Magnetic Properties of Sm-Fe-Co System Nitrided Compounds

Experiments were carried out to investigate the effect of cobalt substitution on the magnetic and physical properties of Sm
2
Fe
17
nitrided compounds. Sm
2
(Fe
1-x
Co
x
)
17
nitrided compounds (x=0 to 0.3) were prepared by heat treating fine powders of Sm
2
(Fe
1-x
Co
x
)
17
alloys in N
2
gas at a pressure of 4.9 MPa. X-ray diffraction patterns revealed these nitrided compounds to have a Th
2
Zn
17
-type structure. Sm
2
(Fe
1-x
Co
x
)
17
alloys were observed to absorb the same large amount of nitrogen as Sm
2
Fe
17
alloy. The Curie temperatures of these nitrided compounds increases with increasing Co content, and the lattice constants a and c decrease slightly. The intrinsic coercivity of 652.5 kA/m (8.20 kOe) and Curie temperature of 556°C were achieved for an Sm
2
(Fe
0.8
Co
0.2
)
17
N
3.1
compound.