The Ce-Ni-Si system as a representative of the rare earth-Ni-Si family: Isothermal section and new rare-earth nickel silicides.

The Ce-Ni-Si system has been investigated at 870/1070 K by X-ray and microprobe analyses. The existence of the known compounds, i.e. : Ce 2 Ni 15.8 Si 1.2 (Th 2 Ni 17 -type), Ce 2 Ni 15-14 Si 2-3 (Th 2 Zn 17 -type), CeNi 8.6 Si 2.4 (BaCd 11 -type), CeNi 8.8 Si 4.2 (LaCo 9 Si 4 -type), CeNi 6 Si 6 (CeNi 6 Si 6 -type), CeNi 5 Si 1-0.3 (TbCu 7 -type), CeNi 4 Si (YNi 4 Si-type), CeNi 2 Si 2 (CeGa 2 Al 2 -type), Ce 2 Ni 3 Si 5 (U 2 Co 3 Si 5 -type), Ce 3 Ni 6 Si 2 (Ce 3 Ni 6 Si 2 -type), Ce 3 Ni 4 Si 4 (U 3 Ni 4 Si 4 -type), CeNiSi 2 (CeNiSi 2 -type), ~CeNi 1.3 Si 0.7 (unknown type structure), Ce 6 Ni 7 Si 4 (Pr 6 Ni 7 Si 4 -type), CeNiSi (LaPtSi-type), CeNi 0.8-0.3 Si 1.2-1.7 (AlB 2 -type), ~Ce 2 Ni 2 Si (unknown type structure), ~Ce 4.5 Ni 3.5 Si 2 (unknown type structure), Ce 15 Ni 7 Si 10 (Pr 15 Ni 7 Si 10 -type), Ce 5 Ni 1.85 Si 3 (Ce 5 Ni 1.85 Si 3 -type), Ce 6 Ni 1.4 Si 3.4 (Ce 6 Ni 1.67 Si 3 -type), Ce 7 Ni 2 Si 5 (Ce 7 Ni 2 Si 5 -type) and Ce 3 NiSi 3 (Y 3 NiSi 3 -type) has been confirmed in this section. Moreover, the type structure has been determined for ~Ce 2 Ni 2 Si (Mo 2 NiB 2 -type Ce 2 Ni 2.5 Si 0.5 ) and ~Ce 4.5 Ni 3.5 Si 2 (W 3 CoB 3 -type Ce 3 Ni 3-2.7 Si 1-1.3 ) and new ternary phases Ce 2 Ni 6.25 Si 0.75 (Gd 2 Co 7 -type), CeNi 7-7.6 Si 6-5.4 (GdNi 7 Si 6 -type) and ~Ce 27 Ni 42 Si 31 (unknown type structure) have been identified in this system. Quasi-binary phases, solid solutions, were detected at 870/1070 K for CeNi 5 , CeNi 3 and CeSi 2 ; while no appreciable solubility was observed for the other binary compounds of the Ce-Ni-Si system. As a prolongation of Rare Earth-Ni-Si system’s isostructural rows, LaNi 7 Si 6 and YNi 6.6 Si 6.1 (GdNi 7 Si 6 -type), ScNi 6 Si 6 (YCo 6 Ge 6 -type), NdNi 6 Si 6 (YNi 6 Si 6 -type), {Tb, Ho} 2 Ni 15 Si 2 (Th 2 Zn 17 -type), Nd 2 Ni 2.3 Si 0.7 and Sm 2 Ni 2.2 Si 0.8 (Mo 2 NiB 2 -type), Nd 3 Ni 2.55 Si 1.45 (W 3 CoB 3 -type) and {Tb, Dy} 7 Ni 50 Si 19 (Y 7 Ni 49 Si 20 -type) compounds were synthesized and investigated. Magnetic properties of the CeNi 6 Si 6 , CeNi 7 Si 6 , CeNi 8.8 Si 4.2 , Ce 6 Ni 7 Si 4 , CeNi 5 Si, Ce 2 Ni 2.5 Si 0.5 , Nd 2 Ni 2.3 Si 0.7 and Dy 7 Ni 50 Si 19 compounds have also been investigated and are presented here. [ABSTRACT FROM AUTHOR]