M. G. Safronenko

Phase formation of BICUVOX solid solutions

Phase formation of Bi4(V1 − xCux)2O11 − z solid solutions (BICUVOX) with x = 0.00–0.20 and Δx = 0.02 was studied. The concentration stability ranges were determined for the α, β, and γ polymorphs of BICUVOX solid solutions at room temperature, and their unit cell parameters were revised. The following was found to occur as x rises: the α ai β phase transition temperature between the monoclinic and orthorhombic phases shifts down, the β ai γ phase transition temperature to the high-temperature tetragonal phase shifts down, and the order-disorder phase transition temperature between γ′ ai γ tetragonal phases shifts up.

Phase formation and physicochemical properties of solid solutions Bi4–yTbyTi3O12 based on layered bismuth titanate

The phase formation of solid solutions Bi4–yTbyTi3O12, where y = 0.0, 0.2, 0.4, 0.6, and 0.8, was studied, and a scheme of this process in an oxide reaction mixture was proposed. The thermal stability of the obtained solid solutions was investigated, and the phase composition and structural parameters were explored in detail by the Rietveld method. It was found that, within the tested concentration range, Bi4–yTbyTi3O12 samples crystallize in the orthorhombic system, and the concentration evolution of the unit cell parameters was traced. It was determined that the temperature of the ferroelectric phase transition decreases with increasing y, as the concentration limit of the existence of the rhombic modification of Bi4–yTbyTi3O12 is approached.