Thermal and electrical properties of Ca.sub.5Mg.sub.4-xZn.sub.x

Calcium vanadates Ca.sub.5Mg.sub.4-xZn.sub.x(VO.sub.4).sub.6 (0 [less than or equal to] x [less than or equal to] 4) have been studied for the first time using a set of high-temperature methods of analysis. The onset of melting process determined from differential scanning calorimetry decreases from 1158 to 881 °C (± 1.5 °C) with increasing of x (dopant's content). CTE temperature dependence is found to show a hysteresis. Electrical transport properties measured by impedance spectroscopy in air of different humidity are also discussed. The value of electrical conductivity does not depend on air humidity. It is found to equal to 1.5 x 10.sup.-6 S cm.sup.-1 at 720 °C for Ca.sub.5Mg.sub.4(VO.sub.4).sub.6 which is specific for garnet-related crystals.