Enhanced tantalum hydride formation by the catalytic effect of tungsten for hydrogen dissociation

We investigated enhanced tantalum (Ta) hydride formation by using the catalytic effect of tungsten (W) to reduce the hydrogen dissociation energy. Ta turning scrap was hydrated at various temperatures by using a W crucible and conventional Al₂O₃ crucible, and the structural and chemical properties of the hydrated powders were compared. Structural investigation by X-ray diffraction and chemical analysis using an oxygen-nitrogen- hydrogen determinator showed that the Ta hydride was formed at temperatures lower than 500 °C, while the dehydride formation process occurs at temperatures higher than 600 °C in conventional Al₂O₃ crucibles. However, when the W crucible is used, the hydrogen incorporation into the Ta lattice was enhanced at both low and high temperatures. This enhancement was attributed to the reduced energy of dissociation of H₂ into mono-atomic H because of the catalytic effect of W, finally resulting in enhanced Ta hydride formation.