COPPER PARTICLES AND METHOD FOR MANUFACTURING SAME
Copper particles are provided mainly containing a copper element. In the copper particles, a ratio (S1/B) of a first crystallite size S1 to a particle size B is 0.23 or less, where the first crystallite size is obtained using Scherrer equation from a full width at half maximum of a peak derived from ( 111 ) plane of copper in X-ray diffraction measurement, and the particle size is calculated from a BET specific surface area. In the copper particles, a ratio (S1/S2) of the first crystallite size S1 to a second crystallite size S2 is 1.35 or less, where the second crystallite size is obtained using Scherrer equation from a full width at half maximum of a peak derived from ( 220 ) plane of copper in X-ray diffraction measurement. A method for manufacturing the copper particles is also provided.
1 . Copper particles mainly comprising a copper element,
wherein a ratio (S1/B) of a first crystallite size S1 to a particle size B is 0.23 or less, the first crystallite size being obtained using Scherrer equation from a full width at half maximum of a peak derived from ( 111 ) plane of copper in X-ray diffraction measurement, and the particle size being calculated from a BET specific surface area, and
a ratio (S1/S2) of the first crystallite size S1 to a second crystallite size S2 is 1.35 or less, the second crystallite size being obtained using Scherrer equation from a full width at half maximum of a peak derived from ( 220 ) plane of copper in X-ray diffraction measurement.
2 . The copper particles according to claim 1 , wherein the particle size is from 100 nm to 500 nm.
3 . The copper particles according to claim 1 or 2 , wherein a ratio (S1/S3) of the first crystallite size S1 to a third crystallite size S3 is 1.25 or less, the third crystallite size being obtained using Scherrer equation from a full width at half maximum of a peak derived from ( 311 ) plane of copper in X-ray diffraction measurement.
4 . The copper particles according to claim 1 , wherein the copper particles contain a carbon element, and a content of the carbon element is 1000 ppm or less.
5 . The copper particles according to claim 1 , wherein the copper particles contain a phosphorus element, and a content of the phosphorus element is 300 ppm or more.
6 . A method for manufacturing copper particles, comprising:
a first reduction step of reducing copper ions, thereby producing cuprous oxide; and
a second reduction step of reducing the cuprous oxide, thereby producing copper particles,
wherein polyphosphoric acid with two or more phosphoric acid units or a salt of the polyphosphoric acid is allowed to be present in a reaction system during or before the second reduction step.
7 . The manufacturing method according to claim 6 , wherein the first reduction step and the second reduction step are performed in a same reaction system.