Preparation of a fine powder composed of oxide–metal composite by an arc-plasma method

Fine oxide–metal composite powders have been prepared under an H2–Ar gas environment using an arc-plasma irradiation technique. Initial Cu particles with grain sizes between 10 and 30 μm were mixed with TiO2 powder of submicron size at different weight ratios to form targets by sintering. Mixtures with varying Cu/TiO2 weight ratios were prepared, but mostly a mixture with the weight ratio at 95:5 was used. The targets were exposed to arc-plasma irradiation to form a fine composite powder. Particles prepared are Cu-fine core particles each coated with a thin film of TiO2. The thickness of the oxide film ranges from a few nanometers to some tens of nanometers, and is independent of the ambient gas composition and irradiation. The size distribution of prepared composite particles is broad, and most of them range from 20 to 100 nm. H2 gas in the chamber plays a significant role in forming the composite powder.