Axial thermal expansion of ZrO 2 and HfO 2 in the range room temperature to 1400°C

The axial thermal expansion of monoclinic and tetragonal ZrO 2 and of monoclinic HfO 2 was studied over the temperature range from room temperature to 1400 °C. The linear thermal expansion coefficients were calculated. Thermal expansion along (x 10 6 per °C) a = 10.31 monoclinic ZrO 2 , 11.60 tetragonal ZrO 2 , 9.34 monoclinic HfO 2 ; b = 1.35 monoclinic ZrO 2 , – tetragonal ZrO 2 , 2.98 monoclinic HfO 2 ; c = 14.68 monoclinic ZrO 2 , 16.08 tetragonal ZrO 2 , 13.10 monoclinic HfO 2 . Some aspects of the present study, such as anisotropy of thermal expansion and a pretransformation vibrational anomaly, are discussed briefly.