from the conferences organized by TANGER Ltd.
In study the effect of the of Nd-(Fe,Co)-B particles biencapsulation method on bonded magnetic material atmospheric corrosion behavior has been evaluated. Bonded magnets were prepared from Nd12Fe77Co5B6 magnetic powder after biencaspsulation. In this work three kind of biencapsulation method (double layer coating of powder particles) were applied. The powder biencapsulations with bilayers of Ni-P/epoxy resin, phosphate/epoxy resin and Cu/epoxy resin, was carried out to protect the surface of the powder particles against oxidation during manufacturing process. In the paper the results of accelerated gravimetric tests were carried out in so called artificial industrial atmospheres. Experimental conditions of the chosen environments were as follows: aerosol produced from aqueous solution of 3 mg/dm3 SO2, at temperature of 40 °C. The corrosion rates were determined on the basis of sample’s mass gain per surface unit in order to relationship of Δm/S versus time. It has been established that used method of magnetic powder pretreatment satisfactory encapsulates individual particles of the powder and consequently, significantly inhibits corrosion processes of the final material in artificial industrial atmospheres but only in case when used coating layer tightly cover entire particle surface (Ni-P/epoxy resin and phosphate/epoxy resin). There is no improvement in the case of use the encapsulation with Cu/epoxy resin, because the Cu layer does not cover entire surface of powder surface.
Keywords: neodymium magnets, dielectromagnets, biencapsulation, Nd-Fe-B, bonded magnets© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.