Effects of Nb and Mo additions on thermal behavior, microstructure and magnetic property of FeCoZrBGe alloy

Both Nb and Mo additions play a vital role in FeCo-based alloys and it is crucial to understand their roles and contents on thermal behavior, microstructural feature and magnetic property of alloys. Nanocrystalline alloy ribbons Fe₄₀Co₄₀Zr_{9 – y}M_yB₁₀Ge₁ (y = 0–4; M = Nb, Mo) were prepared by crystallizing the as-quenched amorphous alloys. The effects of Nb and Mo additions on structures and properties of the Fe₄₀Co₄₀Zr₉B₁₀Ge₁ alloy are investigated systemically and compared. With increasing Nb or Mo content, the primary crystallization temperature, grain size of α-Fe(Co) phase and coercivity H _c all decrease. Moreover, the effect of Mo addition on thermal behavior, microstructure and magnetic properties of the FeCoZrBGe alloy is greater compared to Nb addition. The gap between primary and secondary crystallization peaks of Mo-containing alloys is wider than that of Nb-containing alloys. Both grain size and H _c of Mo-containing alloys are smaller than those of Nb-containing alloys. For Fe₄₀Co₄₀Zr₉B₁₀Ge₁ alloy, high Mo addition proportion is better compared to high Nb addition proportion. (paper)