A Study on Alnico Permanent Magnet Powders Prepared by Atomization

Alnico powders were prepared by gas atomization process. Composition of the Alnico powders was Fe37.1 Al8.2 Ni17.6-Co26.6 Cu3.3 Ti7.2 (wt pct) which was the same as that of commercially available Alnico magnets. Average particle size of the powders was 119μm. Effects of heat treatment in magnetic field on magnetic properties of the powders were investigated. The optimum process of heat treatment was found as follows, heated at 870℃ for 1 min first, then cooled down to 700℃ at cooling rate 0.3℃/s in magnetic field, and finally aged isothermally for 4 h.Magnetic properties of the Alnico powders were measured and the results were that intrinsic coercivity iHc was 1.0kOe and remanence Mr was 36.5 emu/g.