In-situ investigation of Hf6Ta2O17 anisotropic thermal expansion and topotactic, peritectic transformation
Source abstract
Abstract
Abstract The anisotropic coefficients of thermal expansion and the peritectic transformation of orthorhombic-Hf6Ta2O17 to tetragonal-HfO2 plus liquid at 2250 °C have been studied by in-situ X-ray powder diffraction from room temperature to complete melting (∼2450 °C) in air, using a quadrupole lamp furnace (QLF) and a conical nozzle levitator (CNL) equipped with a CO2 laser. The topotactic, peritectic transformation has been fully described by extracting the orientation relationship, lattice variant deformation and a motif (grouping) of cations that relates the two structures at the transformation temperature. The calculation of these two important parameters as well as identification of the motif is facilitated by a knowledge of the anisotropic coefficients of thermal expansion as a function of temperature. Symmetry decomposition has been performed to show that the orthorhombic-Hf6Ta2O17 and tetragonal-HfO2 structures are simply related by polyhedral rotations and loss of 1 mol of oxygen.
Source: openaire · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Microwave Dielectric Ceramics Synthesis · Nuclear materials and radiation effects · X-ray Diffraction in Crystallography
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
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