Electroplated nickel-titanium material as well as preparation method and application thereof
By using carburizing treatment and a specific nickel plating solution, the problem of poor bonding strength and wear resistance caused by oxidation during the nickel plating process of titanium materials was solved, thus improving the performance of titanium materials in conductive components and reliable welding applications.
Patent Information
- Application Number
- CN202610048309.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-14
- Publication Date
- 2026-02-10
AI Technical Summary
Titanium is prone to oxidation during nickel electroplating, resulting in poor coating bonding strength and wear resistance, which affects its application in conductive components and reliable welding.
By carburizing titanium materials to form a TiC strengthening phase, and using a nickel plating solution containing nickel sulfate, nickel chloride and sodium hypophosphite, the surface roughness and coating density of the titanium materials are improved. High-temperature heat treatment is then performed to enhance the bonding strength and wear resistance.
It improves the bonding strength between titanium and nickel plating, enhances the hardness and wear resistance of the plating, solves the oxidation problem of titanium during electroplating, and improves its application in aerospace, medical devices and chemical equipment.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of metal electroplating technology, and in particular to an electroplated nickel-titanium material, its preparation method, and its application. Background Technology
[0002] Because titanium has a density of only 4.51 g / cm³, about 60% that of steel, yet its strength is comparable to high-strength steel, titanium-based materials offer significant lightweighting benefits. This allows for substantial reductions in equipment weight, making them particularly suitable for weight-sensitive applications. Therefore, titanium components, with their low density, high strength, excellent corrosion resistance, and biocompatibility, are widely used in aerospace, chemical, medical device, and chemical equipment industries.
[0003] Due to its high chemical reactivity, titanium readily forms a dense and stable oxide film on its surface. This oxide film is an excellent insulator, resulting in extremely poor conductivity in titanium, making it unsuitable for direct use in components requiring conductivity. Furthermore, titanium is prone to oxidation during welding, making welding with other metals difficult. Electroplating a nickel layer is necessary as a transition layer to improve conductivity and enable reliable welding with other metals.
[0004] However, during the nickel plating process of titanium, the activated titanium comes into frequent contact with oxygen before electroplating, which aggravates surface oxidation and affects the deposition and bonding strength of the coating. The coating is prone to peeling and flaking. Moreover, the coating formed after electroplating has insufficient density, resulting in poor wear resistance and limiting the application fields of titanium. Summary of the Invention
[0005] This invention provides an electroplated nickel-plated titanium material, its preparation method, and its application. By pre-carburizing the titanium material, C atoms can diffuse in the titanium matrix and form a TiC reinforcing phase, which improves the hardness of the substrate and increases the surface roughness. This helps to improve the bonding strength between the titanium material and the nickel plating layer, thereby solving the problem that oxidation of the titanium material before nickel plating reduces the bonding strength and wear resistance of the plating layer, resulting in peeling and flaking.
[0006] To address the aforementioned technical problems, one objective of this invention is to provide a method for preparing electroplated nickel-titanium materials, comprising the following steps: (1) The titanium workpiece is degreased with a degreasing agent and then activated with pickling solution to obtain an activated workpiece; (2) The activated workpiece is transported to the gas carburizing equipment through the protective channel, and carburizing treatment is carried out in the gas carburizing equipment using an inert gas containing a carbon source to obtain a carburized workpiece. (3) The carburized workpiece is transported to the nickel plating equipment through the protective channel and nickel plating is performed using nickel plating solution to obtain a nickel-plated workpiece; (4) After washing and drying the nickel-plated workpiece, nickel-plated titanium material is obtained; In steps (2) and (3), the protective channel is filled with an inert gas atmosphere; In step (3), the nickel plating solution includes 220-270 g / L of nickel sulfate, 30-50 g / L of nickel chloride, 25-35 g / L of boric acid and the balance water.
[0007] The titanium material in this application is pre-treated to remove impurities and organic matter through degreasing, and the surface oxide film is decomposed by acid pickling. Because the titanium oxide film regenerates quickly, the process is carried out in an inert gas atmosphere after activation to isolate oxygen and slow down the oxidation rate of the titanium surface. Carburizing treatment allows carbon atoms to diffuse within the titanium material and form a TiC reinforcing phase, which not only enhances the hardness of the titanium substrate but also results in a high carbon concentration on the titanium surface. TiC nucleates and grows on the titanium surface in the form of particles or whiskers, increasing the surface roughness. Simultaneously, the addition of nickel sulfate and nickel chloride, along with boric acid buffer, to the nickel plating solution increases the density of the coating deposition, reducing porosity and defects. The combination of a rough interface and a highly dense coating improves the bonding strength between the titanium material and the nickel plating layer. Furthermore, this rough interface, formed by TiC hard ceramic, makes the electroplated layer less prone to peeling and more wear-resistant compared to mechanically polished titanium surfaces.
[0008] In some embodiments, in steps (2) and (3), the pressure of the inert gas in the protection channel is 0.10-0.15 MPa.
[0009] In some embodiments, in step (3), the nickel plating solution further includes 15-25 g / L of sodium hypophosphite.
[0010] This application also adds sodium hypophosphite to the nickel plating solution. Sodium hypophosphite can reduce nickel ions in the nickel solution to metallic nickel ions and deposit them on the surface of the titanium material, further improving the density of the coating. In addition, some hypophosphite ions will be reduced to generate phosphorus atoms and deposited in the coating to form a Ni-P alloy, thereby improving the hardness and wear resistance of the coating.
[0011] In some embodiments, in step (3), the nickel plating solution further includes 1-3 mL / L of brightener.
[0012] In some embodiments, in step (3), the brightener is sodium vinyl sulfonate.
[0013] In some embodiments, in step (4), the nickel-plated workpiece is washed and dried, and then heat-treated at a temperature of 300-500 ℃ for 1-3 h to obtain nickel-plated titanium material.
[0014] This application involves subjecting nickel-plated workpieces to high-temperature heat treatment. Under high-temperature conditions, the amorphous structure of the Ni-P alloy will crystallize, precipitating a dispersed phosphide hard phase, which effectively improves the hardness and wear resistance of the coating. At the same time, high-temperature heat treatment can also release the internal stress generated by atomic accumulation, promote the interdiffusion of atoms between the coating and the substrate, form a stronger metallurgical bond, and improve the coating's resistance to peeling.
[0015] In some embodiments, in step (3), the mass ratio of nickel sulfate to nickel chloride in the nickel plating solution is 25:(3-5).
[0016] This application controls the simultaneous addition of two nickel sources, nickel sulfate and nickel chloride, to the nickel plating solution. Nickel sulfate ensures the basic material basis for the plating layer, while nickel chloride ensures the stability of the electroplating process. Controlling the ratio of the two within the above-mentioned preferred range can further improve the density and wear resistance of the plating layer.
[0017] In some embodiments, in step (1), the pickling solution comprises 2%-4% hydrofluoric acid, 6%-10% auxiliary acid and the balance water, wherein the auxiliary acid is at least one of sulfuric acid, hydrochloric acid and nitric acid.
[0018] In some embodiments, in step (1), the auxiliary acid in the pickling solution is nitric acid.
[0019] In some embodiments, in step (1), the degreasing agent comprises 45-55 g / L of sodium hydroxide, 25-35 g / L of sodium carbonate, 4-6 g / L of surfactant and the balance being water.
[0020] In some embodiments, in step (1), the surfactant is cocoyl diethanolamide.
[0021] In some embodiments, in step (1), the degreasing treatment is performed at a temperature of 50-60 °C for 5-10 min.
[0022] In some implementations, the activation treatment time in step (1) is 4-6 min.
[0023] In some embodiments, in step (2), the mass fraction of carbon source in the carbon source-containing inert gas is 1%-3%.
[0024] In some embodiments, in step (2), the carburizing temperature is 900-1000 °C and the time is 1-3 h.
[0025] In some embodiments, the carbon source in step (2) is methane.
[0026] In some embodiments, in step (3), the nickel plating temperature is 25-35 °C and the current density is 10-15 A / dm². 2 The nickel plating time is 10-15 minutes.
[0027] In some embodiments, in step (4), the water washing is performed at a temperature of 30-50 °C for 3-10 min.
[0028] In some embodiments, in step (4), drying is performed at a temperature of 60-100 °C.
[0029] In some embodiments, in step (1), the purity of the titanium workpiece is ≥99%.
[0030] In some embodiments, the inert gases in the protective channel and the gas carburizing equipment are independent and include at least one of argon, neon, and nitrogen.
[0031] To solve the above-mentioned technical problems, the second objective of this invention is to provide an electroplated nickel-titanium material prepared by the aforementioned method.
[0032] To address the aforementioned technical problems, a third objective of this invention is to provide an application of electroplated nickel-titanium materials in aerospace, medical device, or chemical equipment materials.
[0033] Compared with the prior art, the present invention has the following beneficial effects: 1. The titanium material of this application is pre-treated by degreasing to remove impurities and organic matter, and then acid-washed to decompose the oxide film on the surface. Since the oxide film of titanium material regenerates quickly, the activated titanium material is processed in an inert gas atmosphere to isolate oxygen and slow down the oxidation rate of the titanium material surface. This can improve the bonding strength between the subsequent coating and the titanium material and improve the wear resistance of the titanium material.
[0034] 2. This application performs carburizing treatment on activated titanium material to form a TiC reinforcing phase in the titanium material to enhance hardness. TiC will nucleate and grow on the surface of the titanium material in the form of particles or whiskers, increasing the surface roughness of the titanium material. At the same time, nickel sulfate and nickel chloride are added to the nickel plating solution to achieve uniform deposition of the coating and increase the density. Overall, the bonding strength between the titanium material and the nickel coating is improved, and peeling is avoided.
[0035] 3. This application adds sodium hypophosphite to the nickel plating solution to further improve the density of the nickel layer. Some hypophosphite ions are reduced to generate phosphorus atoms and deposited in the coating to form a Ni-P alloy. During the heat treatment process, the amorphous structure of the Ni-P alloy will crystallize, precipitating a dispersed phosphide hard phase, which effectively improves the hardness and wear resistance of the coating, and promotes the interdiffusion of atoms between the coating and the substrate, forming a stronger metallurgical bond and improving the coating's resistance to peeling. Detailed Implementation
[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0037] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0038] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.
[0039] Example 1 A method for preparing an electroplated nickel-titanium material includes the following steps: (1) Add the titanium workpiece (purity ≥ 99.5%) to a stainless steel degreasing tank containing degreasing agent, and simultaneously use an ultrasonic generator for ultrasonic-assisted treatment. The degreasing agent includes NaOH with a concentration of 50 g / L, Na2CO3 with a concentration of 30 g / L, a surfactant with a concentration of 5 g / L, and the remainder is water. The surfactant is cocoyl diethanolamide. The treatment temperature is 55 ℃ and the treatment time is 8 min to obtain the degreased workpiece. (2) The degreased workpiece is transferred to the polytetrafluoroethylene pickling tank through a sealed channel and activated by pickling solution for 4 min. The pickling solution includes 3% HF and 8% HNO3 by mass and the remainder water, which can remove the oxide film on the surface of the workpiece and obtain the activated workpiece. (3) The activated workpiece is transported to the gas carburizing furnace through the protective channel. The protective channel contains argon gas with a purity of ≥99.99% and an argon gas pressure of 0.12 MPa. A mixed gas containing 2% methane and argon gas by volume is introduced into the gas carburizing furnace. The furnace is kept at 950 ℃ for 2 h and then cooled with the furnace to obtain the carburized workpiece. (4) The carburized workpiece is transported to the titanium alloy nickel plating tank through a protective channel. The protective channel contains argon gas with a purity ≥99.99% and an argon gas pressure of 0.12 MPa. The titanium alloy nickel plating tank is equipped with a soluble nickel anode with a purity of 99.95%, and nickel plating is performed using a nickel plating solution at a plating temperature of 30 ℃ and a current density of 12 A / dm³. 2 The nickel plating time is 15 min. The nickel plating solution includes nickel sulfate with a concentration of 250 g / L, nickel chloride with a concentration of 40 g / L, boric acid with a concentration of 30 g / L, sodium hypophosphite with a concentration of 20 g / L, brightener with a concentration of 2 mL / L, and the balance is water. The brightener is sodium vinyl sulfonate. The nickel-plated workpiece is obtained. (5) The nickel-plated workpiece was then washed with water at 40 °C for 5 min, dried at 80 °C, and then heat-treated at 400 °C for 2 h to obtain nickel-plated titanium material.
[0040] Example 2 A method for preparing an electroplated nickel-titanium material includes the following steps: (1) Add the titanium workpiece (purity ≥ 99.5%) to a stainless steel degreasing tank containing degreasing agent, and simultaneously use an ultrasonic generator for ultrasonic-assisted treatment. The degreasing agent includes NaOH with a concentration of 45 g / L, Na2CO3 with a concentration of 35 g / L, a surfactant with a concentration of 4 g / L, and the remainder is water. The surfactant is cocoyl diethanolamide. The treatment temperature is 50 ℃ and the treatment time is 10 min to obtain the degreased workpiece. (2) The degreased workpiece is transferred to the polytetrafluoroethylene pickling tank through a sealed channel and treated with pickling solution for 5 min. The pickling solution includes 2% HF and 10% HNO3 by mass and the remainder water, which can remove the oxide film on the surface of the workpiece and obtain the activated workpiece. (3) The activated workpiece is transported to the gas carburizing furnace through the protective channel. The protective channel contains argon gas with a purity of ≥99.99% and an argon gas pressure of 0.12 MPa. A mixed gas containing 2% methane and argon gas by volume is introduced into the gas carburizing furnace. The furnace is kept at 950 ℃ for 2 h and then cooled with the furnace to obtain the carburized workpiece. (4) The carburized workpiece is transported to the titanium alloy nickel plating tank through a protective channel. The protective channel contains argon gas with a purity ≥ 99.99% and an argon gas pressure of 0.12 MPa. The titanium alloy nickel plating tank is equipped with a soluble nickel anode with a purity of 99.95%, and nickel plating is performed using a nickel plating solution at a temperature of 30 ℃ and a current density of 10 A / dm³. 2 The nickel plating time is 10 min. The nickel plating solution includes nickel sulfate with a concentration of 220 g / L, nickel chloride with a concentration of 35 g / L, boric acid with a concentration of 35 g / L, sodium hypophosphite with a concentration of 15 g / L, brightener with a concentration of 1 mL / L, and the balance is water. The brightener is sodium vinyl sulfonate. The nickel-plated workpiece is obtained. (5) The nickel-plated workpiece was then washed with water at 40 °C for 5 min, dried at 80 °C, and then heat-treated at 400 °C for 2 h to obtain nickel-plated titanium material.
[0041] Example 3 A method for preparing an electroplated nickel-titanium material includes the following steps: (1) Add the titanium workpiece (purity ≥ 99.5%) to a stainless steel degreasing tank containing a degreasing agent, and simultaneously use an ultrasonic generator for ultrasonic-assisted treatment. The degreasing agent includes NaOH with a concentration of 55 g / L, Na2CO3 with a concentration of 25 g / L, a surfactant with a concentration of 6 g / L, and the remainder is water. The surfactant is cocoyl diethanolamide. The treatment temperature is 60 ℃ and the treatment time is 5 min to obtain the degreased workpiece. (2) The degreased workpiece is transferred to the polytetrafluoroethylene pickling tank through a sealed channel and treated with pickling solution for 6 min. The pickling solution includes 4% HF and 6% HNO3 by mass and the remainder water, which can remove the oxide film on the surface of the workpiece and obtain the activated workpiece. (3) The activated workpiece is transported to the gas carburizing furnace through the protective channel. The protective channel contains argon gas with a purity of ≥99.99% and an argon gas pressure of 0.12 MPa. A mixed gas containing 2% methane and argon gas by volume is introduced into the gas carburizing furnace. The furnace is kept at 950 ℃ for 2 h and then cooled with the furnace to obtain the carburized workpiece. (4) The carburized workpiece is transported to the titanium alloy nickel plating tank through a protective channel. The protective channel contains argon gas with a purity of ≥99.99% and an argon gas pressure of 0.12 MPa. The titanium alloy nickel plating tank is equipped with a soluble nickel anode with a purity of 99.95%, and nickel plating is performed using a nickel plating solution. The nickel plating temperature is 30 ℃ and the current density is 15 A / dm³. 2The nickel plating time is 12 min. The nickel plating solution includes nickel sulfate with a concentration of 270 g / L, nickel chloride with a concentration of 45 g / L, boric acid with a concentration of 25 g / L, sodium hypophosphite with a concentration of 25 g / L, brightener with a concentration of 3 mL / L, and the balance is water. The brightener is sodium vinyl sulfonate. The nickel-plated workpiece is obtained. (5) The nickel-plated workpiece was then washed with water at 40 °C for 5 min, dried at 80 °C, and then heat-treated at 400 °C for 2 h to obtain nickel-plated titanium material.
[0042] Example 4 A method for preparing electroplated nickel-titanium material, wherein each step and the reagents, equipment and process parameters used in each step are the same as those in Example 1, except that in step (5), the nickel-plated workpiece is washed with water at 40 ℃ for 5 min and dried at 80 ℃ to obtain the nickel-titanium material.
[0043] Example 5 A method for preparing electroplated nickel-titanium material, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, except that in step (4), the nickel plating solution includes nickel sulfate with a concentration of 250 g / L, nickel chloride with a concentration of 40 g / L, boric acid with a concentration of 30 g / L, brightener with a concentration of 2 mL / L and the balance being water.
[0044] Example 6 A method for preparing electroplated nickel-titanium material, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, except that in step (4), the nickel plating solution includes nickel sulfate with a concentration of 250 g / L, nickel chloride with a concentration of 40 g / L, boric acid with a concentration of 30 g / L, brightener with a concentration of 2 mL / L and the remainder water; In step (5), the nickel-plated workpiece is washed with water at 40 ℃ for 5 min and dried at 80 ℃ to obtain nickel-plated titanium material.
[0045] Example 7 A method for preparing electroplated nickel-titanium material, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, except that in step (4), the concentration of nickel sulfate in the nickel plating solution is 260 g / L and the concentration of nickel chloride is 30 g / L.
[0046] Example 8 A method for preparing electroplated nickel-titanium material, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, except that in step (4), the concentration of nickel sulfate in the nickel plating solution is 240 g / L and the concentration of nickel chloride is 50 g / L.
[0047] Example 9 A method for preparing electroplated nickel-titanium materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, except that in step (2), the pickling solution includes 3% HF and 8% H2SO4 by mass and the balance being water.
[0048] Example 10 A method for preparing electroplated nickel-titanium material, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, except that in step (2), the pickling solution includes 3% HF and 8% HCl by mass and the remainder water.
[0049] Example 11 A method for preparing electroplated nickel-titanium materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, the difference being that in step (3), the activated workpiece is transported to the gas carburizing furnace through a protective channel, the protective channel contains argon gas with a purity ≥99.99% and an argon gas pressure of 0.12 MPa, and a mixed gas containing 1% methane and argon gas by volume is introduced into the gas carburizing furnace, and the temperature is maintained at 950 ℃ for 1 h, and the carburized workpiece is obtained by cooling with the furnace.
[0050] Example 12 A method for preparing electroplated nickel-titanium materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, the difference being that in step (3), the activated workpiece is transported to the gas carburizing furnace through a protective channel, the protective channel contains argon gas with a purity ≥99.99% and an argon gas pressure of 0.12 MPa, and a mixed gas containing 3% methane and argon gas by volume is introduced into the gas carburizing furnace, and the temperature is maintained at 950 ℃ for 3 h, and the carburized workpiece is obtained by cooling with the furnace.
[0051] Example 13 A method for preparing electroplated nickel-titanium materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, except that in step (4), the nickel plating solution includes nickel sulfate with a concentration of 250 g / L, nickel chloride with a concentration of 40 g / L, boric acid with a concentration of 30 g / L, sodium hypophosphite with a concentration of 20 g / L and the balance being water.
[0052] Comparative Example 1 A method for preparing an electroplated nickel-titanium material includes the following steps: (1) Add the titanium workpiece (purity ≥ 99.5%) to a stainless steel degreasing tank containing degreasing agent, and simultaneously use an ultrasonic generator for ultrasonic-assisted treatment. The degreasing agent includes NaOH with a concentration of 50 g / L, Na2CO3 with a concentration of 30 g / L, a surfactant with a concentration of 5 g / L, and the remainder is water. The surfactant is cocoyl diethanolamide. The treatment temperature is 55 ℃ and the treatment time is 8 min to obtain the degreased workpiece. (2) The degreased workpiece is transferred to the polytetrafluoroethylene pickling tank through a sealed channel and treated with pickling solution for 4 min. The pickling solution includes 3% HF and 8% HNO3 by mass and the remainder water, which can remove the oxide film on the surface of the workpiece and obtain the activated workpiece. (3) The activated workpiece is transported to the titanium alloy nickel plating tank through a protective channel. The protective channel contains argon gas with a purity ≥99.99% and an argon gas pressure of 0.12 MPa. The titanium alloy nickel plating tank is equipped with a soluble nickel anode with a purity of 99.95%, and nickel plating is performed using a nickel plating solution at a plating temperature of 30 ℃ and a current density of 12 A / dm³. 2 The nickel plating time is 15 min. The nickel plating solution includes nickel sulfate with a concentration of 250 g / L, nickel chloride with a concentration of 40 g / L, boric acid with a concentration of 30 g / L, sodium hypophosphite with a concentration of 20 g / L, brightener with a concentration of 2 mL / L, and the balance is water. The brightener is sodium vinyl sulfonate. The nickel-plated workpiece is obtained. (4) The nickel-plated workpiece was then washed with water at 40 ℃ for 5 min, dried at 80 ℃, and then heat-treated at 400 ℃ for 2 h to obtain nickel-plated titanium material.
[0053] Comparative Example 2 A method for preparing an electroplated nickel-titanium material includes the following steps: (1) Add the titanium workpiece (purity ≥ 99.5%) to a stainless steel degreasing tank containing degreasing agent, and simultaneously use an ultrasonic generator for ultrasonic-assisted treatment. The degreasing agent includes NaOH with a concentration of 50 g / L, Na2CO3 with a concentration of 30 g / L, a surfactant with a concentration of 5 g / L, and the remainder is water. The surfactant is cocoyl diethanolamide. The treatment temperature is 55 ℃ and the treatment time is 8 min to obtain the degreased workpiece. (2) The degreased workpiece is transferred to the polytetrafluoroethylene pickling tank through a sealed channel and treated with pickling solution for 4 min. The pickling solution includes 3% HF and 8% HNO3 by mass and the remainder water, which can remove the oxide film on the surface of the workpiece and obtain the activated workpiece. (3) The activated workpiece is transported to the titanium alloy nickel plating tank through a protective channel. The protective channel contains argon gas with a purity ≥99.99% and an argon gas pressure of 0.12 MPa. The titanium alloy nickel plating tank is equipped with a soluble nickel anode with a purity of 99.95%, and nickel plating is performed using a nickel plating solution at a plating temperature of 30 ℃ and a current density of 12 A / dm³. 2 The nickel plating time is 15 min. The nickel plating solution includes nickel sulfate with a concentration of 250 g / L, nickel chloride with a concentration of 40 g / L, boric acid with a concentration of 30 g / L, sodium hypophosphite with a concentration of 20 g / L, brightener with a concentration of 2 mL / L, and the balance is water. The brightener is sodium vinyl sulfonate. The nickel-plated workpiece is obtained. (4) The nickel-plated workpiece is then washed with water at 40 °C for 5 min and dried at 80 °C to obtain nickel-plated titanium material.
[0054] Comparative Example 3 A method for preparing electroplated nickel-titanium material, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, except that in step (4), the nickel plating solution includes nickel sulfate with a concentration of 290 g / L, boric acid with a concentration of 30 g / L, sodium hypophosphite with a concentration of 20 g / L, brightener with a concentration of 2 mL / L and the remainder being water.
[0055] Comparative Example 4 A method for preparing electroplated nickel-titanium materials, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, except that in step (4), the nickel plating solution includes nickel chloride with a concentration of 290 g / L, boric acid with a concentration of 30 g / L, sodium hypophosphite with a concentration of 20 g / L, brightener with a concentration of 2 mL / L and the balance being water.
[0056] Comparative Example 5 A method for preparing electroplated nickel-titanium material, wherein each step and the reagents, equipment and process parameters used in each step are the same as in Example 1, except that in step (3), the activated workpiece is transported to the carburizing furnace through a protective channel, and the protective channel is filled with atmospheric pressure air. In step (4), the carburized workpiece is transported to the titanium alloy nickel plating tank through a protective channel, which is filled with atmospheric pressure air.
[0057] Comparative Example 6 A method for preparing an electroplated nickel-titanium material includes the following steps: (1) Add the titanium workpiece (purity ≥ 99.5%) to a stainless steel degreasing tank containing degreasing agent, and simultaneously use an ultrasonic generator for ultrasonic-assisted treatment. The degreasing agent includes NaOH with a concentration of 50 g / L, Na2CO3 with a concentration of 30 g / L, a surfactant with a concentration of 5 g / L, and the remainder is water. The surfactant is cocoyl diethanolamide. The treatment temperature is 55 ℃ and the treatment time is 8 min to obtain the degreased workpiece. (2) The degreased workpiece is transported to a gas carburizing furnace. A mixed gas containing 2% methane and argon by volume is introduced into the gas carburizing furnace. The workpiece is kept at 950 °C for 2 h and then cooled in the furnace to obtain the carburized workpiece. (3) The carburized workpiece is transferred to the polytetrafluoroethylene pickling tank through a sealed channel and treated with pickling solution for 4 min. The pickling solution includes 3% HF and 8% HNO3 by mass and the remainder water, which can remove the oxide film on the surface of the workpiece and obtain the activated workpiece. (4) The activated workpiece is transported to the titanium alloy nickel plating tank through a protective channel. The protective channel contains argon gas with a purity ≥ 99.99% and an argon gas pressure of 0.12 MPa. The titanium alloy nickel plating tank is equipped with a soluble nickel anode with a purity of 99.95%, and nickel plating is performed using a nickel plating solution at a plating temperature of 30 ℃ and a current density of 12 A / dm³. 2 The nickel plating time is 15 min. The nickel plating solution includes nickel sulfate with a concentration of 250 g / L, nickel chloride with a concentration of 40 g / L, boric acid with a concentration of 30 g / L, sodium hypophosphite with a concentration of 20 g / L, brightener with a concentration of 2 mL / L, and the balance is water. The brightener is sodium vinyl sulfonate. The nickel-plated workpiece is obtained. (5) The nickel-plated workpiece was then washed with water at 40 °C for 5 min, dried at 80 °C, and then heat-treated at 400 °C for 2 h to obtain nickel-plated titanium material.
[0058] Performance testing 1. Hardness test: The nickel-plated titanium materials of the examples and comparative examples were subjected to Vickers hardness test with a load of 100g. The test results are shown in Table 2 below.
[0059] 2. Bond strength test: The bonding strength of the nickel-plated titanium materials in the examples and comparative examples were tested according to ISO2409 standard. A 1 mm x 10 mm cross-cut test was used. Small squares were cut horizontally and vertically. 3M 600 tape was used to stick the tape in the cross-cut. The 3M tape was quickly pulled up and the size of the peeling area of the small squares was observed. The evaluation level was evaluated according to the standard in Table 1. The evaluation results are shown in Table 2 below.
[0060] 3. Wear resistance test: The nickel-plated titanium materials of the examples and comparative examples were subjected to friction test using a friction testing machine. Alumina balls with a diameter of 5 mm were used as the friction pair. Under a load of 8 N, the balls were moved in a straight line reciprocating motion of 2.5 mm at a speed of 0.8 mm / s on the nickel-plated titanium material for 100 min. The wear rate (by mass) before and after the friction test was tested. The test results are shown in Table 2 below.
[0061] Table 1 - Evaluation Criteria for the Bond Strength between Coating and Titanium Material Table 2 - Performance test results of electroplated nickel-titanium materials in the embodiments and comparative examples of this application. As shown in Table 2, the titanium materials in Examples 1-3 of this application are activated and then operated in an inert gas atmosphere to slow down the oxidation rate of the titanium material surface. The TiC strengthening phase is formed in the titanium material through carburizing treatment, which can enhance the hardness of the titanium substrate. At the same time, TiC will nucleate and grow on the surface of the titanium material in the form of particles or whiskers, which can improve the surface roughness of the titanium material, enhance the bonding strength between the titanium material and the nickel plating, and improve the overall hardness.
[0062] Compared to Example 1, the titanium material in Comparative Example 1 was not pre-treated with a penetrant, resulting in reduced hardness of the titanium substrate and the absence of an uneven TiC hardened ceramic layer on the titanium surface. This led to weaker interfacial bonding between the titanium material and the coating, resulting in poor resistance to peeling and lower overall hardness. In Comparative Example 5, the titanium material underwent acid pickling and activation to remove the oxide film, but no inert gas was used to isolate oxygen. During transport, the titanium surface was prone to oxidation upon contact with oxygen, generating an uneven oxide film. This made it difficult for nickel ions to deposit during electroplating, easily causing peeling and flaking, and resulting in numerous coating defects and large grains, leading to poor wear resistance.
[0063] Example 1 of this application, by simultaneously adding nickel sulfate and nickel chloride as two nickel sources to the nickel plating solution and optimizing their ratio, and using boric acid as a pH buffer to maintain pH stability, effectively improved the density of the coating deposition and reduced defects such as porosity and pitting. In contrast, Comparative Example 3's nickel plating solution only added nickel sulfate, without nickel chloride, resulting in uneven coating deposition on the titanium surface and reduced density, thus affecting the bonding strength between the titanium and the coating. Comparative Example 4's nickel plating solution only added nickel chloride, without nickel sulfate, resulted in poor coating density and insufficient hardness on the titanium surface, leading to a significant reduction in its wear resistance.
[0064] Compared to Example 1, Comparative Example 6 subjected the degreased titanium material to carburizing treatment. The titanium material surface had a dense and highly adsorbent passivation oxide film, which affected the diffusion of carbon atoms in the titanium substrate. This resulted in very few TiC strengthening phases formed in the titanium material, leading to limited improvement in the hardness of the titanium material. Furthermore, fewer TiC particles were formed on the surface of the titanium material, resulting in lower surface roughness. In addition, some of the TiC particles may have dissolved in the pickling solution during the subsequent activation process, leading to a significant reduction in the bonding strength between the titanium material and the nickel plating layer and poor resistance to peeling.
[0065] The nickel plating solution in Example 1 of this application contains sodium hypophosphite, which not only increases the density of the nickel layer, but also reduces some hypophosphite ions to form phosphorus atoms, which are deposited in the coating to form a Ni-P alloy, thereby increasing the hardness of the coating. At the same time, during the subsequent heat treatment process, the amorphous structure of the Ni-P alloy will crystallize, precipitating a dispersed phosphide hard phase, further improving the hardness and wear resistance of the coating, and promoting the interdiffusion of atoms between the coating and the substrate to form a stronger metallurgical bond, thereby improving the coating's resistance to peeling.
[0066] Compared to Example 1, the titanium material in Example 4 was not heat-treated after nickel plating, resulting in a decrease in the hardness of the coating and a corresponding decrease in wear resistance. Furthermore, a metallurgical interface could not be formed between the titanium material and the coating, leading to a decrease in the bonding strength between them. In Example 5, the nickel plating solution did not contain sodium hypophosphite, which affected the density of the coating deposition during electroplating, impacting the interfacial bonding strength and reducing anti-peeling performance. Simultaneously, the absence of sodium hypophosphite prevented the formation of a Ni-P alloy in the coating, resulting in a slight decrease in coating hardness. Ultimately, the wear resistance of the nickel-plated titanium material decreased accordingly.
[0067] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.
Claims
1. A method for preparing an electroplated nickel-titanium material, characterized in that, Includes the following steps: (1) The titanium workpiece is degreased with a degreasing agent and then activated with pickling solution to obtain an activated workpiece; (2) The activated workpiece is transported to the gas carburizing equipment through the protective channel, and carburizing treatment is carried out in the gas carburizing equipment using an inert gas containing a carbon source to obtain a carburized workpiece. (3) The carburized workpiece is transported to the nickel plating equipment through the protective channel and nickel plating is performed using nickel plating solution to obtain a nickel-plated workpiece; (4) After washing and drying the nickel-plated workpiece, nickel-plated titanium material is obtained; In steps (2) and (3), the protective channel is filled with an inert gas atmosphere; In step (3), the nickel plating solution comprises 220-270 g / L of nickel sulfate, 30-50 g / L of nickel chloride, 25-35 g / L of boric acid, and the balance being water.
2. The method for preparing an electroplated nickel-titanium material as described in claim 1, characterized in that, In step (3), the nickel plating solution also includes 15-25 g / L of sodium hypophosphite; And / or, in step (3), the nickel plating solution further includes 1-3 mL / L of brightener.
3. The method for preparing an electroplated nickel-titanium material as described in claim 1, characterized in that, In step (4), the nickel-plated workpiece is washed and dried, and then heat-treated at a temperature of 300-500 ℃ for 1-3 h to obtain nickel-plated titanium material.
4. The method for preparing an electroplated nickel-titanium material as described in claim 1, characterized in that, In step (3), the mass ratio of nickel sulfate to nickel chloride in the nickel plating solution is 25:(3-5).
5. The method for preparing an electroplated nickel-titanium material as described in claim 1, characterized in that, In step (1), the pickling solution comprises 2%-4% hydrofluoric acid, 6%-10% auxiliary acid and the balance water, wherein the auxiliary acid is at least one of sulfuric acid, hydrochloric acid and nitric acid; And / or, in step (1), the degreasing agent comprises 45-55 g / L sodium hydroxide, 25-35 g / L sodium carbonate, 4-6 g / L surfactant and the balance water.
6. The method for preparing an electroplated nickel-titanium material as described in claim 1, characterized in that, In step (1), the degreasing treatment temperature is 50-60 ℃ and the time is 5-10 min; And / or, in step (1), the activation treatment time is 4-6 min.
7. The method for preparing an electroplated nickel-titanium material as described in claim 1, characterized in that, In step (2), the mass fraction of the carbon source in the carbon-containing inert gas is 1%-3%; And / or, in step (2), the carburizing treatment temperature is 900-1000 ℃ and the time is 1-3 h.
8. The method for preparing an electroplated nickel-titanium material as described in claim 1, characterized in that, In step (3), the nickel plating temperature is 25-35 ℃ and the current density is 10-15 A / dm. 2 The nickel plating time is 10-15 minutes.
9. An electroplated nickel-titanium material prepared by the method for preparing electroplated nickel-titanium material as described in any one of claims 1-8.
10. The application of the electroplated nickel-titanium material as described in claim 9 in aerospace, medical device, or chemical equipment materials.