Preparation, characterization and stability of vanadium/Y₂O₃-stabilized ZrO₂ composite membranes under different atmospheres

In this experimental work vanadium/Y₂O₃-stabilized ZrO₂ composite membrane was successfully fabricated by a two-step sintering process. The formation of a well-defined ceramic metal composite membrane was confirmed under high vacuum sintering conditions. Their surface morphology, stability and structural properties were studied as a function of temperature up to 1100°C by thermogravimetry, differential thermal analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction analysis. Significant differences were observed in the crystalline structure of the vanadium/Y₂O₃-stabilized ZrO₂ composite membranes when they were treated at high temperature in different atmospheres (vacuum, air, hydrogen, nitrogen, and helium). The first hydrogen permeation investigation of vanadium/Y₂O₃-stabilized ZrO₂ composite membrane is reported. Preliminary hydrogen permeation experiments have been confirmed that hydrogen flux was 1.08mlmin^-1cm² for a dense vanadium/Y₂O₃-stabilized ZrO₂ composite membrane (thick: 380μm) at 300°C using 100% H₂ as the feed gas. Both high temperature XRD and ex situ study showed deterioration of membranes and the formation of a small amount of vanadium nitride (VN_x) and vanadium hydride (VH_x) solid solutions under nitrogen and hydrogen gas conditions, respectively.