Preparation of a continuous series of solid solutions in the Ta2O5--Nb2O5 system

A continuous series of Ta2O5--Nb2O5 solid solutions was obtained by anodically dissolving calculated amounts of tantalum and niobium in a saturated solution of NH4Cl in methanol (at room temperature), evaporation of the solvent, and thermal decomposition of the product at temperatures not exceeding 750 to 8000C. X-ray diffraction analysis showed that at all Ta:Nb ratios the product was isomorphic with β-Ta2O5 (γ-Nb2O5); all reflections could be indexed in an orthorhombic cell, with a increasing linearly from 6.170 to 6.192 A and c decreasing linearly from 3.935 to 3.885 A as Ta was substituted for Nb. The changes in parameter b as a function of composition were less pronounced and its values were between 3.657 and 3.662 A. The method may be used for the preparation of various mixed oxides that are difficult to prepare by other techniques