CN110565032A

CN110565032A - Amorphous fiber with giant magneto-impedance effect and preparation method and application thereof

Info

Publication number: CN110565032A
Application number: CN201910876514.6A
Authority: CN
Inventors: 姜思达; 孙剑飞; 曹福洋; 付振华
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2019-09-17
Filing date: 2019-09-17
Publication date: 2019-12-13

Abstract

An amorphous fiber with giant magneto-impedance effect and a preparation method and application thereof belong to the technical field of application of functional materials. In order to improve the giant magneto-impedance effect of the amorphous fiber, the invention adopts a direct current electroplating process to prepare a ferromagnetic shell layer on the outer layer of the amorphous fiber to obtain the giant magneto-impedance effect amorphous fiber with an amorphous core part and the ferromagnetic shell layer, and the amorphous fiber component is Co_68.15Fe_4.35Si_12.25B_13.25Zr₂Or Cu₄₈Zr₄₈Al₄The component of the ferromagnetic coating is Ni_80‑XFe_20+XAn alloy wherein X is 0-10. The invention can be used for preparing a high-sensitivity magnetic sensor.

Description

Amorphous fiber with giant magneto-impedance effect and preparation method and application thereof

Technical Field

The invention belongs to the technical field of application of functional materials, and particularly relates to an amorphous fiber with a giant magneto-impedance effect, and a preparation method and application thereof.

Background

The amorphous fiber microstructure is short-range ordered long-range disorder, has the characteristics of smaller hysteresis loss and coercive force, negative or near zero magnetostriction coefficient, high permeability, special magnetic domain structure, Skin Effect (Skin Effect) and the like, and particularly has the obvious giant magneto-impedance Effect (GMI) under higher frequency which is obviously superior to other types of materials such as amorphous ribbon, magnetic film, electro-deposition composite fiber and the like, so the amorphous fiber is more suitable to be used as a novel sensitive material for GMI magnetic sensors (see V.Zhukova, M.Ipav, A.Zhukov.thin magnetic Soft magnetic force for magnetic sensors, Sensors.2009,9: 9216-9240) and is practically applied to miniaturized high-sensitivity magnetic sensors. At present, the research on the characteristics of the amorphous fiber with the performance at home and abroad has not been reported.

Disclosure of Invention

In order to improve the giant magneto-impedance effect of the amorphous fiber, the invention provides the amorphous fiber with the giant magneto-impedance effect, the amorphous fiber is obtained by preparing a ferromagnetic shell layer on the outer layer of the amorphous fiber by adopting a direct current electroplating process, the amorphous fiber with the giant magneto-impedance effect of an amorphous core part and the ferromagnetic shell layer is obtained, and the component of the amorphous fiber is Co_68.15Fe_4.35Si_12.25B_13.25Zr₂Or Cu₄₈Zr₄₈Al₄The component of the ferromagnetic coating is Ni_80-XFe_20+Xan alloy wherein X is 0-10.

Is further defined by Co_68.15Fe_4.35Si_12.25B_13.25Zr₂Amorphous fiber as component, the diameter of amorphous core is 42 μm + -1 μm, and the thickness of ferromagnetic shell is 19.1 μm + -0.2 μm; with Cu₄₈Zr₄₈Al₄The amorphous fiber core as component has diameter of 49 μm + -1 μm and ferromagnetic shell layer thickness of 15.5 μm + -0.4 μm.

The invention also provides a preparation method of the amorphous fiber with the giant magneto-impedance effect, which is characterized in that a melt drawing method is used for preparing the amorphous fiber, the amorphous fiber is used as a core part, a ferromagnetic shell layer is prepared on the outer layer of the amorphous fiber by adopting a direct current electroplating process, the giant magneto-impedance effect amorphous fiber with the amorphous core part and the ferromagnetic shell layer is obtained, and the cathode current density adopted in the direct current electroplating process is 4-12A/dm²Electroplating time of 5-30min, electroplating temperature of 50-80 deg.C, pH value of 2.5-5, and anode of Ni_80- _XFe_20+XAn alloy in which X is 0 to 10 and the cathode isAmorphous fiber.

Further defining a cathodic current density of 6A/dm for use in said direct current electroplating process²Electroplating time is 20min, the temperature of the electroplating solution is 60 ℃, and the pH value is 3.5.

Further, the main salt component of the electroplating solution adopted in the direct current electroplating process is nickel sulfate (NiSO)₄·7H₂O and FeSO₄·7H₂O。

Further defined, the formula of the electroplating solution is that each liter contains nickel sulfate NiSO₄·7H₂200g of O and FeSO₄·7H₂O12g, boric acid 40g, sodium chloride 20g, sodium citrate 20g, sodium benzene sulfinate 0.2g, sodium dodecyl sulfate 0.2g, saccharin 3g, brightener 2g, and the balance of water.

The amorphous fiber with the giant magneto-impedance effect can be used for preparing a magnetic sensor.

Advantageous effects

the invention selects the direct current electroplating process which is simple to operate, easy to popularize and low in cost to prepare the ferromagnetic shell layer of the plating layer composite structure micro-wire to obtain the amorphous core/ferromagnetic shell layer giant magneto-impedance effect composite structure micro-wire.

Drawings

FIG. 1a) is Co_68.15Fe_4.35Si_12.25B_13.25Zr₂Amorphous fiber surface topography, b) electroplating Ni₈₀Fe₂₀Surface of rear microfilament and c) cross-sectional SEM image in which NiFe is Ni₈₀Fe₂₀Alloy, Co-based microwire means Co_68.15Fe_4.35Si_12.25B_13.25Zr₂；

FIG. 2Co_68.15Fe_4.35Si_12.25B_13.25Zr₂Amorphous fiber and electroplated Ni thereof₈₀Fe₂₀The ratio of the giant magneto-impedance and the impedance are plotted along with the frequency and the external magnetic field, wherein the abscissa in a) and b) is the frequency, and the ordinate is the impedance ratio and the impedance respectively; wherein c) and d) the coordinates in the horizontal axis are equivalent anisotropic fields, and the coordinates in the vertical axis are respectively an impedance ratio and impedance;

FIG. 3Cu₄₈Zr₄₈Al₄Amorphous fiber plated with Ni₈₀Fe₂₀The back surface of the coating, a) in the figure, and a cross-sectional SEM topography, b) thereof, wherein NiFe represents Ni₈₀Fe₂₀CuZrAl stands for Cu₄₈Zr₄₈Al₄；

FIG. 4Cu₄₈Zr₄₈Al₄Amorphous fiber plated with Ni₈₀Fe₂₀The impedance ratio and the impedance after coating change with the external magnetic field and the frequency, wherein the abscissa in a) is the frequency, wherein the b) is the equivalent anisotropic field, and the ordinate is the impedance ratio.

Detailed Description

The following embodiment of the invention is to carry out electroplating treatment on melt drawing amorphous fiber to obtain amorphous fiber with an amorphous core part/ferromagnetic shell layer composite structure, thereby improving giant magnetoresistance impedance performance.

The amorphous fiber prepared by the invention contains Co as the component_68.15Fe_4.35Si_12.25B_13.25Zr₂Or Cu₄₈Zr₄₈Al₄The electroplating parameters are set as that the cathode current density is 4-12A/dm²Electroplating time of 5-30min, electroplating temperature of 50-80 deg.C, pH value of 2.5-5, and anode of Ni_80-XFe_20+XThe alloy, wherein X is 0-10, and the cathode is amorphous fiber. The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

The melt draw method described in the present invention is a method conventional in the art and is described by way of example as follows:

The mother alloy for drawing the melt is molten and cast in a vacuum magnetically controlled tungsten arc furnace with vacuum degree of 10^-4Pa, power supply heating power of 18-20kW, linear speed of a Cu roller of 20-25m/s, feeding speed of master alloy of 30 mu m/s and included angle of the roller of 60 degrees. The preparation method is described as follows:

The main process is as follows: after the raw materials are cleaned and processed, the raw materials are proportioned by an electronic balance with the precision of one ten thousandth according to nominal components, and the light and volatile components or the low-melting-point raw materials are placed under a large block of high-melting-point components to reduce volatilization. Before smelting, the electric arc furnace is firstly vacuumized to 10 degrees^-4Pa, then is filled withArgon (Ar, 99.97%) was introduced as a protective atmosphere. Titanium is smelted in a titanium smelting crucible for about 2 minutes to remove residual oxygen in the smelting chamber, and then alloy smelting is carried out. In order to ensure the uniformity of alloy components, electromagnetic stirring is utilized in the smelting process to ensure the full mixing among the components. And after the master alloy is melted, carrying out suction casting on the melted master alloy to obtain a master alloy rod with the diameter of 10mm and the length of 10-15 cm. And (3) placing the smelted master alloy bar in a BN crucible, and adjusting the distance and the placement position between the crucible and the roller. The equipment is pre-vacuumized, protective gas is filled in the equipment, and simultaneously the metal drawing roller with the preset rotating speed is started to be used as the exploration and optimization of process parameters, and the rotating interval of the roller is between 500rad/min and 4000 rad/min. And starting an induction melting power supply after the rotating roller reaches a preset rotating speed and runs stably, adjusting induction heating power to measure the actual temperature and superheat degree of the melt after the master alloy is completely melted to form a steamed bun-shaped surface, starting the feeding of the master alloy, and preparing the amorphous microwire by utilizing the tip edge of the rapidly rotating copper roller.

Comparative example 1 preparation of Co Using melt Czochralski method_68.15Fe_4.35Si_12.25B_13.25Zr₂And (5) amorphous fiber, and finishing the impedance test.

EXAMPLE 1 Co with giant magneto-impedance Effect_68.15Fe_4.35Si_12.25B_13.25Zr₂And (4) preparing amorphous fibers.

Preparation of Co by melt drawing method_68.15Fe_4.35Si_12.25B_13.25Zr₂Amorphous fiber (Co-based microwire for short) is treated by electroplating with electroplating parameters set to cathode current density of 6A/dm²Electroplating time is 20min, temperature of the plating solution is 60 ℃, pH value is 3.5, and anode is Ni₈₀Fe₂₀The alloy, core diameter 42 μm. + -. 1 μm, and coating (also called shell) thickness 19.1 μm. + -. 0.2 μm, completed the impedance test.

The specific method of electroplating treatment is as follows: the method is characterized in that the cathode wire (amorphous fiber) needs to be pretreated before direct current electroplating, and the specific implementation flow is as follows: deionized water washing → weak alkaline washing → deionized water washing → acid washing → deionized water washing → direct current electroplating, and the formulas of the weak alkaline washing solution and the acid washing solution are shown in tables 1 and 2. The cathode wire and the anode permalloy are easy to adhere a small amount of oil dirt on the surface in the previous preparation and forming process. It contaminates the plating solution, makes the plating layer not firmly bonded to the wire substrate, and causes plating defects such as blistering and flaking, and therefore, the oil stains on the surface must be cleaned before plating. After the caustic soda and the sodium carbonate are deoiled, the residual alkali on the surface of the cathode wire is not easy to wash poorly, and is easy to neutralize with acid during reactivation and salt is easy to attach. The trisodium phosphate has better water-washing property, the residual alkali on the surface of a workpiece is easy to clean after the trisodium phosphate is added, and the sodium carbonate and the trisodium phosphate are often added into an oil removing solution, and the addition amount of the trisodium phosphate is larger than that of the trisodium phosphate. The pickling is chemical cleaning, in which a solvent made of an acid (inorganic acid/organic acid) as a main agent dissolves and peels off an oxide layer, rust, welding slag, and the like, which are coated on the surface of a metal material, equipment, and the like, through a chemical reaction. The technology has the advantages of high cleaning speed, good effect and easy operation and control, and is widely applied at present. The amorphous fiber is in a preparation state, a groove formed by drawing is formed, a small amount of oxide exists on the surface after annealing treatment (320 ℃, 3 hours), the defects can be effectively removed by acid washing, and the surface can be slightly corroded and activated and the coating can be combined more tightly to improve the tensile fracture reliability.

The electroplating device adopts a multifunctional water bath crucible with an electromagnetic stirring function, the electromagnetic stirring can prevent the electroplating solution from generating deposition in the preparation process of the coating, the components of the coating and the like are more uniform, the rotating speed is set to be 15-20 r/min, the inter-polar distance is set to be 35-40mm, and the length of the cathode wire is 3 cm. The formulation of the plating solution is shown in Table 3, and the influence of the contents of the components of the solution on the quality of the plated layer from the viewpoint of electrochemical deposition was analyzed. The main salt component of the electroplating solution is nickel sulfate NiSO₄·7H₂O and FeSO₄·7H₂O, when nickel sulfate NiSO₄·7H₂When the content of the O component is too high, the cathode polarization and the deep plating capability are weakened, so that the brittleness of the plating layer is increased, and when the content is lower, the current density and the deposition speed are increased, but the corrosion resistance of the plating layer is reduced; ferrous sulfate FeSO₄·7H₂When the content of the O component is too high, the yellow spots are liable to appear on the surface of the plating layer, and when the content is lowNickel ions cannot be saved, and the surface layer cannot obtain the required glossiness; the sodium chloride NaCl plays a role in activating in the solution, can increase the conductivity and the deposition speed, and has overhigh content, overhigh dissolution speed of the anode, lower content and easy passivation of the anode; boric acid H₃BO₃Mainly plays a role of a pH value buffering agent, can stabilize the pH value of a cathode area, improves cathode polarization and improves the quality of a plating layer; sodium citrate is the main stabilizer and can stabilize Fe³⁺To form a complex and prevent the generation of iron hydroxide precipitate; sodium dodecyl sulfate is a surfactant to prevent hydrogen from attaching to the surface layer to generate pinholes in the preparation process; sodium benzene sulfinate is used as an auxiliary brightener to be matched with the brightener, so that the coating in a low-current region of the cathode can be prevented from darkening, the brightness of the coating is higher, the tensile stress of the coating can be reduced, and the brittleness, low content, poor leveling property of the coating, high content and poor gloss of the coating are avoided; saccharin as a reducing agent can make Fe in solution³⁺Reduction to Fe²⁺And the plating layer can be crystallized finely and has luster.

TABLE 1 Weak base degreasing solution formulation and associated process conditions

TABLE 2 cathodic and anodic pickling solution formulations and associated process conditions

TABLE 3 DC ELECTROPLATING SOLUTION FORMULATIONS AND RELATED PROCESS CONDITIONS

EXAMPLE 2 Cu with giant magneto-impedance Effect₄₈Zr₄₈Al₄And (4) preparing amorphous fibers.

Preparation of Cu by melt drawing method₄₈Zr₄₈Al₄Amorphous fiber, then electroplating, setting parametersTo that end, the cathode current density is 6A/dm²Electroplating time is 20min, temperature of the plating solution is 60 ℃, pH value is 3.5, and anode is Ni₈₀Fe₂₀The alloy, core diameter 49 μm. + -. 1 μm, and plating (also referred to as cladding) thickness 15.5 μm. + -. 0.4 μm, completed the impedance test. Having Cu as described in this example₄₈Zr₄₈Al₄The amorphous fiber is described with reference to example 1.

Example 3. example 1 was repeated, differing from example 1 in that the cathodic current density used in this example was 4A/dm²Electroplating time is 30min, temperature of the plating solution is 80 ℃, and pH value is 2.5.

Example 4 example 2 was repeated, differing from example 2 in that the cathodic current density used in this example was 12A/dm²Electroplating time is 5min, temperature of the plating solution is 50 ℃, and pH value is 5.

The resistance of the amorphous fiber prepared by the electroplating method of the present invention is described below by taking examples 1 and 2 as examples.

Comparative example 1 and examples 1 to 2 were analyzed, and the data of the measurements are shown in FIGS. 1 to 4.

In FIG. 1a) is Co_68.15Fe_4.35Si_12.25B_13.25Zr₂Amorphous fiber surface topography, b) electroplating Ni₈₀Fe₂₀The rear microfilament surface and c) is a cross-sectional SEM image; i.e. b) and c) are the microstructures of example 1.

From FIG. 2, without plating Ni₈₀Fe₂₀Before lamination, the Co-based micro-wire giant magneto-impedance effect ratio and the impedance are increased and then reduced along with the increase of the frequency, the maximum value, namely the characteristic frequency, is obtained at 12MHz, and the maximum impedance ratio is 550 percent; in electroplating of Ni₈₀Fe₂₀After coating, the impedance ratio and the characteristic of impedance variation along with frequency are not changed, but the characteristic frequency is reduced to 3MHz, the maximum impedance ratio is reduced to 190 percent, and the obtained maximum impedance frequency is shifted to 90MHz from 20MHz, as shown in a) and b) in figure 2; the impedance ratio and the impedance before and after electroplating are in a monotonous descending trend along with the change of an external magnetic field, namely, the single-peak characteristic is presented, the impedance ratio is obviously reduced after electroplating, the essential reason is that the impedance value is reduced, and the impedance before electroplating is 2 from zero external field37 omega is reduced to 36 omega when the maximum external field is reduced, and the impedance value of the zero external field after electroplating is reduced to 23 omega when the maximum external field is reduced to 8 omega, as shown in c) and d) in figure 2. I.e. the giant magneto-impedance effect exists after electroplating.

Cu shown in FIG. 3₄₈Zr₄₈Al₄Amorphous fiber plated with Ni₈₀Fe₂₀SEM topography of the back surface and the section of the plating layer, the diameter of the core part is 49 microns +/-1 micron, and the thickness of the plating layer is 15.5 microns +/-0.4 micron. The impedance ratio and the impedance change rule along with the exciting current frequency and the external magnetic field are shown in figure 4, the characteristic frequency is lower and is 5MHz, the impedance and the impedance ratio monotonically decrease along with the external magnetic field and present a single peak characteristic, the impedance value is still lower and is less changed along with the external magnetic field, the core is a non-magnetic low-conductivity amorphous material, the giant magneto-impedance effect is avoided, and the giant magneto-impedance effect is generated after electroplating.

Claims

1. The amorphous fiber with giant magneto-impedance effect is characterized in that a ferromagnetic shell layer is prepared on the outer layer of the amorphous fiber by adopting a direct current electroplating process to obtain the amorphous fiber with the giant magneto-impedance effect of an amorphous core part and the ferromagnetic shell layer, and the amorphous fiber is Co_68.15Fe_4.35Si_12.25B_13.25Zr₂Or Cu₄₈Zr₄₈Al₄The ferromagnetic shell layer component is Ni_80-XFe_20+XAn alloy wherein X is 0-10.

2. The amorphous fiber according to claim 1, wherein Co is used_68.15Fe_4.35Si_12.25B_13.25Zr₂Amorphous fiber as component, the diameter of amorphous core is 42 μm + -1 μm, and the thickness of ferromagnetic shell is 19.1 μm + -0.2 μm; with Cu₄₈Zr₄₈Al₄The amorphous fiber core as component has diameter of 49 μm + -1 μm and ferromagnetic shell layer thickness of 15.5 μm + -0.4 μm.

3. a method for preparing an amorphous fiber according to claim 1 or 2, wherein the amorphous fiber is prepared by a melt drawing method using the amorphous fiber as a core portionPreparing ferromagnetic shell layer on the outer layer of amorphous fiber by direct current electroplating process to obtain giant magneto-impedance effect amorphous fiber with amorphous core and ferromagnetic shell layer, wherein cathode current density adopted in the direct current electroplating process is 4-12A/dm²Electroplating time of 5-30min, electroplating temperature of 50-80 deg.C, pH value of 2.5-5, and anode of Ni_80-XFe_20+XThe alloy, wherein X is 0-10, and the cathode is amorphous fiber.

4. The method according to claim 3, characterized in that the cathodic current density employed in said galvanic plating process is 6A/dm²Electroplating time is 20min, the temperature of the electroplating solution is 60 ℃, and the pH value is 3.5.

5. The method according to claim 3, wherein the main salt component of the plating solution used in the DC electroplating process is NiSO₄·7H₂O and FeSO₄·7H₂O。

6. The method as claimed in claim 5, wherein said plating solution is formulated to contain nickel sulfate NiSO per liter₄·7H₂200g of O and FeSO₄·7H₂O12g, boric acid 40g, sodium chloride 20g, sodium citrate 20g, sodium benzene sulfinate 0.2g, sodium dodecyl sulfate 0.2g, saccharin 3g, brightener 2g, and the balance of water.

7. Use of the amorphous fiber having giant magneto-impedance effect according to claim 1 or 2 for the preparation of a magnetic sensor.