| 摘要 |
PURPOSE:To enable the formation of a compound metal oxide, suppressing the deviation of composition from the target to a low level compared with conventional process, by adding oxalic acid to a mixed solution of respective salts of a rare-earth element, an alkaline-earth element and copper at specific ratios within a specific pH range, thereby forming a coprecipitate of the elements. CONSTITUTION:Mixed solution of chlorides, nitrates or acetates each containing a rare-earth element, an alkaline-earth element and copper at prescribed ratios is adjusted to pH 1.5-2.0 and added with oxalic acid in an amount to give a residual oxalic acid concentration of 0.05-0.1M/l. The formed coprecipitate is collected, formed into a prescribed form, calcined at 400-900 deg.C and baked in an atmosphere having partial oxygen pressure higher than that of air to obtain the objective compound oxide.
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