| abstract |
A process for producing ultrafine mixed-crystal oxide particles which comprises gas-phase production of metal oxides through high-temperature oxidation of metal halides with an oxidizing gas, characterized in that the metal halides are a mixed gas comprising at least two compounds which are selected from the group consisting of the chlorides, bromides, and iodides of titanium, silicon, and aluminum and differ at least in metal element (mixed metal halide gas), and that the mixed metal halide gas and the oxidizing gas are preheated to 500°C or higher and then reacted to produce ultrafine oxide particles containing primary particles which have a BET specific surface area of 10 to 200 m2/g and are in a mixed-crystal state; ultrafine oxide particles obtained by the process; and a use of the oxides. |