Highly Anisotropic TbCo 11 Ti: Phase Evolution, Microstructure and Magnetic Properties

ABSTRACT Among the 1:12‐type compounds, TbCo 11 Ti stands out due to its high Curie temperature and pronounced magnetocrystalline anisotropy. However, its magnetic behavior at room temperature and its phase evolution process have not been clearly established. Here, we demonstrate that TbCo 11 Ti exhibits an outstanding anisotropy field ( μ 0 H a = 23.4 T), a high magnetic hardness parameter ( κ = 4.8) at room temperature and a stable saturation magnetization with a small positive temperature coefficient. Thermodynamically, the 1:12 phase is favored within the range of 1273–1473 K, but decomposes into 2:17 and Co‐rich phases at lower temperatures. Twins are generated with the solid‐state phase transformation. Both coercivity and remanence can be improved by decreasing the twin density and the relative volume fraction of twin variants, respectively. These findings provide new insights to the optimization of 1:12‐type permanent magnets.