High-Temperature Heat Capacity and Thermal Extension of FeTa₂O₆

The heat capacity of synthesized iron tantalate FeTa₂O₆ was measured in the temperature range of 323–1103 K by the ratio method using a thermal analyzer combining thermogravimetry and scanning calorimetry. The temperatures of phase transformations were determined. Structural changes and thermal expansion of oxide were studied in the range of 300–1173 K by high-temperature X-ray diffraction. The temperature dependences of the unit cell parameters were approximated by third order polynomials. The values of thermal expansion coefficients and anisotropy factors were calculated based on the obtained data.