RU1790008C - Method of tuning and temperature stabilization of magnetic periodic focusing systems with permanent magnets based on rare-earth metals - Google Patents

Abstract

The invention relates to methods for tuning and stabilizing magnetic periodic focusing systems operating at elevated temperatures and used in instrumentation. The aim of the invention is to increase the stability of the system, reduce the setup time and the consumption of magnets. The necessary level of magnetic properties is achieved as a result of two-stage magnetic processing, including demagnetization by a negative magnetic field to a magnetic induction value less than the required value and magnetization by a positive magnetic field of 400-720 kA / m. 3 tab. ate with

Description

The invention relates to electrical engineering, in particular to methods for tuning and stabilizing magnetic periodic focusing systems (MPFS) operating at elevated temperatures and used in instrumentation.

A known method for tuning MPFS, including demagnetization of permanent magnets with an alternating magnetic field with decreasing amplitude.

However, this method is not applicable to modern magnetic materials characterized by high values of magnetic induction and high coercive force. In addition, with this method of demagnetization, the required magnetic state is achieved due to weakly coercive microvolumes that are least resistant to temperature.

Closest to the proposed one is a method for setting MPFS, including individual demagnetization of ring-shaped, pre-stabilized permanent magnets to the required value of residual induction by a negative magnetic field, assembling of a magnetic system from them, stabilization of this system at 140 ° C for 1 h and subsequent control of magnetic system parameters.

The disadvantage of this method is the use of a field opposite to the initial magnetization direction of the ring magnets when demagnetizing the magnets. When controlling VJ

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After the magnetic properties, after temperature stabilization of some ring magnets, a significant deviation (± 3 mT) from the required level is detected, which necessitates their replacement. After such a replacement, it is necessary to re-stabilize the system, which significantly increases the system setup time and leads to an increase in the material part of the magnets that must be disposed of) and labor costs.

The aim of the invention is to increase the stability of the system, reduce the setup time and the consumption of magnets.

Example. K.18 × 10 × 4 stabilized SmCos magnets were demagnetized by a reverse magnetic field to a residual induction in the center of the ring of 78 ± 3 mT (the measurement was carried out on a MIRT-1 device with an accuracy of ± 1%), after which the system was stabilized for 1 h at 140 ° C, and then again measured the induction in the center of the rings.

The results of measurements of the magnetic properties of the rings carried out at the UFI facility with an accuracy of ± 2%, and measurements of induction in MPFS are given in Table. 1.

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From the results given in table. It follows from Fig. 1 that in the case when the coercive on the ring force is 1440 kA / m, an increase in induction of 3 mT is observed, which exceeds the requirements presented in MPPS.

In the event that the stabilized K18x10x4 magnets are subjected to magnetic treatment according to the proposed method, followed by stabilization at 140 ° C for 1 h, the picture will change significantly (see Table 2). The measurements used the same magnets as in the first case.

In the table. Figure 3 shows the data for Nd - Dy - Fe - B magnets.

From the measurement results shown in table. 2 and 3, it can be seen that in the case where the magnitude of the magnetizing field is within the limits of the invention, i.e. 400-720 kA / m, all magnets meet the requirements for deviation of the magnetic induction from the nominal value of 78 ± 3 mT. With a special selection of gender F, the deviation is zero. If you go beyond the proposed values according to the invention, part of the magnets must be replaced.

Claims (1)

SUMMARY OF THE INVENTION Method of tuning and temperature stabilization of magnetic periodic focusing systems of permanent magnets based on compounds of rare-earth metals with Sd metals, including demagnetization of pre-stabilized magnets, assembly of the system and its temperature stabilization, characterized in that, for the purpose of To increase the stability of the system, reduce the time of its adjustment and the consumption of magnets, demagnetize pre-stabilized magnets by demagnetizing with a negative magnetic field to a magnetic induction value less than the required value, and then magnetizing with a positive magnetic field of magnitude 400-720 kA / m. Magnetic properties of K18 x 10 x 4 rings and MPFS after demagnetization by a reverse magnetic field and stabilization Note. The demagnetization curves of all rings except N 3 have a high degree of rectangular ™. Table 2 Properties of MPPS after magnetic treatment in accordance with the invention and temperature stabilization (140 ° C. 1 h) Note. In samples 5-10, the deviation of induction after temperature stabilization was 0.5 mT, which is less than the measurement error; 2 - Hi - 680 kA / m; 3-W-480kA / m: 4 — Examples in columns 2, 3, and 10. 11 are outside the scope of the invention. Table 1 Table 3 Properties of MPPS from magnets of the Nd - Dy - Fe - B system after demagnetization and stabilization (K18 x 10 x 4 mm rings)