The microstructure of Mn-Sn-N and Mn-Sn-Co-N alloys was investigated by scanning electron microscopy and transmission electron microscopy (TEM). After the Mn-Sn alloy was annealed at 1000 °C under nitrogen, the coercivity increased to 245 kA m-1 and a lamellar structure appeared. The TEM images showed that the lamellar structure contained twins in the perovskite-type phase. After the Mn-Sn-Co alloy was annealed at 900 °C and subsequently annealed at 500 °C under nitrogen, the coercivity increased dramatically to 1270 kA m-1. A fine two-phase structure consisting of β-Mn and perovskite-type phases was observed, and some twins were present in the perovskite-type phases. In addition, a higher twin density was observed in the Mn-Sn-Co-N alloy than in the Mn-Sn-N alloy. These results indicate that the twins increased the coercivity of nitrided Mn-Sn based alloys.
- Transition metal alloys and compounds
- Transmission electron microscopy
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry