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.: Ce2Ni15.8Si1.2 (Th2Ni17-type), Ce2Ni15-14Si2-3 (Th2Zn17-type), CeNi8.6Si2.4 (BaCd11-type), CeNi8.8Si4.2 (LaCo9Si4-type), CeNi6Si6 (CeNi6Si6-type), CeNi5Si1-0.3 (TbCu7-type), CeNi4Si (YNi4Si-type), CeNi2Si2 (CeGa2Al2-type), Ce2Ni3Si5 (U2Co3Si5-type), Ce3Ni6Si2 (Ce3Ni6Si2-type), Ce3Ni4Si4 (U3Ni4Si4-type), CeNiSi2 (CeNiSi2-type), ~CeNi1.3Si0.7 (unknown type structure), Ce6Ni7Si4 (Pr6Ni7Si4-type), CeNiSi (LaPtSi-type), CeNi0.8-0.3Si1.2-1.7 (AlB2-type), ~Ce2Ni2Si (unknown type structure), ~Ce4.5Ni3.5Si2 (unknown type structure), Ce15Ni7Si10 (Pr15Ni7Si10-type), Ce5Ni1.85Si3 (Ce5Ni1.85Si3-type), Ce6Ni1.4Si3.4 (Ce6Ni1.67Si3-type), Ce7Ni2Si5 (Ce7Ni2Si5-type) and Ce3NiSi3 (Y3NiSi3-type) has been confirmed in this section. Moreover, the type structure has been determined for ~Ce2Ni2Si (Mo2NiB2-type Ce2Ni2.5Si0.5) and ~Ce4.5Ni3.5Si2 (W3CoB3-type Ce3Ni3-2.7Si1-1.3) and new ternary phases Ce2Ni6.25Si0.75 (Gd2Co7-type), CeNi7-7.6Si6-5.4 (GdNi7Si6-type) and ~Ce27Ni42Si31 (unknown type structure) have been identified in this system. Quasi-binary phases, solid solutions, were detected at 870/1070 K for CeNi5, CeNi3 and CeSi2; 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, LaNi7Si6 and YNi6.6Si6.1 (GdNi7Si6-type), ScNi6Si6 (YCo6Ge6-type), NdNi6Si6 (YNi6Si6-type), {Tb, Ho}2Ni15Si2 (Th2Zn17-type), Nd2Ni2.3Si0.7 and Sm2Ni2.2Si0.8 (Mo2NiB2-type), Nd3Ni2.55Si1.45 (W3CoB3-type) and {Tb, Dy}7Ni50Si19 (Y7Ni49Si20-type) compounds were synthesized and investigated. Magnetic properties of the CeNi6Si6, CeNi7Si6, CeNi8.8Si4.2, Ce6Ni7Si4, CeNi5Si, Ce2Ni2.5Si0.5, Nd2Ni2.3Si0.7 and Dy7Ni50Si19 compounds have also been investigated and are presented here.