Synthesis and reactivity of single-phase Be17Ti2 intermetallic compounds

• Preliminary synthesis of single-phase Be17Ti2 was succeeded.
• Reactivity difference between beryllium and beryllides may be caused by a lattice strain.
• Oxidation of Be17Ti2 at high temperatures results in the formation of TiO2.
• Simulation results reveal that a stable site for hydrogen at the center of tetrahedron exists.

To investigate feasibility for application of Be17Ti2 as a neutron multiplier as well as a refractory material, single-phase Be17Ti2 intermetallic compounds were synthesized using an annealing heat treatment of the starting powder and a plasma sintering method. Scanning electron microscopic observations and X-ray diffraction measurements reveal that the single-phase Be17Ti2 compounds were successfully synthesized. We examined the reactivity of Be17Ti2 with 1% H2O and discovered that a larger stoichiometric amount of Ti resulted in the formation of TiO2 on the surface at high temperatures. This oxidation may also contribute to an increase in both weight gain and generation of H2. This suggests that the formation of the Ti-depleted Be17Ti2−x layer as a result of oxidation facilitates an increased reactivity with H2O. To evaluate the safety aspects of Be17Ti2, we also investigated the hydrogen positions and solution energies based on the first principle. The calculations reveal that there are 10 theoretical sites, where 9 of these sites have hydrogen solution energies with a positive value (endothermic) and 1 site located at the center of a tetrahedron comprising two Be and two Ti atoms gives a negative value (exothermic).