Tungsten alloy coating and method for manufacturing same, and perforated liner

Abstract

The present application relates to alloy plating technical field, specifically relates to a tungsten alloy plating and its preparation method, and a hole lining pipe, the tungsten alloy plating is tungsten nickel alloy plating, plating is dense and has no defect, thickness is 40~100 μm, and Vickers hardness is not less than 900 HV1, the plating uses nickel sulfamate and sodium tungstate as main salt, is supplemented with specific composite complexing agent, conductive salt, buffer and additive, forms stable electroplating solution, is cleaned through plasma, and is combined with profiling anode and pulse electroplating technology, and is carried out electroplating under the matching pulse parameter and mechanical stirring.The method can deposit the high-hardness tungsten alloy plating of thickness uniformity, excellent performance on the inner wall, outer wall and all hole inner surface of the hole lining pipe of complex shape workpiece, in particular, solves the technical problem of uniformity of surface plating of deep hole and complex structure parts.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of alloy plating, in particular to a tungsten alloy plating layer, a preparation method thereof and a perforated liner pipe. BACKGROUND

[0002] Tungsten-nickel alloy plating layer has a wide application prospect in aerospace, petrochemical industry, precision mold and other industrial fields due to its high hardness, corrosion resistance and high temperature stability. In particular, on the perforated liner pipe in the petroleum industry, a layer of hard tungsten alloy plating layer can significantly improve its sand erosion resistance and washing resistance, thereby prolonging the service life.

[0003] Currently, the preparation of tungsten-nickel alloy plating layer mainly adopts electrodeposition technology. However, the existing electroplating process still faces many technical challenges in realizing high-quality plating layer, especially in the application on complex structure workpieces. Conventional electroplating technology is prone to cause uneven thickness of the plating layer at the edge of the hole, the deep inner wall and other parts of the workpiece, such as the perforated liner pipe, due to uneven electric field distribution and limited mass transfer. The edge of the hole is often too thick due to edge effect, and even burrs are generated, while the inside of the hole and the center of the deep hole are too thin due to weak electric lines, which cannot form effective protection, seriously affecting the overall performance and service life of the workpiece; the traditional nickel-tungsten electroplating system, such as using nickel chloride or nickel sulfate as the main salt, has a high internal stress of the obtained plating layer, which is prone to produce micro-cracks or even peeling when depositing a thick plating layer, such as 40 μm or more, and the plating layer has insufficient density, which is prone to defects such as holes and slag inclusion, thereby reducing its corrosion resistance and mechanical strength; tungsten is a metal that is difficult to be electrodeposited from aqueous solution alone, and its co-deposition with nickel strongly depends on the complexing agent system in the electroplating solution. The existing complexing system uses a single citrate salt, which has insufficient stability or efficiency, which may lead to spontaneous decomposition of the electroplating solution, poor leveling ability, and inability to obtain an alloy plating layer with high tungsten content and stable performance. Finally, the process uses direct current electroplating, which has poor coverage ability for deep holes and grooves of complex workpieces. Although pulse electroplating technology has been proved to be helpful to improve the quality of the plating layer, it is still difficult to obtain a high-performance plating layer with uniform thickness on each surface of the three-dimensional complex structure without combining with an optimized electroplating solution formulation and a special tooling, such as a profiled anode.

[0004] CN102337569B discloses a preparation method of a cobalt-tungsten nano-alloy coating. A mixed solution of 100-200 g / L of cobalt sulfate, 10-70 g / L of sodium tungstate, 50-150 g / L of sodium sulfate, 15-50 g / L of boric acid, 1-4 g / L of sodium saccharin, 0.01-0.1 g / L of a surfactant, and 40-120 g / L of a complexing agent is used as an electrolyte for electroplating with platinum titanium or cobalt-tungsten alloy as an anode and a workpiece to be plated as a cathode. The alloy coating has a nanocrystalline structure with a grain size of 20-40 nm, and the tungsten content in the nano-alloy coating is 13.2-25.1 wt%. The preparation method of the coating is simple, and the coating has not only the hardness of hard chromium coating but also better wear resistance and friction reduction performance than hard chromium coating. The coating is suitable for parts requiring high hardness, high wear resistance, and low friction coefficient, and has wide application.

[0005] CN105543910B discloses a nickel-tungsten alloy composite coating, and a preparation method thereof. The preparation method comprises the following steps: (1) preparation of an electroplating solution: sodium citrate, NH4Cl, NaBr, Na2WO4·2H2O, NiSO4·6H2O, and β-cyclodextrin are sequentially added into deionized water and mixed uniformly; (2) a 45# carbon steel substrate is polished with 400, 800, and 1200 mesh sandpaper in sequence, the polished steel sheet is activated in 1 mol / L sulfuric acid, and then is electroplated in the electroplating solution; and (3) a pulse electrodeposition method is adopted in the electroplating process, the deposition current density is 5 A / dm 2 , the duty cycle is 0.8, and the deposition time is 1 h. The β-cyclodextrin is used as a grain refiner for electroplating nickel-tungsten alloy, the grain size of the nickel-tungsten alloy is obviously reduced in the deposition process, the substance is stable in the preparation process and does not affect the performance of the product, and the coating has better corrosion resistance.

[0006] In summary, the current preparation method of the tungsten alloy coating has not involved key problems such as complex-shaped workpieces and stability of the electroplating solution, and therefore, there is an urgent need for a new tungsten alloy coating and a preparation method thereof, which can effectively solve the problems of high internal stress of the coating and poor thickness uniformity on complex geometrical shapes without sacrificing the core performance such as hardness of the coating, so as to meet the high-standard application requirements of precision parts such as a perforated liner. SUMMARY

[0007] To solve the above problems, the application provides a tungsten alloy coating and a preparation method thereof. The tungsten alloy coating is a tungsten-nickel alloy coating. The preparation method uses nickel sulfamate and sodium tungstate as main salts, and is supplemented with specific composite complexing agents, conductive salts, buffering agents and additives to form a stable electroplating solution. The electroplating solution is subjected to plasma cleaning, and then electroplating is performed under matched pulse parameters and mechanical stirring by combining a profiled anode and a pulse electroplating technology. The method can deposit a high-hardness tungsten alloy coating with uniform thickness and excellent performance on the inner wall, outer wall and all hole inner surfaces of a workpiece with complex shape, especially a hole lining tube.

[0008] Specifically, the tungsten alloy coating is made of nickel-tungsten alloy, characterized in that the coating is dense and defect-free, has a thickness of 40-100 microns, and a Vickers hardness of not less than 900 HV1.

[0009] Step (1): prepare electroplating solution raw materials according to mass parts: 80-120 parts of nickel sulfamate, 70-100 parts of sodium tungstate, 60-100 parts of composite complexing agents, 10-30 parts of conductive salts, 10-20 parts of buffering agents, 0.5-3 parts of stress relieving agents, 0.1-1 part of brighteners, 0.1-0.5 parts of surfactants, 0.5-5 parts of rare earth salts and 1000 parts of deionized water;

[0010] The rare earth salt is pre-mixed with 1 / 3-1 / 2 of the composite complexing agents and added to the deionized water. After complete dissolution, the remaining components are added, and after complete dissolution, the mixture is stirred uniformly and filtered to obtain the electroplating solution. The electroplating solution is placed in an electroplating tank, and the temperature is maintained at 60-70°C, and the pH value is 8.0-9.0.

[0011] Step (2): after oil removal and acid activation of the hole lining tube, the hole lining tube is subjected to argon plasma bombardment cleaning in a vacuum environment;

[0012] Step (3): the hole lining tube obtained in step (2) is used as a cathode and placed in the electroplating tank, and a profiled anode matching the substrate profile is used for electroplating under pulse current and mechanical stirring;

[0013] Step (4): after electroplating, the workpiece is taken out, washed with deionized water, and then placed in a forced air drying oven for 20-40 minutes at 80-120°C with circulating hot air.

[0014] Preferably, in step (1), the composite complexing agent is a system composed of citrate and ethylenediaminetetraacetic acid in a mass ratio of 3-5:1.

[0015] Different complexing agents have different complexing abilities for different metal ions. Mixed use can better balance the deposition potentials of nickel and tungsten, making them closer, and can simultaneously consider the stability of the electroplating solution, the deposition rate and the coating quality.

[0016] As preferred, in step (1), the conductive salt is nickel sulfate, the buffer is boric acid, the stress reliever is sodium saccharin, the brightener is propargyl alcohol, and the surfactant is sodium dodecyl sulfate;

[0017] As preferred, in step (1), the rare earth salt is cerium nitrate.

[0018] The rare earth ion Ce 3+ The adsorption on the growth point can inhibit the rapid growth of the crystal grains, promote the formation of nanocrystalline or amorphous structure, and thus significantly improve the hardness, compactness and corrosion resistance of the plating layer. 3+ By refining the crystal grains and improving the deposition process, the intrinsic internal stress of the plating layer can be effectively reduced, and the crack generation can be prevented.

[0019] The present application uses nickel sulfamate and sodium tungstate as main salts, and provides driving force for nickel-tungsten co-deposition in thermodynamics, and has the advantages that: a citrate-ethylenediaminetetraacetic acid complexing agent system is adopted, the system can form complex compounds with different stabilities with nickel ions and tungstate ions respectively through synergistic effect, not only inhibits the precipitation of tungstic acid, ensures the long-period stability of the electroplating solution, but also adjusts the activity and reduction rate of the two kinds of metal ions in the cathode diffusion layer, promotes the uniform co-deposition of nickel and tungsten at the atomic scale, so that a non-defective amorphous or microcrystalline nickel-tungsten alloy plating layer with uniform composition and dense structure can be obtained. At the same time, the stress reliever, surfactant and other additives are supplemented, and the rare earth salt is mixed with the complexing agent in advance, so that the crystal grains are further refined, the internal stress is reduced, the introduction of chloride ions is avoided, the source of inducing post-pitting is fundamentally eliminated, the long-term stability of the plating layer in the corrosion environment is significantly improved, and finally the high hardness, high compactness and excellent corrosion resistance of the plating layer are ensured.

[0020] As preferred, in step (2), the specific steps of the plasma cleaning of the perforated liner pipe are as follows: S1, placing the perforated liner pipe subjected to preliminary oil removal and acid activation on the cathode tray of the vacuum chamber, ensuring that the substrate axis is parallel to the airflow direction to facilitate uniform plasma penetration, closing and sealing the chamber door, S2, starting the mechanical pump and molecular pump set, and pumping the background vacuum degree of the vacuum chamber to not less than 5x10 -3Pa, S3, high-purity argon is introduced into the vacuum chamber as a process gas, the gas flow is accurately controlled at 150-250 ml / min through a mass flow controller, and the working pressure in the chamber is stabilized at 30-60 Pa through a throttle valve, S4, after the vacuum degree and the gas flow are stabilized, radio frequency power with a frequency of 13.56 MHz is applied to the cathode tray, the power is set at 800-1500 W, and the processing time lasts for 10-20 min, S5, after the processing is completed, the radio frequency power source is first turned off to stop the plasma generation, then the process gas is stopped, then high-purity nitrogen is recharged into the chamber until the normal pressure is restored, and finally the chamber door is opened, the processed perforated liner is quickly taken out and immediately transferred to the electroplating process to avoid surface recontamination;

[0021] Preferably, in step (3), the profiled anode is a nickel plate, the pulse current density is 6-12 ASD, the pulse frequency is 500-1500 Hz, the duty cycle is 25%-35%, the electroplating time is 90-150 min, and the stirring rate is 150-250 r / min.

[0022] A perforated liner includes a pipe body and a plurality of eyelets arranged on the pipe body, the inner wall, the outer wall and the inner surface of all the eyelets of the pipe body are covered with a tungsten alloy plating layer which is dense and defect-free, has a thickness of 40-100 mu m and a Vickers hardness of not less than 900 HV1.

[0023] Preferably, the ratio of the thickness of the tungsten alloy plating layer at the eyelets to the average thickness of the inner wall of the pipe body is 0.85-1.05.

[0024] The present application uses plasma cleaning technology to not only remove physically adsorbed contaminants, but also activates the substrate surface on an atomic scale through high-energy particle bombardment, enhances the chemical bonding and physical adhesion of the plating layer and the substrate, uses a profiled anode and a pulse current to optimize the primary current distribution from the geometric configuration, makes the electric field lines tend to be uniform on the complex profile surface, overcomes the edge effect, simultaneously optimizes the mass transfer process in the cathode diffusion layer through the concentration recovery effect of the pulse interval, and promotes the formation of crystal nuclei and inhibits the growth of crystal grains through instantaneous high current density, so as to realize the fine microstructure and high uniformity of the macro thickness of the plating layer. The circulating hot air drying orderly removes the moisture in the plating layer micro-pores through controllable heat input, avoids the stress caused by rapid vaporization of moisture, and may promote slight relaxation of atoms in the plating layer, further releases internal stress and stabilizes the plating layer structure.

[0025] The technical scheme forms an amorphous composite structure with uniform components, avoids introducing chloride ions to fundamentally improve the long-term stability of the plating layer in a corrosive environment, and the rare earth salt is selectively adsorbed at a growth interface due to its unique electronic layer structure, thereby effectively reducing the deposition overpotential of tungsten, promoting co-deposition, and achieving grain refinement and structure densification; the plasma cleaning realizes interface purification and lattice activation at an atomic scale, thereby providing guarantee for obtaining a weak-interface-free metallurgical-grade bond, and the synergistic effect of the profiled anode and the pulse current breaks through the edge effect of the complex structure from the field dimension, and the pulse current promotes nucleation and ion replenishment in the relaxation period through transient high-energy input, thereby achieving thickness uniformity and structural integrity in the deep-hole region.

[0026] Compared with the prior art, the present application has the following advantages:

[0027] 1. The synergistic effect of the profiled anode and the pulse power source solves the problem of uniformity of the electric field distribution at the deep hole, inner wall and hole edge of the perforated tube, so that the plating layer can ignore the shielding effect of the complex geometric structure and realize uniform coverage from the macroscopic scale to the micro profile.

[0028] 2. The synergistic regulation effect of the rare earth salt and the complexing agent system not only reduces the deposition energy barrier of the key elements through interface adsorption, but also stabilizes the electroplating solution chemical environment together with the complexing agent, thereby realizing stable co-deposition of high tungsten content, refining the microstructure of the plating layer, maintaining low internal stress while achieving excellent hardness, and achieving the unity of strengthening and high corrosion resistance that traditional technology cannot achieve. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The micro-morphology diagram of the tungsten alloy plating layer described in Example 1 of the present application;

[0030] Figure 2 The micro-morphology diagram of the tungsten alloy plating layer described in Comparative Example 3 of the present application;

[0031] Figure 3 The micro-morphology diagram of the tungsten alloy plating layer described in Comparative Example 4 of the present application; DETAILED DESCRIPTION

[0032] The following describes the embodiments of the present application by specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosed content. Obviously, the described examples are part of the embodiments of the present application, not all. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0033] The conductive salt is nickel sulfate;

[0034] The buffering agent is boric acid;

[0035] The stress reliever is sodium saccharin;

[0036] The brightener is propargyl alcohol;

[0037] The surfactant is sodium dodecyl sulfate.

[0038] Example 1

[0039] A tungsten alloy plated perforated liner pipe was prepared by the following steps:

[0040] Step (1): Prepare the raw materials of the electroplating solution by mass fraction: 100 parts of nickel sulfamate, 90 parts of sodium tungstate, 80 parts of complexing agent, 20 parts of conductive salt, 15 parts of buffering agent, 2 parts of stress reliever, 0.5 parts of brightener, 0.3 parts of surfactant, 3 parts of rare earth salt, and 1000 parts of deionized water. The complexing agent is composed of citrate and ethylenediaminetetraacetic acid in a mass ratio of 4:1, and the rare earth salt is cerium nitrate.

[0041] Prepare the electroplating solution according to the ratio, pre-mix the rare earth salt with 1 / 2 of the complexing agent and add it to the deionized water, completely dissolve it, then add the remaining components, fully dissolve, stir evenly and filter to obtain the electroplating solution. Place the electroplating solution in the electroplating tank, maintain the temperature at 70°C, and the pH value at 8.5.

[0042] Step (2): After the perforated liner pipe is degreased and activated with dilute hydrochloric acid, it is placed in a vacuum plasma cleaning device, argon gas is introduced, and it is treated at a power of 1000W for 15 minutes.

[0043] Step (3): The perforated liner pipe obtained in step (2) is used as the cathode, and a nickel-shaped anode that matches the inner wall profile is immersed in the electroplating solution. A pulse power source is used, with a current density of 8 ASD, a frequency of 1000 Hz, and a duty cycle of 30%. Mechanical stirring is performed at a rate of 200 r / min, and the electroplating time is 120 minutes.

[0044] Step (4): After electroplating is completed, the workpiece is removed, rinsed with deionized water, and dried in a 100°C air-drying oven for 30 minutes.

[0045] After the tungsten alloy plating layer is tested for Vickers hardness, neutral salt spray test, micro-morphology, and average plating layer thickness, the Vickers hardness is measured to be 1100HV1, the red rust time in the neutral salt spray test is 900 hours, the micro-morphology is dense and defect-free, the average thickness of the inner wall plating layer is 88μm, the average thickness of the plating layer at the hole is 80μm, and the ratio of the thickness at the hole to the average thickness of the inner wall plating layer is 0.91, as shown in Figure 1 , the microstructure is dense and free of defects such as holes, cracks, and slag inclusions.

[0046] Example 2

[0047] A tungsten alloy plated perforated liner pipe is prepared by the following steps:

[0048] Step (1): Prepare the raw materials of the electroplating solution by mass fraction: 80 parts of nickel sulfamate, 70 parts of sodium tungstate, 60 parts of complexing agent, 10 parts of conductive salt, 10 parts of buffer, 0.5 parts of stress reliever, 0.1 part of brightener, 0.1 part of surfactant, 0.5 part of rare earth salt, and 1000 parts of deionized water, wherein the complexing agent is composed of citrate and ethylenediaminetetraacetic acid in a mass ratio of 4:1, and the rare earth salt is cerium nitrate;

[0049] Prepare the electroplating solution according to the proportion, pre-mix the rare earth salt and 1 / 2 of the complexing agent into deionized water, completely dissolve, then add the remaining components, fully dissolve, stir uniformly and filter to obtain the electroplating solution. Place the electroplating solution in the electroplating tank, and maintain the temperature at 70°C and the pH value at 8.5;

[0050] Step (2): After the perforated liner pipe is degreased and activated with dilute hydrochloric acid, it is placed in a vacuum plasma cleaning device, argon is introduced, and it is treated at a power of 1000W for 15 minutes;

[0051] Step (3): The perforated liner pipe obtained in step (2) is used as the cathode, and a nickel-shaped anode that matches the inner wall profile is immersed in the electroplating solution. A pulse power source is used, the current density is set to 8 ASD, the frequency is 1000 Hz, the duty cycle is 30%, mechanical stirring is performed at a speed of 200 r / min, and the electroplating time is 120 minutes;

[0052] Step (4): After electroplating is completed, the workpiece is taken out, rinsed with deionized water, and dried in a 100°C air drying oven for 30 minutes.

[0053] After the tungsten alloy plated layer is tested for Vickers hardness, neutral salt spray test, micro-morphology, and average thickness of the plated layer, the Vickers hardness is measured to be 1000HV1, the red rust time of the neutral salt spray test is 850 hours, the micro-morphology is dense and defect-free, the average thickness of the inner wall plated layer is 70μm, the average thickness of the plated layer at the perforation is 65μm, and the ratio of the thickness at the perforation to the average thickness of the inner wall plated layer is 0.93.

[0054] Example 3

[0055] A tungsten alloy plated perforated liner pipe is prepared by the following steps:

[0056] Step (1): Prepare the raw materials of the electroplating solution by mass fraction:

[0057] Nickel sulfamate 120 parts, sodium tungstate 100 parts, complexing agent 100 parts, conductive salt 30 parts, buffer 20 parts, stress reliever 3 parts, brightener 1 part, surfactant 0.5 part, rare earth salt 5 parts, deionized water 1000 parts, wherein the complexing agent is citrate and ethylenediaminetetraacetic acid in a mass ratio of 4:1, and the rare earth salt is cerium nitrate;

[0058] The plating solution was prepared according to the ratio, the rare earth salt and 1 / 2 of the complexing agent were premixed and added to deionized water, and after complete dissolution, the remaining components were added, and after complete dissolution, the solution was stirred uniformly and filtered to obtain the plating solution. The plating solution was placed in the plating tank, and the temperature was maintained at 70℃, and the pH value was 8.5;

[0059] Step (2): After the perforated liner pipe was deoiled and activated with dilute hydrochloric acid, it was placed in a vacuum plasma cleaning device, argon was introduced, and it was treated at a power of 1000W for 15 minutes.

[0060] Step (3): The perforated liner pipe obtained in step (2) was used as a cathode, and a nickel-shaped anode matching the inner wall profile was immersed in the plating solution. A pulse power source was used, the current density was set to 8 ASD, the frequency was 1000 Hz, the duty cycle was 30%, and mechanical stirring was performed at a speed of 200 r / min. The plating time was 120 min.

[0061] Step (4): After plating was completed, the workpiece was removed, rinsed with deionized water, and dried in a 100℃ air drying oven for 30 min.

[0062] After the tungsten alloy coating was tested for Vickers hardness, neutral salt spray test, micro-morphology, and average coating thickness, the Vickers hardness was measured to be 1200HV1, the red rust time of the neutral salt spray test was 950h, the micro-morphology was dense and defect-free, the average thickness of the inner wall coating was 80μm, the average thickness of the coating at the hole was 75μm, and the ratio of the thickness at the hole to the average thickness of the inner wall coating was 0.94.

[0063] Comparative Example 1

[0064] The difference from Example 1 is only that the composition of the plating solution is: nickel sulfamate 70 parts, sodium tungstate 60 parts, complexing agent 50 parts, conductive salt 5 parts, buffer 5 parts, stress reliever 0.1 part, brightener 0.05 part, surfactant 0.05 part, rare earth salt 0.1 part, deionized water 1000 parts.

[0065] After the tungsten alloy coating is tested by Vickers hardness, neutral salt spray test, micro-morphology and average thickness of the coating, the Vickers hardness is 650HV1, the time of red rust appearing in the neutral salt spray test is 600h, the micro-morphology is compact without defects, the average thickness of the coating on the inner wall is 35μm, the average thickness of the coating at the hole is 28μm, and the ratio of the thickness at the hole to the average thickness of the coating on the inner wall is 0.8.

[0066] Comparative Example 2

[0067] The difference from Example 1 is that the composition of the electroplating solution is: nickel sulfamate 150 parts, sodium tungstate 120 parts, composite complexing agent 120 parts, conductive salt 50 parts, buffer 30 parts, stress reliever 5 parts, brightener 2 parts, surfactant 1 part, rare earth salt 10 parts, and deionized water 1000 parts.

[0068] After the tungsten alloy coating is tested by Vickers hardness, neutral salt spray test, micro-morphology and average thickness of the coating, the Vickers hardness is 750HV1, the time of red rust appearing in the neutral salt spray test is 650h, the micro-morphology is compact without defects, the average thickness of the coating on the inner wall is 40μm, the average thickness of the coating at the hole is 30μm, and the ratio of the thickness at the hole to the average thickness of the coating on the inner wall is 0.75.

[0069] Comparative Example 3

[0070] The difference from Example 1 is that the complexing agent only uses citrate.

[0071] After the tungsten alloy coating is tested by Vickers hardness, neutral salt spray test, micro-morphology and average thickness of the coating, the Vickers hardness is 650HV1, the time of red rust appearing in the neutral salt spray test is 500h, the micro-morphology can be seen to have defects such as holes and slag, the average thickness of the coating on the inner wall is 32μm, the average thickness of the coating at the hole is 25μm, the ratio of the thickness at the hole to the average thickness of the coating on the inner wall is 0.78, and Figure 2 , there are more defects in the figure, the ones in the frame are slag, and the ones marked by arrows are holes.

[0072] Comparative Example 4

[0073] The difference from Example 1 is that the rare earth salt is not added.

[0074] After the tungsten alloy coating is tested by Vickers hardness, neutral salt spray test, micro-morphology and average thickness of the coating, the Vickers hardness is 620HV1, the time of red rust appearing in the neutral salt spray test is 510h, the micro-morphology can be seen to have defects such as holes and slag, the average thickness of the coating on the inner wall is 30μm, the average thickness of the coating at the hole is 20μm, the ratio of the thickness at the hole to the average thickness of the coating on the inner wall is 0.67, and Figure 3, there are more defects in the figure, the frame is slag, the arrow mark is a hole.

[0075] Comparative Example 5

[0076] The difference from Example 1 is that the nickel sulfamate is replaced by nickel chloride.

[0077] After the Vickers hardness, neutral salt spray test, micro-morphology and average thickness of the coating test, the Vickers hardness is 800HV1, the neutral salt spray test appears red rust time is 300h, the micro-morphology is dense without defects, the average thickness of the inner wall coating is 45μm, the average thickness of the coating at the hole is 36μm, the ratio of the thickness at the hole to the average thickness of the inner wall coating is 0.8.

[0078] Comparative Example 6

[0079] The difference from Example 1 is that the hole lined tube is directly put into the electroplating tank after oil removal and dilute hydrochloric acid activation.

[0080] After the Vickers hardness, neutral salt spray test, micro-morphology and average thickness of the coating test, the Vickers hardness is 720HV1, the neutral salt spray test appears red rust time is 500h, the micro-morphology can be seen defects such as holes and slag, the average thickness of the inner wall coating is 38μm, the average thickness of the coating at the hole is 30μm, the ratio of the thickness at the hole to the average thickness of the inner wall coating is 0.79.

[0081] Comparative Example 7

[0082] The difference from Example 1 is that the conventional direct current power supply is used during electroplating, and the current density is 8ASD.

[0083] After the Vickers hardness, neutral salt spray test, micro-morphology and average thickness of the coating test, the Vickers hardness is 700HV1, the neutral salt spray test appears red rust time is 550h, the micro-morphology is dense without defects, the average thickness of the inner wall coating is 38μm, the average thickness of the coating at the hole is 30μm, the ratio of the thickness at the hole to the average thickness of the inner wall coating is 0.79.

[0084] Comparative Example 8

[0085] The difference from Example 1 is that only pulse power is used during electroplating, and no profiling anode is used.

[0086] After the Vickers hardness, neutral salt spray test, micro-morphology and average thickness of the coating were tested, the Vickers hardness was 650HV1, the time of red rust appearing in the neutral salt spray test was 500h, the micro-morphology had defects such as holes and slag, the average thickness of the coating on the inner wall was 35μm, the average thickness of the coating at the hole was 26μm, and the ratio of the thickness at the hole to the average thickness of the coating on the inner wall was 0.74.

[0087] Comparative Example 9

[0088] The difference from Example 1 is that a conventional direct current power supply is used during electroplating, the current density is 8A / cm2, and the pulse mode and the profiling anode are not used.

[0089] After the Vickers hardness, neutral salt spray test, micro-morphology and average thickness of the coating were tested, the Vickers hardness was 550HV1, the time of red rust appearing in the neutral salt spray test was 450h, the micro-morphology had defects such as holes and slag, the average thickness of the coating on the inner wall was 32μm, the average thickness of the coating at the hole was 20μm, and the ratio of the thickness at the hole to the average thickness of the coating on the inner wall was 0.63.

[0090] Comparative Example 10

[0091] The difference from Example 1 is that the pH value of the electroplating solution is 7.0.

[0092] After the Vickers hardness, neutral salt spray test, micro-morphology and average thickness of the coating were tested, the Vickers hardness was 450HV1, the time of red rust appearing in the neutral salt spray test was 400h, the micro-morphology was compact and had no defects, the average thickness of the coating on the inner wall was 25μm, the average thickness of the coating at the hole was 20μm, and the ratio of the thickness at the hole to the average thickness of the coating on the inner wall was 0.8.

[0093] Comparative Example 11

[0094] The difference from Example 1 is that the power of the plasma cleaning is 2000W, and the treatment time is 30min.

[0095] After the Vickers hardness, neutral salt spray test, micro-morphology and average thickness of the coating were tested, the Vickers hardness was 680HV1, the time of red rust appearing in the neutral salt spray test was 520h, the micro-morphology had defects such as holes and slag, the average thickness of the coating on the inner wall was 36μm, the average thickness of the coating at the hole was 30μm, and the ratio of the thickness at the hole to the average thickness of the coating on the inner wall was 0.83.

[0096] The Vickers hardness was detected according to GB / T 4340.1-2024 “Metallic Materials-Vickers Hardness Test-Part 1: Test Method”, and a load of 9.807N was used;

[0097] Microstructure detection: in accordance with GB / T 13298-2015 "Metal Microstructure Test Method";

[0098] Average thickness of plating layer detection: in accordance with GB / T 6462-2005 "Metal and Oxide Coating Thickness Measurement Microscope Method", the specific operation is as follows:

[0099] Sample preparation: sample from the plating layer of each example / contrast example, size 5mmx5mmx10mm, after inlaying and 400#-2000# sandpaper step-by-step polishing, ready for use.

[0100] The performance data of examples and contrast examples are shown in Table 1.

[0101] Table 1 Performance data of examples and contrast examples

[0102]

[0103] Embodiments 1~3 can establish a stable multi-coordination site environment by component ratio design, accurately control the codeposition of nickel and tungsten ions at the molecular scale, and deliberately avoid the introduction of chloride ions to fundamentally eliminate the source of late-stage pitting induction, thereby significantly improving the long-term stability of the plating layer in a corrosive environment. Rare earth salts can selectively adsorb at the growth interface due to their unique electronic layer structure, effectively reducing the deposition overpotential of tungsten to promote codeposition, and achieving grain refinement and structure densification. Plasma cleaning achieves interface purification and lattice activation at the atomic scale, providing a guarantee for obtaining a weak-interface-free metallurgical-grade bond. The synergistic effect of the profiled anode and the pulse current breaks through the edge effect of complex structures from the field dimension, and the pulse current promotes nucleation and ion replenishment during the relaxation period through transient high-energy input, thereby achieving thickness uniformity in the deep-hole region.The components of Comparative Example 1 are too low to form a thick and correct composition of the reinforcing phase; the components of Comparative Example 2 are too high, resulting in an imbalance of the electroplating solution, which produces a large amount of precipitate, thereby destroying the compactness and adhesion of the plating layer; the complexing agent of Comparative Example 3 only uses citrate, and the single citrate has insufficient complexing capacity, which cannot stabilize high concentrations of tungsten, resulting in low co-deposition efficiency, insufficient tungsten content in the plating layer, low hardness of the plating layer, and unstable electroplating solution, which leads to the generation of holes and slag inclusions; Comparative Example 4 does not add rare earth salt, and the lack of rare earth salt causes the co-deposition process to lose catalysis, resulting in difficult tungsten deposition, poor plating layer growth, coarse grains, low hardness, poor corrosion resistance, and insufficient compactness; Comparative Example 5 replaces the nickel sulfamate with nickel chloride, and the use of nickel chloride introduces chloride ions, although the hardness and thickness are acceptable, the neutral salt spray test time drops from 900 hours to 300 hours, and the chloride ions are wrapped in the plating layer, becoming a corrosion trigger point, which will quickly cause pitting corrosion once the corrosion medium reaches it; Comparative Example 6 directly places the perforated liner tube into the electroplating tank after oil removal and activation in dilute hydrochloric acid without plasma cleaning, and there are invisible contaminants and weak interface layers on the surface of the substrate, which leads to poor adhesion of the plating layer, easy failure from the interface under deposition stress or corrosion environment, and preferential corrosion from the weakly bonded area, which significantly reduces corrosion resistance; Comparative Example 7 uses a traditional direct current power supply during electroplating, with a current density of 8 ASD, and the direct current electroplating has persistent concentration polarization, resulting in high internal stress, low hardness, and poor compactness of the plating layer; Comparative Example 8 uses a pulse power supply during electroplating without using a profiled anode, which cannot solve the edge effect of the inner wall and hole of the perforated liner tube, and the electric lines cannot be uniformly distributed, which directly leads to serious thickness unevenness of the inner wall and hole edge, and cannot form effective full-area protection; Comparative Example 9 uses a traditional direct current power supply during electroplating with a current density of 8 ASD without using a pulse mode and a profiled anode, and the direct current electroplating has persistent concentration polarization, resulting in low hardness and poor compactness of the plating layer, and without using a profiled anode, the edge effect of the inner wall and hole of the perforated liner tube cannot be solved, which directly leads to serious thickness unevenness of the inner wall and hole edge; Comparative Example 10 has a pH value of 7.0 for the electroplating solution, which deviates from the optimal range of the complexing agent, especially the optimal working pH value of ethylenediaminetetraacetic acid, resulting in a decrease in complexing capacity, unstable electroplating solution, and out-of-control co-deposition process, which causes all performance indicators to decrease significantly; Comparative Example 11 has a power of 2000W for the plasma cleaning, and a processing time of 30 minutes, and too high power and too long processing time can lead to over-cleaning of the liner tube, which damages the surface of the liner tube and forms new defects, thereby reducing the adhesion and plating layer quality.

[0104] The above description is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes within the technical range disclosed by the present application according to the technical solution and inventive concept of the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for producing a tungsten alloy plating layer, characterized by, The method comprises the following steps: Step (1): preparing plating solution raw materials by mass fraction: 80-120 parts of nickel sulfamate, 70-100 parts of sodium tungstate, 60-100 parts of complexing agent, 10-30 parts of conductive salt, 10-20 parts of buffer, 0.5-3 parts of stress reliever, 0.1-1 part of brightener, 0.1-0.5 part of surfactant, 0.5-5 parts of rare earth salt, and 1000 parts of deionized water; The rare earth salt is premixed with 1 / 3-1 / 2 of the complexing agent and added to the deionized water, and after complete dissolution, the remaining components are added, and after complete dissolution, the mixture is stirred uniformly and filtered to obtain the plating solution, which is placed in a plating tank, and the temperature is maintained at 60-70 DEG C, and the pH value is 8.0-9.0; The complexing agent is a system composed of citrate and ethylenediaminetetraacetic acid in a mass ratio of 3-5:1; Step (2): after oil removal and acid activation of the perforated liner, the perforated liner is cleaned by argon plasma bombardment in a vacuum environment, the power is 800-1500 W, and the treatment time is 10-20 min; Step (3): the perforated liner obtained in step (2) is placed as a cathode in the plating tank, a profiled anode matching the profile of the substrate is used, and plating is carried out under pulsed current and mechanical stirring; Step (4): after plating is completed, the workpiece is taken out, washed with deionized water, and then placed in a forced air drying oven, dried at 80-120 DEG C for 20-40 min using circulating hot air.

2. The method of claim 1, wherein the tungsten alloy plating layer is formed by electroplating. In step (1), the conductive salt is nickel sulfate, the buffer is boric acid, the stress reliever is sodium saccharin, the brightener is propargyl alcohol, and the surfactant is sodium dodecyl sulfate.

3. The method of claim 1, wherein the tungsten alloy plating layer is formed by a process comprising: In step (1), the rare earth salt is cerium nitrate.

4. The method of claim 1, wherein the tungsten alloy coating is prepared by a process comprising: In step (3), the profiled anode is a nickel plate, the pulsed current density is 6-12 ASD, the pulse frequency is 500-1500 Hz, the duty cycle is 25%-35%, the plating time is 90-150 min, and the stirring rate is 150-250 r / min.

5. A tungsten alloy coating characterized by, The tungsten alloy plating layer is prepared by the method of any one of claims 1-4, is a tungsten-nickel alloy plating layer, has a thickness of 40-100 μm, and has a Vickers hardness of not less than 900 HV1.

6. A fenestrated liner tube comprising a tube body and a plurality of eyelets disposed on the tube body, wherein, The inner wall, outer wall and inner surface of all the holes of the pipe body are covered with the tungsten alloy plating layer as described in claim 5.

7. The fenestrated conduit of claim 6, wherein, The ratio of the thickness of the tungsten alloy plating layer at the holes to the average thickness of the inner wall of the pipe body is 0.85-1.05.

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