Methods to Prevent Risks During the Production of Magnets and Magnetic Materials

Abstract

D.B. De Mooij et al (PHILIPS’ GLOEILAMPENFABRIEKEN N.V. 25,3) have developed a hard-magnetic material having a great crystal anisotropy which comprises only carbon instead of boron and also a comparatively high content of neodymium. This material has the following composition: (RE_1-xNd_x)Fe₁₄C, wherein RE is one or more rare earth metals having an atomic number exceeding 61 (for example Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Lu) and 0.5≤x≤0.80. It has been found that the magnetic properties decrease substantially if x<0.5 or if x>0.8 In all the combinations a carbide having a tetragonal structure is found. The Curie-temperature is between 500 and 600υK. The hard-magnetic materials can be obtained in the conventional manner by fusing starting materials suitable for that purpose succeeded by an annealing treatment in a protective gas or in vacuum.