Abstract
Phase formation in the solid solution TbNiIn1−x
Ga
x
at 873 K was investigated in the full concentration range by means of powder X-ray diffraction and EDX analysis. The samples were synthesized by arc-melting of the pure metals with subsequent annealing at 873 K for one month. The influence of the substitution of indium by gallium on the type of structure and solubility was studied. The solubility ranges have been determined and changes of the unit cell parameters were calculated on the basis of powder X-ray diffraction data: TbNiIn1–0.4Ga0–0.6 (ZrNiAl-type structure, space group
P
6
‾
2
m
$P‾{6}2m$
, a = 0.74461(8)–0.72711(17) and c = 0.37976(5)–0.37469(8) nm); TbNiIn0.2–0Ga0.8–1.0 (TiNiSi-type structure, space group Pnma, а = 0.68950(11)–0.68830(12), b = 0.43053(9)–0.42974(6), с = 0.74186(10)–0.73486(13) nm). The crystal structures of TbNiGa (TiNiSi type, Pnma, a = 0.69140(5), b = 0.43047(7), c = 0.73553(8) nm, wR2=0.0414, 525 F
2 values, 21 variables), TbNiIn0.83(1)Ga0.17(1) (ZrNiAl type,
P
6
‾
2
m
$P‾{6}2m$
, a = 0.74043(6), c = 0.37789(3) nm, wR2 = 0.0293, 322 F
2 values, 16 variables) and TbNiIn0.12(2)Ga0.88(2) (TiNiSi type, Pnma, a = 0.69124(6), b = 0.43134(9), c = 0.74232(11) nm, wR2 = 0.0495, 516 F
2 values, 21 variables) have been determined. The characteristics of the solid solutions and the variations of the unit cell parameters are briefly discussed.
Metastable Solid Solution with Nepheline-type Structure in the CaO–Al2O3–SiO2System
