阅读说明：本技术 一种可提高换能效率的磁致伸缩波导丝及其制备方法 (Magnetostrictive waveguide wire capable of improving energy conversion efficiency and preparation method thereof ) 是由 田中山 杨昌群 牛道东 李育特 王现中 郑文轩 唐志峰 陈会明 于 2021-07-14 设计创作，主要内容包括：本发明公开了一种可提高换能效率的磁致伸缩波导丝及其制备方法。本发明中磁致伸缩波导丝包括波导丝和磁致伸缩粉末涂层；磁致伸缩粉末涂层为在波导丝的表面均匀喷涂一层磁致伸缩粉末后形成。其制备方法如下：首先使用丙酮溶液清洗波导丝,将波导丝进行预热,遮挡波导丝的盲区段后,将磁致伸缩粉末均匀喷涂在波导丝的表面后使得在波导丝表面形成磁致伸缩粉末涂层；取下遮挡物,对波导丝进行校直处理后,最终制备获得磁致伸缩波导丝。本发明的磁致伸缩波导丝使高频脉冲电流所产生的周向磁场主要集中于涂层内部,提高了同一激励条件下所激发扭转波的强度,使该扭转波传播至拾波线圈时可输出信噪比更高的感应波形,从而降低了信号处理的难度。(The invention discloses a magnetostrictive waveguide wire capable of improving energy conversion efficiency and a preparation method thereof. The magnetostrictive waveguide wire comprises a waveguide wire and a magnetostrictive powder coating; the magnetostrictive powder coating is formed by uniformly spraying a layer of magnetostrictive powder on the surface of the waveguide wire. The preparation method comprises the following steps: firstly, cleaning a waveguide wire by using an acetone solution, preheating the waveguide wire, and after a blind zone section of the waveguide wire is shielded, uniformly spraying magnetostrictive powder on the surface of the waveguide wire to form a magnetostrictive powder coating on the surface of the waveguide wire; and taking down the shielding object, and straightening the waveguide wire to finally prepare the magnetostrictive waveguide wire. The magnetostrictive wave guide wire of the invention ensures that the circumferential magnetic field generated by high-frequency pulse current is mainly concentrated in the coating, improves the strength of the excited torsional wave under the same excitation condition, and ensures that the induced waveform with higher signal-to-noise ratio can be output when the torsional wave is transmitted to the pick-up coil, thereby reducing the difficulty of signal processing.)

1. The utility model provides a can improve magnetostrictive waveguide silk of transduction efficiency which characterized in that: the magnetostrictive waveguide wire (8) comprises an uncoated waveguide wire (3) and a magnetostrictive powder coating (7); the magnetostrictive powder coating (7) is formed by uniformly spraying a layer of magnetostrictive powder on the surface of the uncoated waveguide wire (3).

2. A magnetostrictive waveguide wire according to claim 1 having improved transduction efficiency, characterized in that: the particle diameter of the magnetostrictive powder is 30-40 um.

3. A magnetostrictive waveguide wire according to claim 1 having improved transduction efficiency, characterized in that: the magnetostrictive powder has a saturated magnetostriction coefficient of at least more than 200 ppm.

4. A magnetostrictive waveguide wire according to claim 1 having improved transduction efficiency, characterized in that: the magnetostrictive powder has an acoustic impedance that is the same as the acoustic impedance of the uncoated wave guide wire (3).

5. A magnetostrictive waveguide wire according to claim 1 having improved transduction efficiency, characterized in that: the thickness of the magnetostrictive powder coating (7) is 3-5 times of the skin depth corresponding to the excitation frequency of the pulse current in the magnetostrictive waveguide wire.

6. The method of claim 1, wherein the method comprises the steps of:

firstly, cleaning an uncoated waveguide wire (3) by using an acetone solution, preheating the uncoated waveguide wire (3) to 50-200 ℃, then shielding blind sections at two ends of the uncoated waveguide wire (3) by using a shielding object, and uniformly spraying magnetostrictive powder on the surface of an effective stroke section of the uncoated waveguide wire (3) by using oxygen fuel spraying equipment to form a magnetostrictive powder coating (7) on the surface of the uncoated waveguide wire (3);

and then, taking down the shielding object, and straightening the uncoated waveguide wire (3) sprayed with the magnetostrictive powder coating (7) to finally prepare the magnetostrictive waveguide wire (8).

7. The method of claim 6, wherein the magnetostrictive waveguide wire with high transduction efficiency comprises: the particle diameter of the magnetostrictive powder is 30-40 um.

8. The method of claim 6, wherein the magnetostrictive waveguide wire with high transduction efficiency comprises: the thickness of the magnetostrictive powder coating (7) is 3-5 times of the skin depth corresponding to the excitation frequency of the pulse current in the magnetostrictive waveguide wire.

9. The method of claim 6, wherein the magnetostrictive waveguide wire with high transduction efficiency comprises: the magnetostrictive powder has an acoustic impedance that is the same as the acoustic impedance of the uncoated wave guide wire (3).

Technical Field

The invention relates to a magnetostrictive waveguide wire in the field of magnetostrictive displacement sensors, in particular to a magnetostrictive waveguide wire capable of improving the transduction efficiency and a preparation method thereof.

Background

The magnetostrictive displacement sensor is a device for measuring the absolute displacement of an object, and is widely applied to the engineering fields needing displacement monitoring, such as petroleum, chemical engineering, water conservancy and the like, due to the advantages of high precision, long service life, no need of periodic calibration and the like.

As one of the core components of the magnetostrictive displacement sensor, the waveguide wire is a common transmission carrier of pulse current and guided wave, and the performance of the sensor is directly influenced by the quality of the performance of the waveguide wire. The waveguide wire is usually formed by cold drawing of magnetostrictive materials, the diameter is generally in the range of 0.5-1.0 mm, the materials are required to have good mechanical properties so as to facilitate processing and shock resistance, a large saturated magnetostrictive coefficient is used for generating a significant widemann effect, a high electromechanical coupling coefficient is used for reducing eddy current and hysteresis loss, and good thermal stability is used for reducing the influence of temperature on the wave velocity of the torsional wave.

Magnetostrictive materials can be broadly classified into metal magnetostrictive materials, ferrite magnetostrictive materials, and rare earth giant magnetostrictive materials. The metal magnetostrictive material has better mechanical property and thermal stability, is convenient to process wires required by the waveguide wire, but has lower saturated magnetostrictive coefficient and electroacoustic conversion efficiency, and is commonly made into the waveguide wire required by the medium-short range magnetostrictive displacement sensor at present. The rare earth giant magnetostrictive material has a large saturated magnetostrictive coefficient and high electromechanical coupling efficiency, but the material has high brittleness, and wires required by the waveguide wire are difficult to process.

At present, the materials of waveguide wires used in magnetostrictive displacement sensors are mainly metal magnetostrictive materials, such as Fe-Ni, Fe-Ga and the like, and can meet the measurement requirements in the middle and short range. However, due to the property of the metal magnetostrictive material, the problem of trade-off between the magnetostrictive coefficient and the mechanical property of the material is faced in a wide-range application occasion, and the attenuation of the torsional wave after the torsional wave is propagated in the waveguide wire for a long distance is large, so that the corresponding output signal of the pickup coil is weak when the pickup coil detects the guided wave, and the signal-to-noise ratio is obviously reduced, thereby increasing the difficulty of signal processing and limiting the further improvement of the effective range of the sensor.

Waveguide wires adopted by a traditional wide-range magnetostrictive displacement sensor meet the requirements of machining and forming, usually magnetostrictive materials with good mechanical properties are selected, the saturated magnetostrictive coefficients corresponding to the materials are small, and the strain capacity of the waveguide wires is small under the same magnetic field intensity. Because the torsional wave generated by excitation is continuously attenuated under the influence of factors such as internal friction, uneven reflection and the like in the propagation process, the guided wave signal received by the pickup coil is weak when the propagation path is long, and the analysis and the processing of subsequent signals are not facilitated.

Disclosure of Invention

In order to overcome the problem that echo signals are weak due to the fact that a single waveguide fiber material is used in a wide-range magnetostrictive displacement sensor at present, the invention provides a magnetostrictive waveguide fiber capable of improving energy conversion efficiency and a preparation method thereof. The invention can ensure that the waveguide wire can keep the good mechanical property of the core part and simultaneously improve the transduction efficiency when the torsional wave is excited under the same excitation condition, so that the pickup coil obtains an induction waveform with higher signal-to-noise ratio through the Villari effect.

Magnetostrictive waveguide wire capable of improving energy conversion efficiency

The magnetostrictive waveguide wire comprises an uncoated waveguide wire and a magnetostrictive powder coating; the magnetostrictive powder coating is formed by uniformly spraying a layer of magnetostrictive powder on the surface of the uncoated waveguide wire.

The particle diameter of the magnetostrictive powder is 30-40 um.

The magnetostrictive powder has a saturated magnetostriction coefficient of at least more than 200 ppm.

The magnetostrictive powder has an acoustic impedance that is the same as that of the uncoated waveguide wire.

The thickness of the magnetostrictive powder coating is 3-5 times of the skin depth corresponding to the excitation frequency of the pulse current in the magnetostrictive waveguide wire.

Second, preparation method of magnetostrictive waveguide wire capable of improving energy conversion efficiency

The method comprises the following steps:

cleaning an uncoated waveguide wire by using an acetone solution, preheating the uncoated waveguide wire to 50-200 ℃, then shielding blind sections at two ends of the uncoated waveguide wire by using a shielding object, and uniformly spraying magnetostrictive powder on the surface of an effective stroke section of the uncoated waveguide wire by using oxygen fuel spraying equipment to form a magnetostrictive powder coating on the surface of the uncoated waveguide wire;

and then, taking down the shielding object, and straightening the uncoated waveguide wire sprayed with the magnetostrictive powder coating to finally prepare the magnetostrictive waveguide wire.

The invention has the beneficial effects that:

the invention uses powder with larger saturated magnetostriction coefficient to be evenly sprayed on the surface of the waveguide wire to form a magnetostrictive powder coating, so that a circumferential magnetic field generated by high-frequency pulse current is mainly concentrated in the coating, the intensity of the excited torsional wave under the same excitation condition is improved, and an induction waveform with higher signal-to-noise ratio can be output when the torsional wave is transmitted to a pickup coil, thereby reducing the difficulty of signal processing.

The preparation method of the invention adopts a cold spraying process, so that a layer of magnetostrictive powder can be uniformly adhered to the surface of the conventional waveguide wire, and the waveguide wire with good core strength and plasticity and high magnetostrictive coefficient on the surface can be processed by the method.

Drawings

FIG. 1 is a schematic length view of a coated waveguide wire according to the present invention;

FIG. 2 is a schematic cross-sectional view of a waveguide wire A-A of the present invention after being spray coated;

FIG. 3 is a schematic structural view of a magnetostrictive displacement sensor using a waveguide wire according to the present invention;

fig. 4 (a) shows a waveform of a torsional wave signal received by the pickup coil before the coating process is performed, and fig. 4 (b) shows a waveform of a torsional wave signal received by the pickup coil after the coating process is performed;

in the figure, 1-pick-up coil, 2-moving magnetic ring, 3-uncoated waveguide filament, 4-magnetostrictive strip, 5-signal processing unit, 6-damping element, 7-magnetostrictive powder coating, 8-magnetostrictive waveguide filament.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, a magnetostrictive waveguide wire 8 of the present invention comprises an uncoated waveguide wire 3 and a magnetostrictive powder coating layer 7; the magnetostrictive powder coating 7 is formed by uniformly spraying a layer of magnetostrictive powder on the surface of the uncoated waveguide wire 3 with better strength and plasticity.

The particle diameter of the magnetostrictive powder is 30-40 um.

The magnetostrictive powder has a saturated magnetostriction coefficient of at least more than 200 ppm.

The acoustic impedance of the magnetostrictive powder is the same as that of the uncoated wave guide wire 3.

The thickness of the magnetostrictive powder coating 7 is 3-5 times of the skin depth corresponding to the excitation frequency of the pulse current in the magnetostrictive waveguide wire.

The preparation method of the magnetostrictive waveguide wire comprises the following steps:

firstly, cleaning an uncoated waveguide wire 3 to be treated by using an acetone solution, preheating the uncoated waveguide wire 3 to 50-200 ℃, then shielding blind sections at two ends of the uncoated waveguide wire 3 by using a shielding object, and uniformly spraying granular magnetostrictive powder on the surface of an effective stroke section of the uncoated waveguide wire 3 by using high-pressure high-speed oxygen fuel spraying equipment to form a magnetostrictive powder coating 7 on the surface of the uncoated waveguide wire 3; the uncoated waveguide wire 3 is divided into blind zone sections at two ends and an effective stroke section in the middle.

Then, the shielding object is taken down, and the uncoated waveguide wire 3 sprayed with the magnetostrictive powder coating 7 is straightened to finally prepare the magnetostrictive waveguide wire 8.

One embodiment is provided below in connection with the present disclosure.

The uncoated waveguide wire 3 is made of Fe-Ni alloy and has a diameter of 1 mm. The magnetostrictive powder used for spraying is Fe-Ga alloy powder, the diameter of the magnetostrictive powder is 30-40 um, and the thickness of the magnetostrictive powder coating 7 is about 200 um.

As shown in fig. 3, the magnetostrictive waveguide wire 8 is installed in a magnetostrictive displacement sensor, which mainly consists of a pickup coil 1, a movable magnetic ring 2, a magnetostrictive waveguide wire 8, a magnetostrictive strip 4, a signal processing unit 5 and a damping element 6;

the two ends of the magnetostrictive waveguide wire 8 are respectively sleeved with a damping element 6, the magnetostrictive strip 4 is fixed on the surface of the magnetostrictive waveguide wire 8 through a welding process, the movable magnetic ring 2 penetrates through the magnetostrictive waveguide wire 8, and the movable magnetic ring 2 moves along the magnetostrictive waveguide wire 8 in an effective stroke section of the magnetostrictive waveguide wire 8; the middle part of the magnetostrictive strip 4 is fixedly sleeved with a pickup coil 1, and a signal processing unit 5 is electrically connected with the pickup coil 1.

The working principle of the invention is as follows:

the movable magnetic ring magnetizes the magnetostrictive waveguide wire 8 and forms a static axial magnetic field inside the magnetostrictive waveguide wire 8. When pulse current with higher frequency is introduced into the waveguide wire, due to the action of skin effect, the generated instantaneous circumferential magnetic field is mainly concentrated in the powder coating with larger magnetostriction coefficient, and after encountering an axial magnetic field, the instantaneous circumferential magnetic field excites torsional waves through the Wednman effect and propagates to two ends at a certain speed. When the guided wave signal propagates to the pick-up coil, a corresponding voltage signal is generated in the pick-up coil by the vilari effect. The invention adopts the powder with larger saturated magnetostriction coefficient to be sprayed on the surface of the waveguide wire, so that the waveguide wire can increase the strain caused by magnetostriction while keeping the good mechanical property of the core part, thereby effectively improving the energy conversion efficiency of the excited guided wave.

As shown in fig. 4 (a) and 4 (b), the movable magnetic ring is in the same position and maintained at the same excitation condition, and the amplitude of the torsional wave signal received by the pick-up coil when the waveguide wire is not coated is about 1.4V, while the amplitude of the signal is about 3.2V in the coated condition. The results show that after the wave guide wire is subjected to powder spraying treatment, the pick-up coil can obtain an induction waveform with a higher signal-to-noise ratio when the torsional wave arrives, and subsequent treatment and analysis are facilitated.