Improved corrosion resistance and thermal stability of sintered Nd-Fe-B magnets with holmium substitution

With increasing Ho substitution the grain boundary was altered and (Nd,Ho)-O phase is formed. The corrosion resistance is improved due to the increased electrode potential of the RE-rich phases by the more stable (Nd,Ho)-O phase. And the temperature coefficients for both remanence and coercivity are all improved with increasing Ho substitution. The coercivity variation with increasing Ho substitution is caused by the microstructure featuring the (Nd,Ho)-O phase in the Ho-substituted magnets.228