一引言磁路中所用的材料,約可分爲兩類:一類是磁性软的材料,它的磁滞損失要小,饱和磁化强度要大,磁導率須高。這種材料用在通路者如(?)壓器、鐵心電感等:用在斷路中者如電磁鐵等。另一類是磁性硬的材料,它的頑磁感應强度和矯頑力愈大愈好,就是制造永磁鐵的材料,本文所要討論的。近年來因航空、電訊和其他精密儀器上的需要,永磁鐵材料的改進和發明,日新月 I. INTRODUCTION The materials used in the magnetic circuit can be roughly divided into two types: one is a magnetic soft material, the hysteresis loss is small, the saturation magnetization is large, and the permeability is high. This material is used in the accessor such as (?) Pressure device, such as iron core inductor: used in circuit breakers, such as electromagnets. The other is a magnetic hard material, its coercive induction and coercive strength, the greater the better, is the manufacture of permanent magnet materials, to be discussed in this article. In recent years due to the needs of aerospace, telecommunications and other precision instruments, the improvement and invention of permanent magnet materials, the crescent