Effect of Silicon, Vanadium, and Tungsten Oxide Additives on the Electrical Properties of Composites Based on CaWO4

A study is made of the effect the nature of a heterogeneous highly dispersed additive has on the electrical properties of composites based on an oxygen-ion conductor (calcium tungstate). Heterogeneous doping of CaWO4 is found to sharply increase ionic conductivity, regardless of the physicochemical properties of the dispersed additive. New data on the electrical properties and morphology of CaWO4–SiO2 composites are obtained. It is shown that a composite with 6 mol % nanosized silica has ionic conductivity an order of magnitude stronger than that of CaWO4. The composite effect of increasing ionic conductivity is discussed using the model for the formation of a coherent dispersed system in which a highly conductive film that forms at an interphase boundary acts as a bonding matrix.