Copper flake powder, method for producing copper flake powder, and conductive paste using copper flake powder

摘要

The present invention is mainly for providing a flake copper powder for a conductive paste with particle properties which are defined by that the particle thickness is thinner being possible for use to form an electrode or a circuit, and a production process thereof. To achieve the object of producing the following particles, each powder particles shape is plastically processed into a flake-shape, wherein the flake copper powder has a cumulative particle diameter D₅₀ of 10 mum or smaller measured with laser diffraction scattering particle size distribution method. The D₁₀, D₅₀ and D₉₀ measured with the laser diffraction scattering particle size distribution method are illustrative and the SD/D₅₀ value measured by the standard deviation of particle distribution with the laser diffraction scattering particle size distribution, is 0.55 or larger and/or a D₉₀/D₁₀ of 4.5 or smaller. The flake copper powder is compressed with a high energy ball mill whose media beads having fine particle diameter which plastically deforms the copper particles into flake-shaped particles, so that stable flake copper powder is produced.