Twinning structure in Sm(Co,Fe,Cu,Zr)z permanent magnet

Microstructure of the sintered Sm(Co,Fe,Cu,Zr)z magnet was investigated by TEM. Twinning relationships in the rhombohedral Sm2Co17 phase were analyzed. Formation of the twinning is related to the ordered substitution of Sm atoms by Co atomic pairs along different directions in the crystal structure. The atomic structures of twinning were discussed on the base of TEM observation.