| Since its discovery in1983, NdFeB permanent magnetic materials have beendeveloping to an important functional material for its excellent magnetic properties,which is broadly used in some fields such as electrons, communications and traffics,etc. Sintered NdFeB permanent magnetic materials possess the best magneticproperties. However, there are some weaknesses affected the extending of itsapplications. Therefore, focusing on some problems and aiming on increasing thecoercivity and mechanical properties, investigations of sintered NdFeB permanentmagnetic materials have been undertaking and becoming the unsolved technicalproblems. In this paper, the coercivity and mechanical properties of sintered NdFeBpermanent magnetic materials were systematically studied by changing the elementcontents of intergranular phase in sintered NdFeB permanent magnets with usingnanoparticles doping technology. Using the methods of nanoparticles doping andplating penetration, the influence of Nd-rich phase doped with Dy and Tbnanoparticals on the coercivity of samples were investigated. It was found that themodifying nature of grains boundary by heavy rare earth elements doping couldeffectually increase the coercivity of samples, while the remanence without decrease,showing the most of doped HR atoms were at epitaxial layer of matrix phase grainsand in the Nd-rich phase, without entering inside the matrix phase grains. So, themagnetic hardening in epitaxial layer of matrix phase grains was the key factors thatinfluenced the coercive force of samples, of which the best value is of2517.12KA/m.The influence of doping with Dy, Tb, Cu and Al element on the impact toughness andbending strength of samples were investigated using nanoparticles doping to adjustthe element content of Nd-rich phases. The results showed that doping with Cu and Alatoms couldn’t improve the mechanical properties of samples, while doping with rightcontent of Dy or Tb element can significantly affect the mechanical properties ofsamples. |
PDF Full Text Request