| 摘要 |
PROBLEM TO BE SOLVED: To 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. SOLUTION: In this copper powder in which the average perticle size lies in the range of 0.1 to <1.5μm, and the width of the particle size distribution is narrow in such a manner that the A value conforming to the following formula (1) among the values of X25, X50 and X75 defined in the following shows 1.2 or less, the same is made into a pseudo-fused sintered product when held to 800 deg.C in the atmosphere of inert gas under one atmospheric pressure: A value = (X75-X25)/X50...(1), wherein X25, X50 and X75 denote the respective particle sizes (μm) corresponding to Q%=25%, 50% and 75% in a cumulative particle size curve with the particle size X (μm) as the axis of abscissas, and Q% (the ratio in which the particles of the same particle size or less are present, and the unit denotes the volume % of the particles) as the axis of ordinates. The copper powder can be obtained, in the case of wet reduction from copper suboxide into metallic copper powder, by performing the same in the presence of ammonia or an ammonium group.
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