Effect of additives on the magnetic properties and microstructure of melt spun SmCo6.9Hf0.1M0.1 (M = B, C, Nb, Si, Ti) ribbons

Effect of additives on the magnetic properties, phase evolution, and microstructure of SmCo6.9Hf0.1M0.1 (M = B, C, Nb, Si, and Ti) ribbons by melt spinning technique under sufficient supercooling condition have been investigated. Among those additives, C is the most effective element in refining the grain size of SmCo6.9Hf0.1M0.1 ribbons, from 100-400 nm for ternary ribbons to 30-100 nm for C-containing ribbons. Besides, C addition also induces extremely fine fcc-Co grains (5-10 nm) in the matrix, resulting in the stronger intergranular exchange coupling effect and the improved magnetic properties. The optimal magnetic properties of B-r = 6.9 kG, H-i(c) = 11.8 kOe and (BH)(max) = 10 MGOe could be achieved for SmCo6.8Hf0.1C0.1 nanocomposite ribbons. (C) 2007 Elsevier B.V. All rights reserved.