Sintered Anisotropic NdFeB Magnets Fabricated by a Powder Injection Molding Approach

摘要

In this work powder injection molding (PIM) process was applied to fabricate anisotropic sintered Nd-Fe-B magnets. PIM is an alternative process that allows production of magnets with intricate shapes, small dimensions and high productivity. The experimental of this study consisted in preparing samples with a multi-component binder system, designed to be removed in several steps, in order to provide shape retention during this process. Injection molding was performed under magnetic field, in a specially designed mold. Injected samples were chemically and thermically debound and hydrogen flux was employed as a reducing agent for carbon removal during thermal debinding. Sintered samples were characterized in terms of magnetic properties, microstructure, density, and residual carbon. Results show that with PIM process is possible to reach values of remanence of 1T and 1100 kA/m of coercivity. The feedstock alignment was noticed to be effective based on measurements in the easy and hard directions.