阅读说明：本技术 一种提高Co基非晶纤维巨磁阻抗性能的方法 (Method for improving giant magnetic impedance performance of Co-based amorphous fiber ) 是由 姜思达 孙剑飞 曹福洋 于 2019-09-17 设计创作，主要内容包括：一种提高Co基非晶纤维巨磁阻抗性能的方法,属于功能材料的应用技术领域。为了提高非晶纤维阻抗性能,本发明提供了一种提高Co基非晶纤维巨磁阻抗性能的方法,是指对Co基非晶纤维施加偏置电流,所述偏置电流大小为2.5mA-180mA,外部激励磁场周期为2-5min,大小为0.5-2.5Oe；所述Co基非晶纤维为Co<Sub>68.15</Sub>Fe<Sub>4.35</Sub>Si<Sub>12.25</Sub>B<Sub>13.25</Sub>Zr<Sub>2</Sub>。本发明具有优异巨磁阻抗性能,可用于传感器的制备。(A method for improving giant magnetic impedance performance of Co-based amorphous fiber belongs to the technical field of application of functional materials. In order to improve the impedance performance of the amorphous fiber, the invention provides a method for improving the giant magnetic impedance performance of the Co-based amorphous fiber, which is characterized in that bias current is applied to the Co-based amorphous fiber, the magnitude of the bias current is 2.5mA-180mA, the period of an external excitation magnetic field is 2-5min, and the magnitude is 0.5-2.5 Oe; the Co-based amorphous fiber is Co 68.15 Fe 4.35 Si 12.25 B 13.25 Zr 2 . The invention has excellent giant magnetic impedance performance and can be used for preparing sensors.)

1. A method for improving giant magneto-impedance performance of Co-based amorphous fiber is characterized in that bias current is applied to the Co-based amorphous fiber, the magnitude of the bias current is 2.5mA-180mA, the period of an external excitation magnetic field is 2-5min, and the magnitude is 0.5-2.5 Oe; the Co-based amorphous fiber is Co_68.15Fe_4.35Si_12.25B_13.25Zr₂。

2. The method according to claim 1, wherein the Co-based amorphous fiber has a diameter of 50 ± 1 μm.

3. the method according to claim 1, wherein the Co-based amorphous fiber is prepared by a melt drawing method.

4. The method of claim 3, whereinThe melt drawing method is carried out in high-vacuum precise melt drawing equipment, and the vacuum degree is 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.

5. The method of claim 1, wherein the bias current is 30mA, the external excitation field period is 2min, and the magnitude is 2.5 Oe.

Technical Field

The invention belongs to the technical field of application of functional materials, and particularly relates to a method for improving giant magneto-impedance performance of Co-based amorphous fibers.

Background

the amorphous fiber microstructure is short-range ordered long-range disorder, and has the characteristics of smaller hysteresis loss, coercive force, negative or near-zero magnetostriction coefficient, high magnetic conductivity, special magnetic domain structure, Skin Effect (Skin Effect) and the like, and particularly, the obvious giant magneto-impedance Effect (GMI) at higher frequency is obviously superior to other types of materials such as an amorphous ribbon, a magnetic film, an 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, the GMI magnetic sensors are practically applied to miniaturized high-sensitivity magnetic sensors, and the impedance performance and the sensitivity have improved spaces at present. The preparation research of the amorphous fiber at home and abroad has not been reported.

Disclosure of Invention

In order to improve the impedance performance of the amorphous fiber, the invention provides a method for improving the giant magnetic impedance performance of the Co-based amorphous fiber, which is characterized in that bias current is applied to the Co-based amorphous fiber, the magnitude of the bias current is 2.5mA-180mA, the period of an external excitation magnetic field is 2-5min, and the magnitude is 0.5-2.5 Oe; the Co-based amorphous fiber is Co_68.15Fe_4.35Si_12.25B_13.25Zr₂。

Further defined, the diameter of the Co-based amorphous fiber is 50 +/-1 μm.

Further, the Co-based amorphous fiber is prepared by a melt drawing method.

Further, the melt drawing method is carried out in a high-vacuum precise melt drawing device, and the vacuum degree is 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.

Further, the bias current is 30mA, the period of the external excitation magnetic field is 2min, and the magnitude is 2.5 Oe.

Advantageous effects

Compared with the prior art, the invention has the following advantages: under the condition that small-amplitude bias current does not influence the displacement of a surface domain wall and the rotation of a magnetic moment, the intrinsic impedance value of the microwire is greatly reduced by increasing the axial angle and the skin depth of an annular magnetic domain, the impedance increment of an external excitation magnetic field is improved at the same time, and the impedance ratio, delta Z/Z, of the microwire is further remarkably increased₀Can exceed 1800 percent, and the intrinsic impedance value of the microwire is recovered after the bias current source is turned off. The giant magnetoresistance material has excellent giant magnetoresistance impedance performance, and can meet the requirement of a sensor on higher precision in practical application.

Drawings

FIG. 1 is a schematic diagram of applying a 2.5Oe periodic external excitation magnetic field in an amorphous fiber impedance test under the action of real-time monitoring of a bias current;

FIG. 2 shows a data graph of the variation of the impedance, resistance and inductive reactance of the amorphous fiber applied with 2.5Oe periodic external excitation magnetic field under the action of bias currents with different amplitudes. In the figure, the blue line shows the change of the fiber impedance and the like under the action of the periodic external field when no bias current passes through the fiber, and the red line shows the change of the fiber impedance and the like under the action of the periodic external field after the bias current passes through the fiber. The abscissa is time, the ordinates in a) and b) in the figure are impedance Z, and the ordinates in c) and d) in the figure are resistance R; the ordinate in graphs e) and f) is the inductive reactance L;

FIG. 3 fiber zero out-field impedance Z₀The maximum impedance difference value delta Zmax and the equivalent anisotropy field Hk are changed along with the bias current, the abscissa is the current value, wherein, a) is a blue histogram (delta Z)₀) The ordinate is zero external field impedance, the ordinate of the red histogram (Δ Zmax) is the maximum impedance difference, b) the ordinate is the equivalent anisotropy field;

FIG. 4 shows the changes of the impedance, resistance and inductance values in the fiber preparation state and 140mA treatment and after treatment, wherein a) is the preparation state, b) is the annealing treatment, and c) is the annealing treatment, the abscissa of each graph is the equivalent anisotropy field, and the ordinate is the impedance Z, the resistance R and the inductance L of the three states;

FIG. 5 shows the variation of the giant magneto-impedance performance of amorphous fiber under the action of different small-amplitude DC bias currents at an excitation current frequency of 200MHz and after the large-amplitude bias current is turned off (i.e., regulated and controlled); wherein a) applying small bias current of different amplitudes amorphous fiber impedance changes; b) applying large bias current with different amplitudes to change the impedance of the amorphous fiber; c) the resistance of the amorphous fiber is changed for applying small bias currents with different amplitudes; d) the resistance of the amorphous fiber is changed for applying large bias current with different amplitudes; e) the amorphous fiber inductive reactance changes for applying small bias currents with different amplitudes; f) applying large bias current with different amplitudes to change the inductive reactance of the amorphous fiber; the three-axis coordinates are respectively current, equivalent anisotropic field, impedance Z, resistance R and inductive reactance L.

Detailed Description

the invention applies bias current under high frequency domain to improve the giant magneto-impedance performance of the amorphous fiber with composite structure, and detects the change of impedance, resistance and inductance.

In accordance with the above objects, the present invention applies a bias current to an amorphous fiber having a composite structure to improve its impedance performance. FIG. 1 is a schematic diagram showing the application of a periodic external field in a fiber impedance test under the action of real-time monitoring of a bias current. The high-frequency impedance analyzer HP4192 is connected with the amorphous fiber by a two-terminal method, and the bias current is provided by a PASCO multifunctional current source and is connected with the amorphous fiber testing terminal in parallel. The external magnetic field is provided by a ferromagnet when the impedance performance change is monitored in real time, the size is adjusted through the distance, the external field application period is 2-5min, and the size is 0.5-2.5 Oe; the bias current is provided by a Helmholtz coil when the complete external field GMI data of the bias current is tested; the diameter of the amorphous fiber is 50 +/-1 mu m, and the series matching impedance is 50 omega. The bias current in the present invention is a means of increasing performance, and the external force is an additional applied excitation field for sustained application.

The Co-based amorphous fiber is prepared by adopting a melt drawing method, wherein the vacuum degree is 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 mother alloy for drawing melt is prepared in vacuum magnetic controlled tungsten electrode arc furnace and the main process includes the following steps: 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 argon (Ar, 99.97%) was charged 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. Wherein the amorphous fiber alloy component is Co_68.15Fe_4.35Si_12.25B_13.25Zr₂。

Placing the smelted master alloy bar stock inAnd in the BN crucible, the distance and the placing position between the crucible and the roller are well adjusted. 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 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 wheel 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 master alloy to feed, and preparing the amorphous fiber by using the tip edge of the rapidly rotating copper roller wheel. The following examples of the invention are directed to Co prepared by the melt drawing method_68.15Fe_4.35Si_12.25B_13.25Zr₂The amorphous fiber is applied with a bias current to achieve an improvement in the impedance performance, and the embodiment of the present invention will be described later in detail with reference to the accompanying drawings.

Comparative example 1 preparation of Co by melt Czochralski method_68.15Fe_4.35Si_12.25B_13.25Zr₂Amorphous fiber, the diameter of which is about 50 μm, the roundness is high, and the surface is smooth. The high-frequency impedance analyzer HP4192 is used for connecting fibers by adopting a two-end method, the PASCO multifunctional current source is connected to a fiber testing end in parallel, and bias current is provided and comprises sine wave alternating current, rectangular square wave alternating current and triangular wave alternating current, the change of the current amplitude is the same as that shown in a) in figure 2, the change range is 0mA-60mA, and the frequency is 0-4 MHz. The external excitation magnetic field is provided by a ferromagnet when the impedance performance change is monitored in real time, the size of the external excitation magnetic field is adjusted through distance, and in the comparative example, the application period of the external excitation magnetic field is 2min, and the size of the external excitation magnetic field is 2.5 Oe; the bias current is provided by a Helmholtz coil when the complete external field GMI data of the bias current is tested; the fiber diameter is about 50 + -1 μm, and the series matching impedance is 50 Ω. And then detecting the changes of the impedance, the resistance and the inductive reactance after the bias current is annealed.

Hereinafter, the method of supplying Co-based amorphous fiber by applying a bias current according to the present invention will be described in detail, in which the bias current is direct current.