Effect of Molding Pressure on Structure and Properties of Ring-Shaped Bonded NdFeB Magnet

Abstract

Ring-shaped polymer-bonded magnets (RSMs) were produced from a mixture of an isotropic NdFeB powder, steel use stainless (SUS) powder, and epoxy resins as binders, using a comprehension-molding technique. Morphology of RSM determined by an SEM indicated that inappropriate molding pressure leads surface defect and brings adverse impact on properties of magnets. The research on mechanical properties shows that the maximum tensile strength of 11.4 N was achieved at optimal pressing pressure of 85 kN. Meanwhile, RSM has excellent stability as the critical component of motor and its amount of unbalance is as low as 0.754 mg. Magnetic property in optimal mechanical conditions was also found to be optimum at H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">cj</sub> = 8.42 kA/m and (BH) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> = 31.17 kJ/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> .