Crystallization conditions of Al2−xMex(WO4)3 (Me=Ga, In, Sc, Y) solid solutions from the systems Na2O-Al2O3-Me2O3-WO3

The temperature and concentration regions of crystallization of Al2−xMex(WO4)3 solid solutions obtained by replacement of Al2O3 by Ga2O3, In2O3, Sc2O3 or Y2O3 in the Na2O-Al2O3-WO3 system have been investigated. The crystallization regions and concentration boundaries of existence of the solutions are found to depend strongly on the nature of the substituting element. Solid solutions containing Sc and In crystallize from high-temperature solutions at a lower concentration compared with that of pure Al2(WO4)3, accompanied by a high-distribution coefficient of the substituting ion. On the other hand, Ga and Y containing solid solutions crystallize from high-temperature solutions at much higher concentrations, the distribution coefficient of the substituting ions being relatively low.