Synthesis of metastable Bi6Ti5WO22 phase by the mechanochemical method

Abstract

Mechanochemical processing has been demonstrated as a powerful tool for preparing metastable phases. In this work we have successfully applied it to synthesize a novel Bi6Ti5WO22 phase belonging to the Bi2O3-TiO2-WO3 ternary system. Attempts to obtain this phase by a solid state reaction method as well as by chemical precipitation have failed, confirming that cubic Bi6Ti5WO22 shows a metastable nature. The employ of high-energy milling allows a reduction in both the calcination temperature and time required to obtain a crystalline sample (thereby reducing the Bi-losses by vaporization). As a consequence a pure Bi6Ti5WO22 phase has been prepared which remains stable up to temperatures around 800 degrees C.