Low oxygen content fine spherical copper particles and process for producing same by fluid energy milling and high temperature processing

摘要

A powder material and a process for producing same are disclosed. The process comprises reducing the size of an electrolytically produced starting dendritic copper powder material by fluid energy milling to produce a finer powder, essentially all of which has a particle size of less than about 20 micrometers in diameter, entraining the finer powder in a carrier gas and passing it through a high temperature zone at a temperature above the melting point of the finer powder, the temperature being from about 5500° C. to about 17,000° C., to melt at least about 50% by weight of the finer powder to form essentially fine spherical particles of the melted portion, and rapidly and directly resolidifying the resulting high temperature treated material while the material is in flight, to form fine spherical particles having a particle size of less than about 20 micrometers in diameter. The particles are essentially free of elliptical shaped material and essentially free of elongated particles having rounded ends, and have an oxygen content of less than about 0.5% by weight, and a carbon content of no greater than the carbon content of the starting material.