The influence of ambient gas pressure on the surface quality and magnetic properties of nanocrystalline NdFeB based melt spun ribbons

• Published in: Materials letters 1999, Vol.38 (1), p.33-38
• Main Authors: Yapp, R, Davies, H.A, Leccabue, F, Watts, B.E
• Format: Article
• Language: English
• Subjects: Ambient pressure; Amorphous and nanocrystalline magnetic materials; quasicrystals; Amorphous and quasicrystalline magnetic materials; Applied sciences; Clusters, nanoparticles, and nanocrystalline materials; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Entrapped gas pockets; Exact sciences and technology; Magnetic properties and materials; Melt spinning; Metals. Metallurgy; Nanocrystalline; Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals; NdFeB; Physics; Ribbon surface quality; Structure of solids and liquids; crystallography; Studies of specific magnetic materials
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/S0167-577X(98)00128-1

The melt spinning of a NdFeB alloy of stoichiometric composition was investigated under various ambient gas pressures, from atmospheric pressure, 100 kPa (760 Torr) to vacuum, 0.13 Pa (10 −3 Torr). Gas pockets were observed on the roll contact surface of ribbons produced at pressures close to atmospheric, whilst a reduction in pressure, to 50 kPa (380 Torr) caused the disappearance of the gas pockets. The absence of the gas pockets led to more consistent magnetic properties for the nanocrystalline ribbon.