Lanthanum-containing Ternary Solid Solutions with the NaZn13-, ThMn12- and Th2Zn17-Type Crystal Structures

Phase equilibria and extensions of solid solutions based on the binary La-phases of the NaZn , ThMn , and Th Zn structure types in several ternary systems are described. In the La–Fe –Al system, besides the ternary phases with the above given structure types, three other ternary phases of unresolved structures are obtained at compositions La Fe Al , LaFe Al and La Fe Al . The phase LaCo (NaZn ) dissolves up to 5.5 atoms of Fe per formula unit in place of Co leading to a steady increase of lattice parameter. Ternary phases with unresolved crystal structures are encountered in the La–Co –Fe alloys, one near LaCo and another near the 2:17 stoichiometry. Likewise, LaCo dissolves up to 3 atoms of Al per formula unit in place of Co. However, it dissolves very little,