| 摘要 |
PURPOSE: Copper powder and process for producing copper powder are provided, which obtain copper powder capable of obtaining an integrated sintered product free from gaps even in the case sintering temperature is low at the time of forming an external electrode of a laminated ceramic capacitor by sintering to copper powder. CONSTITUTION: The copper powder has an average particle diameter in the range of from not less than 0.1 mum to less than 1.5 mum, that has a narrow particle size distribution width whose value A defined by Equation (1) below in terms of X25, X50 and X75 defined below is not greater than 1.2, and that forms a pseudo-fused sintered product when held at a temperature of 800 deg.C under an atmosphere of inert gas at one atmosphere pressure: A=(X75-X25)/X50 (1), where X25, X50 and X75 are values of particle diameter X corresponding to Q% =25%, 50% and 75% on a cumulative particle-size curve plotted in an orthogonal coordinate system whose abcissa represents particle diameter X (mum) and ordinate represents Q% (ratio of particles present of a diameter not greater than the corresponding value of X; expressed in units of vol % of particles). The copper powder is produced by conducting wet reduction of cuprous oxide into metallic copper powder in the presence of ammonia or an ammonium salt. When used to form the terminal electrodes of multi-layer capacitor, it enables the electrodes to form into solid sintered bodies with few pores by sintering at a low temperature.
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