SYNTHESIS, STRUCTURE, LUMINESCENT AND MECHANICAL PROPERTIES OF YNbхTa1–хO4 SOLID SOLUTIONS

A series of mixed yttrium tantalo-niobates (YNbхTa1–хO4, x = 0-1) is obtained by the sol-gel synthesis. It is shown that the temperature of this synthesis of YNbхTa1–хO4 and its duration are much lower than those in the solid-phase synthesis. The properties of both synthesized powders and ceramic solid solutions (SSs) YNbхTa1–хO4, x = 0-1, prepared based on them, are investigated. It is found that under UV excitation at any Nb:Ta ratio in YNbхTa1–хO4 SSs the luminescent signal is enhanced as compared to that in individual YNbO4 and YTaO4 compounds, which is caused by energy transfer between the Nb4+–O– and Ta4+–O– luminescence centers. Morphological features of the microstructure of ceramic YNbхTa1–хO4 SSs are studied. Mechanical characteristics of ceramic YNbхTa1–хO4 SSs, such as Young's modulus and the stress intensity factor for mode 1 KIC, which is a criterion of the material crack resistance, are estimated.