Magnetic Properties and Corrosion Characteristics of Nd-(Fe,Co,Ni)-B Pseudo-Ternary System

Melt-spun ribbons and sintered materials with the composition Nd
₁₅
(Fe
_1-x-y
Co
_x
Ni
_y
).
₇₇
B
₈
were investigated with respect to the saturation magnetization, coercivity, Curie temperature and corrosion characteristics. It was found that simultaneous substitution of Co and Ni atoms for Fe atoms enhances the intrinsic coercivity of sintered magnets in the composition range 0.2≤x≤0.4 and 0.0≤y≤0.2, and also improves the corrosion resistance. A further addition of Ti atoms to the system increases the coercivity and makes the demagnetization curve rectangular. For example, the (BH)
_max
and intrinsic coercivity in Nd
₁₅
(Fe
_0.585
Co
_0.30
Ni
_0.10
Ti
_0.015
)
₇₇
B
₈
are as high as 33.8 MGOe and 10.4 kOe respectively.