Molten Salt Synthesis of Intermetallic Compound TiNi Nanopowder Passivated by TiOx Shell Prepared from NiTiO3 for Catalytic Hydrogenation

Abstract

Titanium-nickel alloy is an attractive material due to its unique properties of shape memory effect, superior elasticity, and biocompatibility. Generally, Ti-Ni alloy powders are prepared from pure elemental powders of Ti and Ni as starting materials, but it is an energy-intensive process to obtain pure titanium. In this study, intermetallic compound TiNi powder passivated by TiOx shell was prepared by directly reducing a commercial NiTiO3 using CaH2 reducing agent in a molten LiCl at 650 °C. Analyses by X-ray diffraction, scanning electron microscopy/transmission electron microscopy with energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy revealed that the powder had a core-shell structure, with the core of TiNi and the shell of TiOx-rich composition with scarce metallic Ni nicely catalyzing hydrogenation reactions with good recyclability and stability.