Eliminating degradation during bonding of gas atomized Nd-Fe-B

While significant progress has been made in improving the hard magnetic properties of Nd-Fe-B powder produced by inert gas atomization, the ability to maintain the hard magnetic properties during low temperature heating, such as that experienced during bonding, has not been previously demonstrated. For all alloys studied, bulk oxidation was the primary degradation mechanism occurring at elevated temperatures (>225°C). In the rare earth rich conventional alloys, reverse domains nucleated from defects located at or near the surface are a significant degradation mechanism which occurs at low temperatures (<225°C) and severely limits bonded magnet performance. In contrast, TiC modified alloys do not experience degradation during bonding at normal bonding temperatures (150°C to 200°C) due to elimination of the surface reversal degradation mechanism. This is due to the better bulk corrosion resistance resulting from the ability to process compositions with reductions in rare earth content coupled with an internal nanocrystalline microstructure which is similar to melt-spun ribbons