Effects of Phosphorus Addition on the Magnetic Properties of Sintered Fe-50 wt. percent Ni Alloys

摘要

Phosphorus was added to Fe-50 wt. percent Ni in the form of coated composite power via an electroless plating process. Addition of phosphorus to Fe-50 wt. percent Ni facilitated increases in density and grain size, both of which were beneficial to magnetic performance. Because of the homogeneous distribution of phosphorus in the powder, the optimal phosphorus addition was much lower than for those using Fe_3P as the phosphorus precursor. The optimal phosphorus addition was close to its maximum solubility in Fe-50 wt. percent Ni (about 0.5 wt. percent), above which precipitation of excessive phosphorus in the form of iron nickel phosphide, (Fe,Ni)_3P, effectively degraded the magnetic properties of Fe-50 wt. percent Ni. Without the addition of phosphorus, good magnetic properties could be achieved only when the sintering temperature was high enough (>1200 deg C) to result in a high sintered density and large grains in the sintered structure.