Device and method for measuring magnetism of permanent magnet material at high temperature

Patent metadata

Field	Value
Publication number	US-2023273274-A1
Application number	US-202118016365-A
Country	US
Kind code	A1
Filing date	Apr 16, 2021
Priority date	Apr 9, 2021
Publication date	Aug 31, 2023
Grant date	—

Abstract

A device for measuring magnetism of a permanent magnet material at a high temperature includes a laser device, a power controller, a light beam controller, a temperature controller, a magnetism measurement unit, temperature sensors, and electromagnet pole heads. The electromagnet pole heads are divided into an upper piece and a lower piece for clamping upper and lower surfaces of a sample. Heat absorbing sheets are respectively fixed on front and rear surfaces of the sample. Temperatures of the heat absorbing sheets are measured by the temperature sensors. The sample is heated by laser, and the temperature controller is used to adjust a ratio of light beams of the power controller and the light beam controller irradiating the heat absorbing sheets on the front and rear surfaces of the sample, thus adjusting the temperatures of the heat absorbing sheets. The magnetism of the sample is measured using the magnetism measurement unit.

First claim

What is claimed is:

1 . A device for measuring a magnetism of a permanent magnet material at a high temperature, comprising a laser device, a power controller, a light beam controller, a temperature controller, a magnetism measurement unit, temperature sensors, and electromagnet pole heads, wherein the electromagnet pole heads are divided into an upper piece and a lower piece, wherein the upper piece clamps an upper surface of a sample and the lower piece clamps a lower surface of the sample; heat absorbing sheets are respectively fixed on a front surface and a rear surface of the sample;
wherein the temperature sensors are arranged on the heat absorbing sheets and measure a temperature of the heat absorbing sheets; wherein the magnetism measurement unit is connected with a magnetic field measurement probe and a magnetic induction intensity measurement coil and the magnetism measurement unit records and calculates a magnetism of the sample, wherein the magnetic field measurement probe is arranged on a side surface of the sample, and the magnetic induction intensity measurement coil is arranged at a bottom of the sample; wherein the laser device emits a laser beam, and the laser beam is divided into two laser beams by the light beam controller to irradiate the front surface and the rear surface of the sample, thereby heating the sample; and wherein the temperature controller is connected with the light beam controller, the power controller and the heat absorbing sheets, and the temperature controller adjusts a ratio of light beams of the light beam controller and light beams of the power controller irradiating the heat absorbing sheets on the front surface and the rear surface of the sample thereby adjusting the temperatures of the heat absorbing sheets.

2 . The device according to claim 1 , wherein each of the heat absorbing sheets is made of a high-temperature-resistant heat conduction material with a thickness of 1 mm to 5 mm, and a surface of each of the heat absorbing sheets is coated with a heat absorbing film having a wavelength consistent with a wavelength of the laser; and the heat absorbing sheets are fixed on the front surface and the rear surface of the sample by clamps.

3 . The device according to claim 1 , wherein the heat absorbing sheets are fixed on the front surface and the rear surface of the sample through high-temperature heat conduction glue.

4 . The device according to claim 1 , wherein a heat isolation sheet is arranged between each of the electromagnet pole heads and the sample.

5 . The device according to claim 1 , wherein the power controller is an adjustable electric light filter with a light filtering efficiency of 0.1%-100%, and the power controller is preferably an electric light filter rotating wheel; the light beam controller is an adjustable light beam controller comprising a reflector and a light filter, and a reflected light beam is adjustable within 1%-100%; each of the temperature sensors has an operating temperature of 0° C.-900° C., and the temperature sensors are arranged inside or on the front surface or the rear surface of the heat absorbing sheets.

6 . The device according to claim 1 , wherein the sample has a length, a width and a height of a, b and c respectively, wherein the height c has a value of 5 mm≤c≤20 mm; and the length and the width have values of 5 mm≤a≤10 mm and 5 mm≤b≤10 mm respectively.

7 . A method for measuring a magnetism of a permanent magnet material comprising using the device according to claim 1 , comprising the following steps:
step I: magnetizing a square block permanent magnet sample to a saturated state; step II: fixing two heat absorbing sheets on a front surface and a rear surface of the square block permanent magnet sample and placing the square block permanent magnet sample between two electromagnet pole heads, and adjusting a distance between the electromagnet pole heads to allow the two electromagnet pole heads to compress the square block permanent magnet sample; step III: emitting, by the laser device, a laser beam, wherein the laser beam is divided into two laser beams through the power controller and the light beam controller, wherein the two laser beams irradiate the heat absorbing sheets on the front surface and the rear surface of the square block permanent magnet sample, and measuring and obtaining temperatures T 1 and T 2 of each of the heat absorbing sheets on the front surface and the rear surface of the square block permanent magnet sample through temperature sensors on the heat absorbing sheets; step IV: according to the temperatures of each of the heat absorbing sheets obtained in step III, using the temperature controller to adjust the power controller and the light beam controller to allow the temperatures T 1 and T 2 of each of the heat absorbing sheets to gradually approach a temperature T 0 , to finally achieve T 1 =T 2 =T 0 , wherein the temperature controller measures the magnetism of the square block permanent magnet sample after the temperature is stabilized for a period of time; step V: making a magnetizing current to the electromagnet and magnetizing the square block permanent magnet sample to a saturated state; decreasing the magnetizing current, changing a direction of the magnetizing current, increasing the magnetizing current until a demagnetization curve passes through a coercive force point or an intrinsic coercive force point, and measuring, by the magnetic field measurement probe, a magnetic field intensity of the electromagnet in a whole process, and measuring, by the magnetic induction intensity measurement coil, the magnetic induction intensity of the square block permanent magnet sample in the whole process; and step VI: recording and calculating, by the magnetism measurement unit, a demagnetization curve, a maximum BH product, a remanence, a coercive force and an intrinsic coercive force of the square block permanent magnet sample at temperature T 0 .

8 . The method according to claim 7 , wherein a height of a magnetic field magnetizing the square block permanent magnet sample in step I is 1 to 5 times the height c of the square block permanent magnet sample.

9 . The method according to claim 7 , wherein the laser device in step III is a femtosecond pulse laser device or a continuous laser device.

10 . The method according to claim 7 , wherein T 1 and T 2 in step IV are controlled to be T 0 ±2° C., a temperature range of T 0 is 50° C.≤T 0 ≤700° C., and a period of time is 15 min to 60 min.

11 . The method according to claim 7 , wherein in the device, each of the heat absorbing sheets is made of a high-temperature-resistant heat conduction material with a thickness of 1 mm to 5 mm, and a surface of each of the heat absorbing sheets is coated with a heat absorbing film having a wavelength consistent with a wavelength of the laser; and the heat absorbing sheets are fixed on the front surface and the rear surface of the sample by clamps.

12 . The method according to claim 7 , wherein in the device, the heat absorbing sheets are fixed on the front surface and the rear surface of the sample through high-temperature heat conduction glue.

13 . The method according to claim 7 , wherein in the device, a heat isolation sheet is arranged between each of the electromagnet pole heads and the sample.

14 . The method according to claim 7 , wherein in the device, the power controller is an adjustable electric light filter with a light filtering efficiency of 0.1%-100%, and the power controller is preferably an electric light filter rotating wheel; the light beam controller is an adjustable light beam controller co

Assignees

• Univ Jiliang China

Inventors

• Wu Qiong
• Yang Hangfu
• Ge Hongliang
• Yu Nengjun
• Pan Minxiang
• Huang Xiani
• Wang Zisheng

Classifications

• G01R33/14 Primary

  Measuring or plotting hysteresis curves {(G01R33/1207 takes precedence)} · CPC title

• G01R33/1215

  Measuring magnetisation; Particular magnetometers therefor (G01R33/14 takes precedence; electrodynamic magnetometers G01R33/028) · CPC title

• G01R33/007 Primary

  Environmental aspects, e.g. temperature variations, radiation, stray fields (G01R33/025 takes precedence) · CPC title

• G01R33/02

  Measuring direction or magnitude of magnetic fields or magnetic flux (G01R33/20 takes precedence) · CPC title

• G01R33/12 Primary

  Measuring magnetic properties of articles or specimens of solids or fluids (involving magnetic resonance G01R33/20) · CPC title