Structural and magnetic properties of nanocrystalline Zr-Co-Nb-Si-B rare earth free permanent magnets fabricated by spark plasma sintering

摘要

Rare earth free nanocrystalline Zr16Co78-xNbxSi3B3 (x = 0-3) bulk magnets were fabricated from melt spun ribbons with high density by employing spark plasma sintering (SPS) technique. The effect of SPS temperature on structural and magnetic properties was investigated. The hard magnetic Zr2Co11 phase which was present in the as-spun ribbons retained after SPS, indicating no phase decomposition. The magnetic properties were found to depend on consolidation temperature and Nb concentration. Optimum magnetic properties of coercivity of 3.3 kOe with saturation magnetization of 52 emu/g were obtained for x = 1 magnet consolidated at 600 degrees C. SPS magnets display a moderate magnetic texture and the coercivity mechanism is governed by combination of both domain wall pinning and nucleation of reverse domains.