China is a big country of rare earth resources, rare earth storage ranks first in the world, whether it is SmCo series or NdFeB series rare earth permanent magnet material research and development and application have absolute advantages. With the continuous improvement of the quality requirements of rare earth permanent magnets, controlling the magnetic torque M of rare earth permanent magnet materials and the magnetic declination Angle θz of the main shaft will be of great significance for providing stable magnetic field sources as the core components of rare earth permanent magnet components as sensors.
It can accurately measure the magnetic moment M of axial magnetized rare earth permanent magnet materials and the magnetic declination Angle θz of the main shaft, which can provide great guarantee for the later development of sensors, mainly involving the fields of mobile phone micro-motor magnets, automobile velocity sensor magnets, petroleum exploration magnets, Hall sensor magnets, etc.
The production of high-quality magnetic steel is one of the ways for enterprises to survive and create high profits. At present, users at home and abroad are not only concerned about the BH characteristics of the material, but also about the consistency of the magnetic moment of the material, and whether the magnetic declination Angle of the main shaft is controlled within the allowable range. The demand for such magnetic steel will continue to improve with the design of high-tech permanent magnet circuit devices, and the profit is much higher than that of ordinary magnetic steel. The magnetic moment parameter has gradually become an international test standard for transmission, and the addition of magnetic declination measurement has extremely important significance for the magnetic steel in the inspection of the orientation and cutting of the manufacturing process of the manufacturing enterprise.
2. Research status and development trend at home and abroad
The traditional magnetic moment measurement and magnetic declimation measurement equipment can be traced back to the 1990s, and the "vector magnetic moment test system" produced by LDJ Company (merged by Laboratorio Elettrofisico) and the products of Brockhaus company in Germany have been reported. After 2010, the more outstanding is the new magnetic declination test system designed by German matesy company using magnetoresistance matrix, and domestic enterprises still use the traditional coil method.
The traditional magnetic declination measuring equipment is designed by using fluxmeter and three-dimensional Helmholtz coil, which has simple principle and strong traceability. However, due to the high requirements on fluxmeter and test coil, the requirements on fluxmeter drift control, Helmholtz coil calibration and coil orthogonal installation are high, and because the non-spindle component magnetic moment is very low, the resolution of the fluxmeter is high. These are the problems to be solved to do a good job in traditional magnetic declination test equipment. At the same time, the requirements for the test environment are also high (the environmental magnetic field can not fluctuate).