A nanocrystalline Co-Ni alloy, a nanocrystalline Co-Ni alloy electroplating solution, and its application method

Abstract

This invention discloses a nanocrystalline Co-Ni alloy, characterized in that the nanocrystalline Co-Ni alloy comprises the chemical formula Co. x Ni 1‑x Where x is the atomic percentage, and 38 ≤ x ≤ 60. This invention also discloses a nanocrystalline Co-Ni alloy electroplating solution and a method for using the electroplating solution.

Description

Technical Field

[0001] This invention relates to a nanocrystalline Co-Ni alloy, which is, for example, particularly but not exclusively, a Ni-rich / Co-rich nanocrystalline Co-Ni alloy. It also relates to an electroplating solution for the nanocrystalline Co-Ni alloy and a method of using the electroplating solution. Background Technology

[0002] Nanocrystalline alloys refer to metallic alloy materials with grain sizes smaller than 100 nm. Due to their unique microstructure, they exhibit a series of superior mechanical, physical, and chemical properties. In terms of mechanical properties, the strength and hardness of nanocrystalline alloys are often several times higher than those of coarse-grained alloys of the same composition. In terms of physical properties, nanocrystalline alloys typically exhibit higher magnetic and electrochemical properties, offering significant advantages in electromagnetic applications and electrocatalysis. In terms of chemical properties, nanocrystalline alloys demonstrate excellent corrosion resistance. Therefore, nanocrystalline materials have been a subject of extensive research, and nanocrystalline alloys have broad application prospects in aerospace, automotive, energy, and electronics fields.

[0003] Inert gas condensation is an effective method for preparing nanocrystalline alloys, and it has been successfully used to prepare nanocrystalline alloys such as Cu, Pd, TiO2, and Fe-Sc / Si. However, samples prepared using this method cannot be guaranteed to be free from oxidation, and it also introduces many defects such as porosity and cracks. Especially during tensile testing, the presence of porosity and cracks reduces both strength and toughness. Large plastic deformation can obtain ultrafine and nanocrystalline materials with different grain sizes, but high-pressure torsion is limited by sample size and cannot prepare samples with a thickness exceeding 1 mm and a diameter greater than 20 mm. Furthermore, the large size and high maintenance cost of large plastic deformation equipment also limit its application. Nanocrystalline materials prepared by magnetron sputtering are mostly two-dimensional thin film samples, similarly limited by size.

[0004] Therefore, the present invention seeks to eliminate or at least mitigate such disadvantages by providing a new or otherwise improved nanocrystalline alloy. Summary of the Invention

[0005] In a first aspect of the present invention, a nanocrystalline Co-Ni alloy is provided, characterized in that the nanocrystalline Co-Ni alloy comprises the chemical formula Co. x Ni 1-x x is the atomic percentage, and 38 ≤ x ≤ 60.

[0006] Optionally, the nanocrystalline Co-Ni alloy has a single-phase face-centered cubic crystal structure.

[0007] Optionally, the average grain size of the nanocrystalline Co-Ni alloy is between 17 nm and 24 nm.

[0008] Optionally, the yield strength of the nanocrystalline Co-Ni alloy is from 1200 MPa to 1500 MPa.

[0009] Optionally, the tensile plasticity of the nanocrystalline Co-Ni alloy is 8% to 10%.

[0010] Optionally, the compressive strength of the nanocrystalline Co-Ni alloy is between 5500 MPa and 6000 MPa.

[0011] In an optional embodiment, the nanocrystalline Co-Ni alloy is a Ni-rich nanocrystalline Co-Ni alloy and has the chemical formula Co. 38 Ni 62 .

[0012] In an optional embodiment, the nanocrystalline Co-Ni alloy is a Co-rich nanocrystalline Co-Ni alloy and has the chemical formula Co. 60 Ni 40 .

[0013] Optionally, the yield strength of the Ni-rich nanocrystalline Co-Ni alloy is 1404.5 MPa.

[0014] Optionally, the yield strength of the Co-rich nanocrystalline Co-Ni alloy is 1276 MPa.

[0015] In a second aspect of the invention, a nanocrystalline Co-Ni alloy electroplating solution is provided, wherein the chemical formula of the nanocrystalline Co-Ni alloy is Co. x Ni 1-x Where x is the atomic percentage, 38≤x≤60, the characteristic is that the nanocrystalline Co-Ni alloy electroplating solution comprises: 85g·L -1 -100g·L -1 NiSO4·6H2O, 20g·L -1 -35g·L -1 CoSO4·7H2O, 45g·L - 1 NiCl2·6H2O, 20g·L -1 H3BO3 and 2g·L -1 saccharin.

[0016] In an optional embodiment, the pH value of the nanocrystalline Co-Ni alloy electroplating solution is 3.5-3.8.

[0017] In a third aspect of the present invention, a method for using the nanocrystalline Co-Ni alloy electroplating solution according to the second aspect of the present invention is provided, characterized in that the method comprises the following steps:

[0018] The electroplating solution was prepared according to the following composition: 85 g·L -1 -100g·L -1 NiSO4·6H2O, 20g·L -1 -35g·L -1 CoSO4·7H2O, 45g·L -1 NiCl2·6H2O, 20g·L -1 H3BO3 and 2g·L -1 saccharin;

[0019] Using a pretreated stainless steel plate as the cathode, a titanium plate as the anode, and a KCl saturated calomel electrode as the reference electrode, the cathode, the anode, and the reference electrode are placed in the electroplating solution.

[0020] Electrochemical deposition is performed by passing an electric current between the electrodes.

[0021] In an optional implementation, the current is a single-pulse square wave current with a pulse width of 0.5 ms and a current density of 120 mA cm⁻¹. -2 .

[0022] Optionally, the electrochemical deposition is carried out for at least 24 hours.

[0023] Optionally, the electrochemical deposition is performed at a temperature of 40°C to 50°C.

[0024] Optionally, the electroplating solution is stirred at a rate of 400 rpm to 600 rpm. Attached Figure Description

[0025] The invention will now be described more specifically by way of example only with reference to the accompanying drawings, in which:

[0026] Figure 1 A schematic diagram of a single-phase square wave pulse electrodeposition three-electrode system is shown.

[0027] Figure 2 The dimensional cutting drawing of the tensile sample is shown;

[0028] Figure 3A The image shows a scanning transmission electron microscope (STEM) image of an electrodeposited nickel-rich nanocrystalline cobalt-nickel (Co-Ni) alloy sample. The inset is a selected area electron diffraction pattern.

[0029] Figure 3B The grain size distribution of a nickel-rich nanocrystalline cobalt-nickel alloy sample is shown.

[0030] Figure 4 The tensile curves of nickel-rich nanocrystalline cobalt-nickel alloys are shown.

[0031] Figure 5 The tensile fracture morphology of a nickel-rich nanocrystalline cobalt-nickel alloy is shown in the left image and the enlarged view of the blue marked area of ​​the tensile fracture in the right image. The blue arrows represent dimples in the fracture surface.

[0032] Figure 6A Bright-field transmission electron microscopy (TEM) image of an electrodeposited cobalt-rich nanocrystalline cobalt-nickel alloy sample is shown. The inset is a selected area electron diffraction (SED) pattern.

[0033] Figure 6B The grain size distribution of a cobalt-rich nanocrystalline cobalt-nickel alloy sample is shown.

[0034] Figure 7 The tensile curves of a cobalt-rich nanocrystalline cobalt-nickel alloy are shown.

[0035] Figure 8 The image shows a tensile fracture morphology of a cobalt-rich nanocrystalline cobalt-nickel alloy (left) and an enlarged view of the orange marked area of ​​the tensile fracture (right). The orange arrows represent dimples in the fracture surface. Detailed Implementation

[0036] As used herein, unless the context clearly indicates otherwise, the forms “a” and “the” are intended to include both singular and plural forms.

[0037] The terms “example” or “exemplary” as used in this invention are intended to be used as examples, instances, or illustrations. Any aspect or design described as “exemplary” in this disclosure is not necessarily to be construed as being more preferred or advantageous than other aspects or designs. Rather, the use of the terms “example” or “exemplary” is intended to present concepts in a specific manner. As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless otherwise specified or the context clearly indicates, “X adopts A or B” is intended to mean any natural inclusive permutation. That is, “X adopts A or B” holds true if X adopts A; X adopts B; or X adopts both A and B.

[0038] How to make materials possess both strength and ductility has been a major challenge that materials scientists have long sought to overcome. According to the Hall-Page relation, nanocrystalline alloys have a large yield strength due to their small grain size, but this comes at the cost of sacrificing most of their ductility, and their elongation cannot compare with that of coarse-grained alloys of the same composition.

[0039] Without being bound by theoretical constraints, the inventors, through their own research, experiments, and trials, devised a method for preparing nanocrystalline alloys, particularly nanocrystalline cobalt-nickel (Co-Ni) alloys, using electrochemical deposition. It is believed that the preparation method of this invention has advantages such as simple equipment, easy operation, low cost, and the ability to produce samples without limitations on size or shape, as well as high sample purity and density. Furthermore, it is believed that nanocrystalline alloys with different properties can be prepared by adjusting parameters such as electrodeposition current density, deposition temperature, electroplating bath pH, ​​and deposition current waveform. For example, in some embodiments, compared to coarse-grained alloys of the same composition, the hardness of the nanocrystalline cobalt-nickel alloy of this invention can be increased by three times, and the tensile yield strength can be increased by ten times. In some embodiments, microstructure and mechanical property characterization shows that the nanocrystalline cobalt-nickel alloy of this invention possesses excellent mechanical properties, such as a yield strength as high as 1.2-1.5 GPa, tensile plasticity as high as 8%-10%, and compressive strength as high as 5.5-6 GPa.

[0040] In a first aspect of the present invention, a nanocrystalline Co-Ni alloy is provided, characterized in that the nanocrystalline Co-Ni alloy comprises the chemical formula Co. x Ni 1-x Where x is the atomic percentage, and 38 ≤ x ≤ 60. For example, nanocrystalline Co-Ni alloys can have the chemical formula Co. 38 Ni 62 Co 40 Ni 60 Co 41 Ni 59 Co 45 Ni 55 Co 50 Ni 50 Co 53 Ni 47 Co 60 Ni 40 The nanocrystalline Co-Ni alloy has a single-phase face-centered cubic crystal structure. In some embodiments, the average grain size of the nanocrystalline Co-Ni alloy is between 17 nm and 24 nm. It is believed that such a small grain size endows the nanocrystalline alloy with some unique structure and properties. In particular, in the nanocrystalline Co-Ni alloy, it is believed that due to the large grain boundary volume ratio, the grain boundary strengthening effect is significant, and therefore the alloy of the present invention exhibits excellent tensile properties. In some exemplary embodiments, the yield strength of the nanocrystalline Co-Ni alloy of the present invention can reach 1200 MPa to 1500 MPa, the tensile plasticity can reach 8% to 10%, and the compressive strength can reach 5500 MPa to 6000 MPa.

[0041] In some specific embodiments, the nanocrystalline Co-Ni alloy may be a Ni-rich nanocrystalline Co-Ni alloy. In this embodiment, the Ni-rich nanocrystalline Co-Ni alloy (also known as a nickel-rich nanocrystalline cobalt-nickel alloy) has the chemical formula Co. 38 Ni 62 It exhibits a yield strength of 1404.5 MPa. In some other specific embodiments, the nanocrystalline Co-Ni alloy may be a Co-rich nanocrystalline Co-Ni alloy. In this embodiment, the Ni-rich nanocrystalline Co-Ni alloy (also known as a cobalt-rich nanocrystalline cobalt-nickel alloy) has the chemical formula Co. 60 Ni 40 It has a yield strength of 1276 MPa.

[0042] In a second aspect of the invention, a nanocrystalline Co-Ni alloy electroplating solution is provided, particularly for the nanocrystalline Co-Ni alloy described herein. That is, a solution with the chemical formula Co... x Ni 1-x An electroplating solution for nanocrystalline Co-Ni alloys (x is atomic percentage, 38 ≤ x ≤ 60). Without being bound by theory, the inventors have devised an electroplating solution with the following components particularly suitable for preparing the nanocrystalline Co-Ni alloys described herein. Specifically, the electroplating solution may include: 85 g·L⁻¹ -1 -100g·L -1 Nickel sulfate hexahydrate (NiSO4·6H2O), 20 g·L -1 -35g·L -1 Cobalt sulfate heptahydrate (CoSO4·7H2O), 45 g·L -1 Nickel chloride hexahydrate (NiCl2·6H2O), 20 g·L -1 Boric acid (H3BO3) and 2 g·L -1 Saccharin (C7H5NO3S). Without being bound by theory, it is believed that each component may have a specific role in the preparation / electrochemical deposition of the nanocrystalline Co-Ni alloy described herein. Specifically, NiSO4·6H2O and CoSO4·7H2O can be used as Ni... 2+ and Co 2+ The main source; NiCl2·6H2O can be used as a secondary / additional Ni in this sulfate electroplating solution. 2+ Source; H3BO3 can have one or more of the following functions: oxygen evolution inhibitor, catalyst to promote Ni deposition and growth rate, pH buffer, hydrogen evolution inhibitor, surface passivating agent to reduce passivation film formation; saccharin can be used as an internal stress release agent in electrochemically deposited nanocrystalline Co-Ni alloys and to refine grains.

[0043] The electroplating solution of the present invention is preferably acidic. Without being bound by theory, it is believed that an acidic environment can promote the faster dissolution of newly deposited metal and inhibit the formation and adsorption of metal hydroxides. In some specific embodiments, the pH of the electroplating solution of the present invention can be 3.5-3.8.

[0044] The nanocrystalline Co-Ni alloy electroplating solution described in this article can be used in three-electrode electrochemical cells. (Reference) Figure 1 An exemplary system 100 is provided for using the nanocrystalline Co-Ni alloy electroplating solution described herein. System 100 includes an anode 102, a cathode 104, a reference electrode 106, and a nanocrystalline Co-Ni alloy electroplating solution 108 arranged in electrical communication within a three-electrode electrochemical cell 110. Specifically, the anode 102, cathode 106, nanocrystalline Co-Ni alloy electroplating solution 104, and reference electrode 106 are placed in the nanocrystalline Co-Ni alloy electroplating solution 108 and electrically connected to an electrochemical workstation 112 (such as a potentiostat / galvanometer), which is configured to apply a current, particularly a single-pulse square wave current, to the three-electrode electrochemical cell 110 to perform the electrochemical deposition of the nanocrystalline Co-Ni alloy as described herein. Optionally or additionally, system 100 may include a display 114, such as a computer display coupled to the electrochemical workstation 112, for monitoring the applied current, such as the current density, pulse width, waveform, etc.

[0045] In some embodiments, the system may also be configured to maintain the electrochemical cell (and thus the plating solution) at a substantially constant temperature during operation. Specifically, system 100 may include a temperature monitoring device 116, such as a water bath coupled to a heater with stirring function, in which the three-electrode electrochemical cell 110 may be placed during operation to achieve a constant temperature effect.

[0046] The nanocrystalline Co-Ni alloy electroplating solution described herein can be used according to the following method. The method may include the following steps: preparing the electroplating solution according to the following composition: 85 g·L -1 -100g·L -1 NiSO4·6H2O, 20g·L -1 -35g·L -1 CoSO4·7H2O, 45g·L -1 NiCl2·6H2O, 20g·L -1 H3BO3 and 2g·L -1 Saccharin; using a pretreated stainless steel plate as the cathode, a titanium plate as the anode, and a KCl saturated calomel electrode as the reference electrode, the cathode, the anode, and the reference electrode are placed in the electroplating solution; an electric current is passed between the electrodes to perform electrochemical deposition.

[0047] In some embodiments, the stainless steel sheet may be a 304 stainless steel sheet with dimensions, for example, 60mm x 20mm x 0.5mm. The 304 stainless steel sheet may be pretreated by the following steps: (1) polishing the first surface (working surface) of the 304 stainless steel with 2500-grit carbonized sandpaper; (2) mechanically polishing the first surface with 3μm–5μm Al2O3 polishing liquid until the first surface becomes mirror-like; (3) insulating the second surface (untreated / unpolished surface) with insulating materials such as insulating tape, thereby ensuring that electrochemical deposition occurs on a single desired surface.

[0048] In some embodiments, the titanium plate may have a purity of 99.99% and dimensions of 60mm x 20mm x 1mm. The titanium plate may be pretreated by the following steps to remove grease and other contaminants from its surface. Specifically, the titanium plate may be pretreated by: (1) polishing the titanium plate with 2500-grit silicon carbide sandpaper; (2) ultrasonically cleaning the polished titanium plate in acetone and alcohol for five minutes each and then drying it.

[0049] After completing the pretreatment steps described herein, a 304 stainless steel plate, a titanium plate, and a KCl-saturated calomel electrode can be placed in an electroplating solution and connected to the electrochemical workstation described herein, wherein the 304 stainless steel plate is the cathode, the titanium plate is the anode, and the KCl-saturated calomel electrode is the reference electrode. Specifically, the 304 stainless steel plate can be connected to the electrochemical workstation via the first surface described herein. Then, current can be applied to the electrodes to perform electrochemical deposition.

[0050] Electrochemical deposition can be performed under a single-pulse square wave current, more specifically, with a pulse width of 0.5 ms and a current density of 120 mA cm⁻¹. -2 The electrochemical deposition is performed under a single-pulse square wave current. The electrochemical deposition time can be modified according to actual needs. In some specific embodiments, electrochemical deposition can be performed for at least 24 hours.

[0051] In some embodiments, electrochemical deposition can be performed at temperatures ranging from 40°C to 50°C, such as 40°C to 49°C, 40.5°C to 50°C, 41°C to 50°C, 42.5°C to 48.4°C, 40°C to 47°C, 43.1°C to 47°C, 44°C to 46°C, and particularly at 45°C. The aforementioned temperatures can be achieved and maintained by a temperature monitoring device (e.g., a water bath coupled to a heater with a stirring function, as described herein).

[0052] In some embodiments, the electroplating bath can be stirred at a rate of 400 rpm to 600 rpm to promote electrochemical deposition, such as 410 rpm to 600 rpm, 400 rpm to 599 rpm, 413 rpm to 600 rpm, 415 rpm to 580 rpm, 420 rpm to 589 rpm, 425 rpm to 575 rpm, 440 rpm to 600 rpm, 400 rpm to 560 rpm, 480 rpm to 520 rpm, and especially 500 rpm.

[0053] The invention is described in more detail below by way of examples, but is not limited thereto.

[0054] Example

[0055] Microstructure characterization

[0056] The sample preparation process for transmission electron microscopy (TEM) is as follows: The deposited sample is polished to a thickness of 30 μm using SiC sandpaper with particle sizes of #1000, #1500, #2000, #2500 and #3000 respectively, and then a circular piece with a diameter of 3 mm is punched out using a punching machine. The disc was mounted on the chuck of a PIPS Model 695 Gatan ion thinning instrument for thinning. The initial accelerating voltage was set to 7 keV, the thinning angle to 6°, and the thinning time to 25 min. Maintaining the thinning angle, the accelerating voltage was reduced to 6 keV and run for 30 min. Maintaining the accelerating voltage, the thinning angle was set to 5°, and the thinning time was extended to 1 hour. The accelerating voltage was reduced to 5 keV, and the thinning angle was set to 4° until a hole was formed. Immediately after the hole was formed, the accelerating voltage was adjusted to 4 keV, and the thinning angle to 3°, extending the long side of the hole to approximately 150 μm. The accelerating voltage was reduced to 3 keV, and the thinning angle was reduced to 2° for 5 min. Finally, to improve the thinning quality and create a larger thin area, the accelerating voltage was adjusted to 2 keV while maintaining the thinning angle from the previous step, and the thinning was carried out again for 5 min. The ion thinning process was now complete.

[0057] The thinned sample was characterized for its microstructure and other structural features using a JEOL 2100F transmission electron microscope. The vacuum level was increased to 10... -5This operation can only be performed at the Pa level. First, find the perfect thin area, select an appropriate magnification, adjust the astigmatism and focal length, and then select a brightfield image as needed. Save the image, and then randomly select a region in the brightfield image to take a selected area electron diffraction (SAED) image. Determine the crystal structure of the material based on the SAED structure. Use a trackball to move the selected region to the center of the fluorescent screen, select a suitable-sized selection aperture and insert it into the optical path to capture the region of interest. Press the SA DIFF button to switch to diffraction mode, exit the objective aperture, and the diffraction pattern will appear on the fluorescent screen. Adjust the MAG / CAM L knob to the desired camera length, press PLA, use DEF / STIG to center the spot, adjust DIFF FOCUS to obtain a sharp diffraction spot, and simultaneously rotate BRIGHTNESS clockwise to darken the image sufficiently. Use a needle to block the central transmission spot. Keep the CCD in View, raise the fluorescent screen, press Stop View, quickly lower the fluorescent screen, and save the cutoff diffraction spot.

[0058] Mechanical property testing

[0059] The tensile sample is cut to size according to the given drawing, such as... Figure 2 As shown. Before stretching, the cutting marks on the side of the sample were sanded off with #2500 SiC sandpaper, and the cross-sectional dimensions within the gauge length were recorded. Then, stretching was performed on an MTS Criterion Model 43 stretching machine. The stretching equipment was equipped with an extensometer with a gauge length of 10 mm, and the strain rate was set to 2 x 10⁻⁶. -5 mms -1 After entering the dimensions, click "Run" on the operation interface until the sample breaks, at which point data acquisition will stop.

[0060] Compression performance was measured using a FUTURE-TECH FV-700 Vickers hardness tester. The surface of the deposited sample was ground smooth and then polished. Before measuring the hardness, the two parallel lines on the Vickers hardness gauge were aligned, ensuring the right edge of the left line was flush with the left edge of the right line. After alignment, the gauge was zeroed. A region of the sample surface was selected, the focus was adjusted, and the Start button was pressed. The needle was pressed down and held for 5 seconds. The length of the diagonal of the indentation was measured, and the system automatically recorded the data, finally yielding the hardness value.

[0061] Example 1

[0062] Preparation and structural characterization of nickel-rich nanocrystalline cobalt-nickel alloys

[0063] The following are examples of nickel-rich nanocrystalline cobalt-nickel alloys:

[0064] (1) Prepare the electroplating solution according to the following ratio: 100g / L nickel sulfate hexahydrate (NiSO4·6H2O) -120 g / L of cobalt sulfate heptahydrate (CoSO4·7H2O) -1 45g / L of nickel chloride hexahydrate (NiCl·6H2O) -1 Boric acid (H3BO3) 20g / L -1 2g / L of saccharin (C7H5NO3S) -1 .

[0065] (2) Grinding and cleaning the 304 stainless steel plate substrate: The 304 stainless steel plate connected to the cathode (working electrode) is 60mm x 20mm x 0.5mm in size. First, grind it with 2500-grit silicon carbide sandpaper, and then use Al2O3 polishing liquid with a particle size of 3-5μm for mechanical polishing until it becomes a mirror finish.

[0066] (3) Grinding and cleaning the titanium plate: The titanium plate connecting the anode (counter electrode) is 60mm x 40mm x 1mm in size. In order to remove grease and other stains from the surface of the titanium plate, it is ground with 2500-grit silicon carbide sandpaper. After grinding, it is placed in acetone and alcohol respectively for ultrasonic cleaning for five minutes and then dried.

[0067] (4) Single-phase pulse electrodeposition: To prevent deposition from occurring on both sides of the substrate, non-conductive adhesive is applied to the non-mirror side of the cleaned 304 stainless steel substrate, while the mirror side is connected to the cathode, known as the working electrode. A cleaned titanium plate is connected to the anode, and a saturated potassium chloride-filled calomel electrode is connected to the reference electrode. The other end of this three-electrode system is connected to an electrochemical workstation. The container holding the plating solution is placed in a magnetically stirred, constant-temperature water bath at 45°C, with a stirring speed of 500 rpm and a deposition current density of 120 mA / cm². -2 Each pulse opens (t) on ) and break (t) off The time for each phase is 0.5ms, and the total deposition time is 24h (i.e., the duration of the square wave pulse on and off in one cycle is set to 0.5ms, and the cycle time is 24h). Finally, nickel-rich nanocrystalline cobalt-nickel alloy is deposited.

[0068] like Figure 3A and 3B As shown, the nickel-rich nanocrystalline cobalt-nickel alloy possesses a single-phase face-centered cubic structure with an average grain size of 24 nm. Mechanical property tests indicate that the yield strength of the nickel-rich nanocrystalline cobalt-nickel alloy is σ. y =1404.5MPa Figure 4 Besides tensile elongation, the dimple structure of the fracture surface can also be used to judge the plasticity of a material. Nickel-rich nanocrystalline cobalt-nickel alloys exhibit abundant and uniformly distributed dimple structures on their tensile fracture surfaces, with micron-sized dimples (6.4 μm). Figure 5The results indicate that the nickel-rich nanocrystalline cobalt-nickel alloy exhibits high tensile plasticity. Due to these excellent mechanical properties, the nickel-rich nanocrystalline cobalt-nickel alloy of this invention is particularly suitable for applications requiring high mechanical properties, such as surface coatings. Furthermore, the nickel-rich nanocrystalline cobalt-nickel alloy of this invention possesses a certain degree of magnetism, and its nanoscale characteristics can improve magnetic coercivity and saturation magnetization. Due to the enhanced magnetism, the nickel-rich nanocrystalline cobalt-nickel alloy of this invention shows great promise for application in the production of permanent magnets, magnetic sensors, and data storage devices. Further, the nickel-rich nanocrystalline cobalt-nickel alloy of this invention exhibits good corrosion resistance, making it suitable for harsh environments, such as marine environments or applications requiring chemical corrosion resistance.

[0069] Example 2

[0070] Preparation and structural characterization of cobalt-rich nanocrystalline cobalt-nickel alloys

[0071] The following are examples of cobalt-rich nanocrystalline cobalt-nickel alloys:

[0072] (1) Prepare the electroplating solution according to the following ratio: 85 g / L nickel sulfate hexahydrate (NiSO4·6H2O) -1 35 g / L of cobalt sulfate heptahydrate (CoSO4·7H2O) -1 45g / L of nickel chloride hexahydrate (NiCl·6H2O) -1 Boric acid (H3BO3) 20g / L -1 2g / L of saccharin (C7H5NO3S) -1 .

[0073] (2) Grinding and cleaning the 304 stainless steel plate substrate: The 304 stainless steel plate connected to the cathode (working electrode) is 60mm x 20mm x 0.5mm in size. First, grind it with 2500-grit silicon carbide sandpaper, and then use Al2O3 polishing liquid with a particle size of 3-5μm for mechanical polishing until it becomes a mirror finish.

[0074] (3) Grinding and cleaning the titanium plate: The titanium plate connecting the anode (counter electrode) is 60mm x 40mm x 1mm in size. In order to remove grease and other stains from the surface of the titanium plate, it is ground with 2500-grit silicon carbide sandpaper. After grinding, it is placed in acetone and alcohol respectively for ultrasonic cleaning for five minutes and then dried.

[0075] (4) Single-phase pulse electrodeposition: To prevent deposition from occurring on both sides of the substrate, non-conductive adhesive is applied to the non-mirror side of the cleaned 304 stainless steel substrate, while the mirror side is connected to the cathode, known as the working electrode. A cleaned titanium plate is connected to the anode, and a saturated potassium chloride-filled calomel electrode is connected to the reference electrode. The other end of this three-electrode system is connected to an electrochemical workstation. The container holding the plating solution is placed in a magnetically stirred, constant-temperature water bath at 45°C, with a stirring speed of 500 rpm and a deposition current density of 120 mA cm⁻¹. -2 Each pulse opens (t) on ) and break (t) off The deposition time was 0.5 ms for each deposition, and the total deposition time was 24 h. Finally, a cobalt-rich nanocrystalline cobalt-nickel alloy was deposited.

[0076] like Figure 6A and 6B As shown, the nickel-rich nanocrystalline cobalt-nickel alloy has a single-phase face-centered cubic structure with an average grain size of 17 nm. Mechanical property tests show that the yield strength of the cobalt-rich nanocrystalline cobalt-nickel alloy is σ. y =1276MPa Figure 7 The tensile fracture morphology of the cobalt-rich nanocrystalline cobalt-nickel alloy shows that micron-sized fracture dimples (1.4 μm) are uniformly distributed at the fracture surface. Figure 8 The results indicate that the cobalt-rich nickel-based nanocrystalline cobalt-nickel alloy possesses high tensile plasticity. Due to these excellent mechanical properties, the cobalt-rich nanocrystalline cobalt-nickel alloy of this invention is particularly suitable for applications requiring high mechanical properties, such as surface coatings. Furthermore, the cobalt-rich nanocrystalline cobalt-nickel alloy of this invention exhibits a certain degree of magnetism, and its nanoscale characteristics can improve magnetic coercivity and saturation magnetization. Due to the enhanced magnetism, the cobalt-rich nanocrystalline cobalt-nickel alloy of this invention shows great promise for application in the production of permanent magnets, magnetic sensors, and data storage devices. Further, the cobalt-rich nanocrystalline cobalt-nickel alloy of this invention exhibits good corrosion resistance, making it suitable for harsh environments, such as marine environments or applications requiring chemical corrosion resistance.

[0077] The invention is given by way of example only, and various other modifications and / or alterations may be made to the described embodiments by those skilled in the art without departing from the scope of the invention as specified in the appended claims.

Claims

1. A nanocrystalline Co-Ni alloy, characterized in that, The nanocrystalline Co-Ni alloy comprises the chemical formula Co. x Ni 1-x x is the atomic percentage, and 38 ≤ x ≤ 60.

2. The nanocrystalline Co-Ni alloy as described in claim 1, characterized in that, The nanocrystalline Co-Ni alloy has a single-phase face-centered cubic crystal structure.

3. The nanocrystalline Co-Ni alloy as described in claim 1, characterized in that, The average grain size of the nanocrystalline Co-Ni alloy is between 17 nm and 24 nm.

4. The nanocrystalline Co-Ni alloy as described in claim 1, characterized in that, The yield strength of the nanocrystalline Co-Ni alloy is 1200 MPa to 1500 MPa.

5. The nanocrystalline Co-Ni alloy as described in claim 1, characterized in that, The tensile plasticity of the nanocrystalline Co-Ni alloy is 8% to 10%.

6. The nanocrystalline Co-Ni alloy as described in claim 1, characterized in that, The compressive strength of the nanocrystalline Co-Ni alloy is 5500 MPa to 6000 MPa.

7. The nanocrystalline Co-Ni alloy as described in claim 1, characterized in that, The nanocrystalline Co-Ni alloy is a Ni-rich nanocrystalline Co-Ni alloy and has the chemical formula Co. 38 Ni 62 .

8. The nanocrystalline Co-Ni alloy as described in claim 1, characterized in that, The nanocrystalline Co-Ni alloy is a Co-rich nanocrystalline Co-Ni alloy and has the chemical formula Co. 60 Ni 40 .

9. The nanocrystalline Co-Ni alloy as described in claim 7, characterized in that, The yield strength of the Ni-rich nanocrystalline Co-Ni alloy is 1404.5 MPa.

10. The nanocrystalline cobalt-nickel alloy as described in claim 7, characterized in that, The yield strength of the Co-rich nanocrystalline Co-Ni alloy is 1276 MPa.

11. A nanocrystalline Co-Ni alloy electroplating solution, wherein the chemical formula of the nanocrystalline Co-Ni alloy is Co. x Ni 1-x Where x is the atomic percentage, 38≤x≤60, characterized in that, The nanocrystalline Co-Ni alloy electroplating solution comprises: 85 g·L -1 -100g·L -1 NiSO4·6H2O, 20g·L -1 -35g·L -1 CoSO4·7H2O, 45g·L -1 NiCl2·6H2O, 20g·L -1 H3BO3 and 2g·L -1 saccharin.

12. The nanocrystalline Co-Ni alloy electroplating solution as described in claim 11, characterized in that, The pH value of the nanocrystalline Co-Ni alloy electroplating solution is 3.5-3.

8.

13. The method of using the nanocrystalline Co-Ni alloy electroplating solution as described in claim 11, characterized in that, The method includes the following steps: The electroplating solution was prepared according to the following composition: 85 g·L -1 -100g·L -1 NiSO4·6H2O, 20g·L -1 -35g·L - 1 CoSO4·7H2O, 45g·L -1 NiCl2·6H2O, 20g·L -1 H3BO3 and 2g·L -1 saccharin; Using a pretreated stainless steel plate as the cathode, a titanium plate as the anode, and a KCl saturated calomel electrode as the reference electrode, the cathode, the anode, and the reference electrode are placed in the electroplating solution. Electrochemical deposition is performed by passing an electric current between the electrodes.

14. The method as described in claim 13, characterized in that, The current is a single-pulse square wave current with a pulse width of 0.5 ms and a current density of 120 mA cm⁻¹. -2 .

15. The method as described in claim 13, characterized in that, The electrochemical deposition process takes at least 24 hours.

16. The method as described in claim 13, characterized in that, The electrochemical deposition was performed at a temperature of 40°C to 50°C.

17. The method as described in claim 13, characterized in that, The electroplating solution is stirred at a rate of 400 rpm to 600 rpm.

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