Stepping motor and method of manufacturing hard magnetic alloy therefor

摘要

In a stepping motor having a stator provided with an electromagnet and a rotor composed of a hard magnetic alloy, the hard magnetic alloy comprises at least one element T of Fe and Co, at least one element R of rare earth elements and B, has a remanence ratio of at least 0.7, remanent magnetization (Ir) of at least 120 emu/g and coercive force (iHc) of at least 1 kOe and includes a fine crystalline phase having an average crystal grain size of 100 nm or less as a main phase. The hard magnetic alloy is solidified and compacted by making use of a softening phenomenon which arises when the amorphous phase contained in the structure of the hard magnetic alloy is crystallized. A method of manufacturing the hard magnetic alloy used to the stepping motor is also disclosed.