Magnetic materials play an important role in modern industry. They are used in a wide range of applications and are major components of motors, generators and transformers, but are also found in hard disks, medical devices, etc. It is the wide range of applications that makes it necessary to achieve tolerances in terms of magnetic properties as well as in terms of mechanical properties and corrosion resistance. Hybrid magnets (bonded magnets) are magnets consisting of a magnetic powder and a polymer binder. These materials have the advantages of good mechanical properties and good corrosion resistance.
The master thesis was carried out in connection with a project at Kolektor d.d. The aim of the thesis was to improve the mechanical properties of an existing composite based on NdFeB magnetic powder and a polymer binder polyphenylene sulphide. In order not to deteriorate the magnetic properties, we had to keep the mass ratios between the magnetic powder and the polymer binder.
To achieve this, we decided to add a liquid crystalline polymer to the PPS binder. Two granulates were produced by extrusion, which had the same ratio of magnetic powder to polymer binder, but differed in the proportions of PPS and LCP. The two granulates were injection moulded into samples, which were then analysed for density, magnetic properties, flexural strength and tensile strength, and finally compared with a base material without LCP addition.
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