Thermophysical measurements on dysprosium and gadolinium titanates

Dysprosium and gadolinium titanates were prepared by the solid state route and by the wet chemical route. The compounds were characterized using inductively coupled plasma mass spectrometry (ICPMS) and X-ray diffraction (XRD) techniques. Their thermal expansion coefficients were measured using high temperature X-ray diffraction technique. The quasi-isotropic mean linear thermal expansion coefficient (alpha) over bar (m) of Dy2TiO5 and Gd2TiO5 at room temperature are 6.55 x 10(-6) and 6.56 x 10(-6) K-1, respectively, and in the temperature range 298-1573 K are 1.006 x 10(-5) and 1.023 x 10(-5) K-1, respectively. Heat capacity measurements were carried out in the temperature range 320-820 K using differential scanning calorimetry. From the polynomial fit the C-p.298 of Dy2TiO5 and Gd2TiO5 have been computed to be 178.26 and 168.61 J K-1 mol(-1), respectively. (C) 2004 Elsevier B.V. All rights reserved.