Rare earth elements underpin the world’s strongest magnet, but the materials are brittle and frequently break during manufacturing, resulting in significant yield losses. Tough SmCo, from Ames Laboratory and Electron Energy Corp., alleviates brittleness while maintaining magnetic performance through advanced microstructural designs that incorporate bimodal grain size distributions and maintain full compatibility with current magnet manufacturing processes.

Current Nd-Fe-B-based magnets require additions of dysprosium, one of the world’s most critical elements, to function at elevated temperature (>150° C). Sm-Co magnets are more powerful than the Nd-Fe-B-Dy magnets at these temperatures but are very brittle, difficult to machine, and require special systems for safe manufacturing and operation. Researchers at Ames Laboratory discovered that doping the feedstock with small amounts of grain growth inhibitors improves the material’s flexural strength by 70% without noticeable change to magnetic properties. The slight change to the feedstock can be easily integrated with the existing manufacturing processes. Besides reducing chipping and cracking during manufacturing, assembly and operation, this technology enables Sm-Co magnets with odd sizes and shapes for ever more demanding applications.