HG/T 2347.2-1992 γFe2O3 magnetic powder magnetic properties measurement method
Some standard content:
Chemical Industry Standard of the People's Republic of China
Method for measuring magnetic properties of Y·Fe2O3 magnetic powder
1 Subject content and scope of application
HG/T2347.2-92
This standard specifies the method for measuring the magnetic properties of Y·Fe2O3 magnetic powder. The vibrating sample magnetometer method or BH instrument method can be used. This standard is applicable to the measurement of magnetic properties of Y·Fe2O3 and modified·FeO3 magnetic powder. 2 Terminology
2.1 Magnetic field intensity H
is the axial vector related to the magnetic flux density at any point in the magnetic field. In a magnetic object with a magnetization intensity of M: H-
In an infinitely long solenoid with a sinusoidal alternating current, the peak magnetic field intensity is H=nl. Where μ-vacuum magnetic permeability, =4 yuan×10-H/m; number of turns per unit length;
I-peak magnetization current,
The unit name of the magnetic field intensity is ampere per meter, and the unit symbol is A/m2.2 Magnetic induction intensity (magnetic flux density) B
A divergent axial vector that defines the magnetic field at any point in space. In practical applications, the magnetic flux passing through the unit cross-sectional area of a uniformly magnetized magnet is usually called the magnetic flux density. The unit is Tesla, the unit symbol is T, B
wherein: @-magnetic flux passing through the magnet, Wb; A-cross-sectional area of the magnet: m2
2.3Magnetic flux Φ
Surface integral of magnetic flux density. In uniformly magnetized materials, the magnetic flux is equal to the product of the magnetic induction intensity and the cross-sectional area perpendicular to it. The unit name is Weber, the unit symbol is Wb,
wherein: B-magnetic flux density, T;
cross-sectional area perpendicular to the magnetic induction intensity, m
2.4Magnetic intensity M
loss related to the volume of the material. It is equal to the total unit magnetic moment Zm in the volume divided by the volume VM
Where: M-
Magnetic intensity, the unit name is ampere per meter, the unit symbol is A/m, the Ministry of Chemical Industry of the People's Republic of China approved the standard on June 1, 1992, and implemented on the network mm.brrca.ccm on March 1, 1993
2.5 Saturation magnetization Ms
HG/T2347.2 -
The maximum value of the magnetization intensity that a material can reach at a given temperature. The unit name is ampere per meter, the unit symbol is A/m, 2.6 Specific magnetization.
Magnetic intensity M divided by the density of the material pt. The unit name is ampere square meter per kilogram, the unit symbol is A·m2/kggM
Where: P—-In this standard, it is the tap density of magnetic powder. 2.7 Specific saturation magnetization c
Saturation magnetization Ms divided by the density of the material pt. The unit name is ampere square meter per dry gram, and the unit symbol is A·m2/kg.Ms
Where: The tapping density of Pt material is kg/m.2.8 The coercive force Hc
corresponds to the magnetic field intensity value when the magnetic flux density (magnetization intensity) is zero. This standard adopts MHC in the MH hysteresis loop. The unit name is ampere per meter, and the unit symbol is A/m.
3 Measurement
3.1 Measurement conditions
There shall be no strong magnetic field or other strong electric spark interference around the laboratory. Measurement environment: temperature 15~30℃;
Relative humidity less than 75%
Measurement of magnetizing field:
When measuring .Fe,O, magnetic powder, it should be greater than 320kA/m; when measuring modified Y·FeO, magnetic powder, it should be greater than 480kA/m. 3.2 Vibrating sample magnetometer measurement method
3.2.1 Measurement principle
The measurement principle is shown in Figure 1
Figure 1 Working principle of magnetic field meter
Vibration System;
-reference coil pair:
3 magnetic poles;
4-detection line diagram; 5-amplification system;
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HG/T2347.2-92
The sample is fixed on the sample rod of the vibrating sample magnetometer, and vibrates up and down in the magnetic field between the magnetic poles of the electromagnet at a certain frequency. A pair of detection coils of equal size and number of turns are installed on both sides of the sample rod between the magnetic poles, and the peak value e of the electromotive force induced by the detection coil is proportional to the magnetic moment of the sample.
Requirements for measuring equipment
The comprehensive uncertainty of the instrument shall not exceed 3%.
Pure nickel standard: ~purity 99.995%, temperature 23℃, density 8.90g/cm, specific saturation magnetization 54.56b.
c.Balance: reading accuracy 0.1mg, maximum load 200g. d.Test tube: a non-metallic, non-magnetic cylindrical tube with one end closed, the size is determined according to the specific conditions of the instrument. The mass of the test tube is m (g), the inner diameter is Φ (mm); the length is L (mm)3.2.3 Sample preparation
The magnetic powder to be measured is sieved with a test sieve with an aperture of 500um, dried at 85±2℃ for 2h, and then placed in a desiccator to cool to room temperature. Then put it into the test tube, tap and fill it, so that the ratio of the sample length L to the inner diameter @ is not greater than 1. Weigh the test tube filled with Fe2O magnetic powder to an accuracy of 0.1 mg and calculate the mass of Y·Fe2O magnetic powder m (g) according to formula (1). m=m.
Where: m—mass of test tube, g,
m2—mass of Fe2O magnetic powder added to the test tube, g.3.2.4 Measurement steps
3.2.4.1 Calibration
Use pure metal nickel standard sample to calibrate according to the method described in the instrument.3.2.4.26 Measurement
Fix the sample to be tested on the sample rod to make it vibrate, apply magnetic field until the sample is saturated, and measure the specific saturation magnetization intensity.3.2.4.3 Measurement of Hc
Fix the sample to be tested on the sample rod to make it vibrate, adjust the current of the electromagnet coil, apply magnetic field until the sample is saturated, and then monotonically reduce the magnetization field to zero. Then add a reverse magnetic field to make it zero, and read the magnetic field strength at this time as the coercive force Hc value 3.3BH instrument measurement method
3.3.1 Measurement principle
This method measures the g and Hc values of the sample under an AC 50Hz saturated magnetic field. The measurement principle is shown in Figure 2:C
Figure 2B-H instrument measurement principle diagram
L--solenoid: A-reading device: N, a measuring coil; V-magnetic flux signal; S-integral amplifier; Vn magnetic field signal standard authorization bona.cc3.3.2 Requirements for measuring equipment
a. Solenoid
HG/T2347.2-92
Within the range where the measuring coil is located, the inhomogeneity of the magnetic field of the solenoid is not greater than 1%, and the uncertainty of the magnetic field constant is not greater than 0.5%.
Integrator
Integration accuracy is better than 0.3% wwW.bzxz.Net
c. Readout device A
Accuracy is better than 2%
d. Balance
Reading accuracy is 0.1mg, and the maximum load is 200ge. Standard sample
With the specified Fe, O, magnetic powder mass m (g) and sample length L (mm), the Fc20 magnetic powder standard sample with the specified c, and Hc values under the saturated magnetic field, the uncertainty of which is not greater than 3%. The standard sample must be calibrated regularly by the metrology department. f. Test tube
The test tube is a cylindrical tube made of non-metallic, non-magnetic material with one end closed and uniform inner diameter. The outer diameter is determined by the inner diameter of the BH instrument measurement line. The mass of the test tube is m1, the inner diameter is D, and the length is L. L and D must simultaneously meet the following conditions: L/D ≥ 20
Where: C——Measurement coil length,
3.3.3 Preparation of sample
Same as 3.2.3. Put ·Fe,O, magnetic powder into the test tube to reach the tapping density, measure the sample length L (mm) and the mass of the test tube m (g), and calculate the y·Fe,O, magnetic powder mass m and tapping density ptp,=m/V
Where: V--·F ezO, volume of magnetic powder, cm3.3.4 Measurement steps
3.3.4.1 Calibration
Use standard sample to calibrate the instrument,
3.3.4.2 Measurement
(2)
Put the sample to be measured in the measuring coil, add saturation magnetic field H, read the maximum magnetic flux at this time, and calculate the specific saturation magnetization intensity Q:
Where: L is the length of the sample, mm;
Sample mass, g
Mo is the vacuum permeability, H=4 yuan×107H/m. 3.3.4.3 Measurement of Hc
Put the sample to be measured in the measuring line, add the saturation magnetic field H, and read the magnetization field when the magnetic field on the hysteresis loop passes through zero, which is Hc, the unit is A/m.
3.3.5 Measurement error
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HG/T2347.2-92
Measured by calibration method, the uncertainty of 6, and Hc is not more than 3%.Additional Notes:
This standard was proposed by the Science and Technology Department of the Ministry of Chemical Industry of the People's Republic of China. This standard is managed by the Ministry of Chemical Industry's magnetic recording material standardization technical management unit. This standard was drafted by Ningguo Institute of Mechanical and Electrical Engineering, the First Film Factory of the Ministry of Chemical Industry, and Guangzhou Magnetic Material Chemical Factory. Standard photography network.bsosa.cc All kinds of standard industry information are free to download
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