Research on High Performance Nd-Fe-B Magnets

Abstract

Effects of the constituent phase of Nd-Fe-B magnets on sintering behavior are investigated. In the case of Nd-Fe-B magnets, a liquid phase forms by ternary eutectic reaction of Nd2Fe14B, Nd1.1Fe4B4 and Nd-rich phase at 938K. When sintering temperature is raised above 1,273K, a remarkable shrinking occures because of an increase in the amount of a liquid phase which is supplied by a reaction between Nd2Fe14B and Nd1.1Fe4B4 phase. The residual flux density (Br) of Nd-Fe-B magnets increases in proportion to the increase in the amount of the Nd2Fe14B phase. On Fe4B4 and the Nd-rich phase. As a result, new high-performance Nd-Fe-B magnets having the maximum energy product of above 366kJ/m3 (46 MGOe) has been developed by means of controlling the component ratios of these phases in Nd-Fe-B magnets.