Phase equilibria at 1150°C in the Co-rich alloys SmCoZr and structure of the 1:7 phase

Abstract In the concentration range 75–100 at.% Co, the isothermal section at 1150°C of the system SmCoZr is determined experimentally. The following features are evidenced: a very small Sm solubility in Co, Zr 2 Co 11 , and Zr 6 Co 23 , an extended Zr for Sm substitution rate in SmCo 3 , Sm 2 Co 7 and Sm 5 Co 19 , and a significant Zr solubility in SmCo 5 and Sm 2 Co 17 that induces the existence of a continuous ternary single phase 1:7. On the basis of the lattice parameter data, the formation of this phase by the substitution of Co dumbbells and/or Sm atoms for Zr atoms is proposed.