1The Research Institute of Electric and Magnetic Alloys, Yagiyama-minami 2, Sendai
Measurements of the magnetic properties, the thermal expansion, the electrical resistivity and the hardness were carried out for Fe-0--3 mass%Nb-4--0 mass%Ta-20 mass%Co-3 mass%Mo allays. All the alloys used in this study were water-quenched from 1323 K, cold-drawn to 97.2% reduction in area and subsequently reheated at 673--1273 K for the period less than 18 ks. The magnetic properties of alloys depend remarkably on the contents of niobium and tantalum, and the reheating temperature and time.
When water-quenched, cold-drawn and subsequently reheated at 973 K for 1.8 ks, an Fe-1.5%Nb-1.5%Ta-20%Co-3%Mo alloy exhibits the following values: B8 at 8 kA•m-1=1.96 T, Br=1.86 T, Br/B8=0.95, Hc=1.89 kA•m-1, \sqrt(BH)max/BrHc=0.95, the mean thermal expansion coefficient α T at 273--313 K=9.0×10-6 K-1, the electrical resistivity ρ =0.262 μ Ω •m and Vickers hardness Hv=391. Also, using ferro-niobium for metallic niobium as raw material, an Fe-1.5%Nb-0.5%Ta-20%Co-3%Mo alloy reheated at 1023 K for 0.6 ks exhibits the following values: B8=2.00 T, Br=1.86 T, Br/B8=0.95, Hc=1.75 kA•m-1, \sqrt(BH)max/BrHc=0.95, α T=8.8×10-6 K-1, ρ =0.265 μ Ω •m and Hv=444.
Thus the Fe-Nb-Ta-Co-Mo alloys ``Recalloy'' is practically suitable to the reed blade in remanent reed switch. Further, there is such a big merit that the expensive cobalt content in Recalloy is 1/2--1/4 as compared with that of semihard magnetic materials having most practical use.
semihard magnetic alloy, iron based-alloy, Recalloy, rectangular magnetic hysteresis, remanent reed switch, thermal expansion, electrical resistivity, hardness, precipitation, fiber texture
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