| 摘要 |
<p>A process for producing a powder mixture of a noble-metal powder and an oxide powder is provided which comprises mixing a powder of the ammonium chloride salt of a noble metal with an oxide powder and subsequently roasting this mixed powder to eliminate the ammonium chloride and thereby obtain the powder mixture of a noble-metal powder and an oxide powder. Also provided is a powder mixture comprising a noble-metal powder and an oxide powder, the powder mixture having a chlorine content lower than 1,000 ppm and a nitrogen content lower than 1,000 ppm, 90% or more of the noble-metal powder having a particle diameter of 20 µm or smaller, and 90% or more of the oxide powder having a diameter of 12 µm or smaller. Step duplication in noble-metal powder production is avoided, and steps are omitted so that inclusion of the chlorine contained in aqua regia or of nitrogen, which participates in hydrazine reduction reaction, is minimized. As a result, the step of drying at a high temperature is omitted to prevent particle growth or aggregation, and pulverization and classification steps are omitted to attain a marked reduction in production cost.</p> |
