Formation of metal oxide particles by anode-discharge electrolysis of a molten LiCl-KCl-CaO system

In order to form titanium oxide particles, anode discharge was conducted with a titanium anode and a LiCl-KCl-CaO melt under 1 atm of Ar at 723 K. By applying a dc 500 V voltage, a discharge was generated between the melt and the anode whose tip was positioned above the bath surface. After anode-discharge electrolysis, black powder was obtained from the melt. From the scanning electron microscopy, X-ray diffraction, and electron probe microanalysis results, obtained powder was identified to be titanium oxide particles having diameters smaller than 150 nm. These titanium oxide particles are considered to be formed by reaction of titanium ions, which are emitted from the anode to the melt, with oxide ions in the melt. Since the sizes of these titanium oxide particles were dependent on the electrolytic conditions, the particle sizes are controllable. When a wire of iron, nickel, or copper was used as the anode, their oxide particles were obtained. (C) 2002 The Electrochemical Society.