Measuring principle of magnetic declination of permanent magnet
At present, in the production process of most magnetic materials, the accuracy and consistency of the material magnetization direction are not critical. However, as the application fields of magnetic materials become wider and wider, the precision of permanent magnets is also getting higher and higher. Compared with the requirements of traditional magnetic materials, new application technologies have more special requirements for the magnetic properties of permanent magnets. Since the final magnetization vector direction (magnetic declination) of permanent magnets has an extremely important impact on the performance of precision magnetic components, permanent magnets The magnetic declination of the magnet is an important index to measure the performance of the permanent magnet.
Measuring principle of magnetic declination of permanent magnet
We know that a single Helmholtz coil can be used to measure the magnetic moment M produced by the permanent magnet's magnetic moment on the magnetization direction axis. The magnetic moment M can be obtained by the relation: M=k×Φ, where: k is the Helmholtz coil constant, and Φ is the magnetic flux induced by the magnet to the coil. For the quality inspection of magnetized permanent magnet material samples, the use of Helmholtz coils for quality transfer between buyers and sellers has become very popular and versatile, and single-dimensional and three-dimensional Helmholtz coils have been designed to participate in It is especially important to pass parameters between peers.
The direction of the magnetic moment of an anisotropic magnet is always along the direction of anisotropy, but the direction of anisotropy may not coincide with the direction of the magnet axis. When it is necessary to display the projection of the anisotropic direction of the magnetic block on the axial direction of the magnetic block itself, a three-axis Helmhaus coil that can simultaneously display the orthogonal magnetic flux Øx, Øy, and Øz is required, and the orthogonal component magnetic flux can be converted Moments Mx, My, Mz.
The magnetic moment M is a vector, which can be divided into three parts in three directions, namely: X, Y, and Z are in the same direction. The projection relations are: cosαx= Mx/M , cosαy = My/M and cosαz= Mz/M.
By measuring the magnetic flux on the three-axis coil: Φx, Φy, Φz, and according to the constants corresponding to each coil, calculate the magnetic moment in three directions: Mx, My, Mz. The total magnetic moment M of the permanent magnetic material can also be obtained by calculating the square and root of each component magnetic moment.
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