosion weight loss rate reached 1.35%; Comparative Example 2 lacked nano-silicon carbide, and the number of corrosion points increased to 32 / dm², all of which confirmed the decisive role of key materials in the density and corrosion resistance of the coating.

[0108] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A nickel-tungsten-phosphorus coating electroplating process, characterized in that: The steps include: S1. Preparing a nanocomposite electroplating solution, wherein the composite electroplating solution comprises nickel salt, tungstate, hypophosphite, nano-silicon carbide powder, ZIF-67@MXene core-shell nanosheets, a composite complexing agent, and water; S2, using plasma mixed gas to etch the surface of the workpiece to be plated, the etching pressure is 50-100Pa, and the processing time is 15-20min; S3. Controlling the plating solution temperature at 65-70°C, electroplating the surface-treated workpiece under the action of a pulse current and an alternating magnetic field, wherein the pulse current has a frequency of 1-5 kHz, a duty cycle of 20%-40%, an average current density of 3-5 A / dm², an alternating magnetic field strength of 0.5-2 T, and a frequency of 50-200 Hz, and ultrasonically stirring the composite plating solution during the electroplating process; S4. Under nitrogen protection, anneal the workpiece.

2. The nickel-tungsten-phosphorus electroplating process according to claim 1, characterized in that: The ZIF-67@MXene core-shell nanosheets were prepared by the following method: A. Add Ti3AlC2 powder to HF solution, stir at 30-40°C for 20-24 hours, then perform ultrasonic treatment, followed by centrifugation to obtain a monolayer MXene dispersion, and add thiourea to the monolayer MXene dispersion to react to obtain a thiolated monolayer MXene dispersion; B. Add 2-methylimidazole solution to cobalt nitrate solution, stir at room temperature for 30-60 min, then centrifuge to collect the precipitate, wash with methanol, and dry to obtain ZIF-67 nanoparticles; C. ZIF-67 nanoparticles and thiolated monolayer MXene dispersion were mixed, stirred and reacted for 10-12 hours after ultrasonication, and then centrifuged. The solid was washed and dried, and the solid was heated to 550-600°C under a nitrogen atmosphere and kept warm for 2-3 hours. After cooling, ZIF-67@MXene core-shell nanosheets were obtained.

3. The nickel-tungsten-phosphorus electroplating process according to claim 2, characterized in that: In step A, the mass concentration of the HF solution is 8%-10%; the mass ratio of the Ti3AlC2 powder to the HF solution is 1:(15-20).

4. The nickel-tungsten-phosphorus electroplating process according to claim 3, characterized in that: In step A, the amount of thiourea added is 0.5%-0.8% of the mass of the monolayer MXene dispersion.

5. The nickel-tungsten-phosphorus electroplating process according to claim 4, characterized in that: In step B, the mass concentration of the 2-methylimidazole solution is 0.4-0.6 mol / L; the mass concentration of the cobalt nitrate solution is 0.08-0.12 mol / L; and the mass ratio of the 2-methylimidazole solution to the cobalt nitrate solution is (4-5):

1.

6. The nickel-tungsten-phosphorus electroplating process according to claim 5, characterized in that: In step C, the mass ratio of the ZIF-67 nanoparticles to the thiolated monolayer MXene dispersion is 1:(2-4).

7. The nickel-tungsten-phosphorus electroplating process according to claim 1, characterized in that: The plasma mixed gas is Ar, O2 and CF4 in a volume ratio of 7:2:

1.

8. The nickel-tungsten-phosphorus electroplating process according to claim 1, characterized in that: In S3, the parameters of the pulse current and alternating magnetic field during the electroplating process are controlled as follows: During the initial electroplating period of 0-30 minutes, a 1kHz pulse current with a duty cycle of 30%, an average current density of 3A / dm², an alternating magnetic field strength of 1.2T, and a frequency of 50Hz is applied to form a nanocrystalline transition layer. During the middle stage of electroplating (31-60 minutes): a 3kHz pulse current with a duty cycle of 20%, an average current density of 4A / dm², an alternating magnetic field strength of 0.5T, and a frequency of 100Hz is applied to form an amorphous / nanocrystalline composite layer. During the last 61-90 minutes of electroplating, a 5kHz pulse current with a duty cycle of 40%, an average current density of 5A / dm², an alternating magnetic field strength of 2T, and a frequency of 200Hz is applied to form an amorphous / nanocrystalline composite layer and a gradient nanocrystalline surface layer.

9. The nickel-tungsten-phosphorus electroplating process according to claim 1, characterized in that: The composite complexing agent comprises glycine and hydroxyethylidene diphosphonic acid in a mass ratio of 1:

1.

10. The nickel-tungsten-phosphorus electroplating process according to claim 1, characterized in that: The specific formula of the electroplating solution is as follows: 25-35 parts of nickel sulfate; 30-40 parts of sodium tungstate; 20-30 parts of sodium hypophosphite; 0.5-2 parts of nano silicon carbide powder; 1.5-3 parts of ZIF-67@MXene core-shell nanosheets; 0.5-1 part of composite complexing agent; The balance is 900-920 parts of water.

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