| Electromagnetic mechanical optical switches are devices that switch light signals,and magnetic materials are played a crucial role in the process of switching.This article has gave a brief introduction to the principle of optical switches and the role of bonded magnets in optical switches.Due to the limited reserves of rare earth elements and the high prices,the development of new composite bonded magnets,reduction of the demand for rare earth elements of high performance permanent magnetic materials,and saving of rare earth materials,scientific and rational development and utilization of rare earth resource has became hot spots in current research.As a market-oriented electromagnetic mechanical optical switch,the demand for bonded magnets is increasing day by day.How to reduce costs,it is necessary to develop a new type of composite bonded magnet,and the dimensional accuracy of the composite bonded magnet is high,and the complex parts can be integrated,processed and low prices.The influence of the distribution and interaction of rare earth magnetic powder and ferrite magnetic powder on the performance of magnets.And explain it from the mechanism.It will provide corresponding theoretical and technical support for the development of superior performance and inexpensive composite bonded magnets.This article starts with the study of the influence of the preparation process on the performance of the magnet,summarizes the influence of the process parameters on the performance of the magnet,and on the other hand,studies the influence of the magnetic particle size,the magnetic powder ratio and the binder on the magnetic properties of the magnet.The effects of injection temperature,injection speed and injection pressure on the properties of bonded magnets in the injection molding process were systematically analyzed.Based on the optimized process,the K51 binder and PPS binder were compared for Sm-Fe-N/ferrite.The effect of the magnetic properties of the oxygen bonded composite bonded magnets shows that the same mass fraction ofPPS or K51 also has a significant effect on the magnetic properties of the anisotropic Sm-Fe-N ferrite composite bonded magnet.The anisotropic Sm-Fe-N composite ferrite bonded magnets bonded with the same mass fraction of PPS have higher Br than the anisotropic Sm-Fe-N ferrite composite bonded magnets with the same mass fraction of K51.The anisotropic Sm-Fe-N ferrite composite bonded magnet bonded by PPS with mass fraction is also higher in coercive force than the anisotropic Sm-Fe-N ferrite composite bonded magnet bonded by the same mass fraction K51.Therefore,compared with K51,4wt% PPS binder has the best magnetic properties and is more suitable for the preparation of high Br coercive bonded magnets.With the same content of PPS in the binder,the Hc and Br of the anisotropic Sm-Fe-N and ferrite composite bonded magnet almost all increase linearly because the ferrite is low Br.Low Hc materials,while Sm-Fe-N are relatively high Br materials with high Hc.After mixing the two in different proportions,with the increase of the mass fraction of Sm-Fe-N magnetic powder,the effect of the scattered magnetic field on the low magnetic ferrite increases,so the total magnetic performance increases.The Sm-Fe-N/ferrite magnetic powder ratio can be adjusted according to the magnetic properties of the product.In addition to binders,addition of compounding agent to Sm-Fe-N and ferrite composite bonded magnets is also crucial.In this paper,KBM-903 and antioxidants were used to surface treat Sm-Fe-N ferrite magnets.It promotes the adhesion of Sm-Fe-N ferrite magnetic powder and PPS,improves the density and mechanical properties of magnets,reduces the oxidation of Sm-Fe-N and ferrite magnetic powder,and improves the injection molding of Sm-Fe-N iron.Magnetic properties of oxygen bonded composite magnets.Scanning electron microscopy was used to observe the distribution and density of magnetic powder. |
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