Manufacturing and characterization of Magnéli phase conductive fibres

Abstract

This paper reports a simple and inexpensive method for preparing fine scale (Ø 260 μm) and high-density Magnéli phase (Ti_nO_2n−1) conductive ceramic fibres. The structure of the fibres was characterized by X-ray diffraction and scanning electron microscopy and their phase and microstructure was related to frequency dependent impedance measurements. The process employed is capable of producing dense (>96%) Ti-suboxide fibres, and by using a reduction temperature of 1200 °C and 1300 °C it is possible to produce Magnéli phase fibres. The electrical conductivity of the reduced fibres can be tuned in a range of five orders of magnitude (10⁻¹–10⁴ S m⁻¹) and the increase in conductivity was 10¹³ relative to stoichiometric TiO₂. Such novel conductive fibres have the potential to be used as a sensing element, electrode, catalyst support and in energy storage applications.