The preparation of Zr-deuteride and phase stability studies of the Zr-D system

Deuteride phases in the zirconium-deuterium system in the temperature range 25-286\(\celsius\) have been studied in-situ by high resolution neutron diffraction. The study primarily focused on observations of \(\delta \rightarrow \gamma\) transformation at 180\(\celsius\), and the peritectoid reaction \(\alpha + \delta \leftrightarrow \gamma\) at 255\(\celsius\) in commercial grade Zr powder that was deuterated to a deuterium/Zr ratio of one to one. A detailed description of the zirconium deuteride preparation route by high temperature gas loading is also described. The lattice parameters of \(\alpha\)-Zr, \(\delta\)-ZrD\(_x\) and \(\epsilon\)-ZrD\(_x\) were determined by whole pattern crystal structure analysis, using Rietveld and Pawley refinements, and are in good agreement with values reported in the literature. The controversial \(\gamma\)-hydride phase was observed both in-situ and ex-situ in deuterated Zr powder after a heat treatment at 286\(\celsius\) and slow cooling.