Abstract
A cold spraying process has been developed for dense and clean and tightly bonded coatings in contract with other established thermal spraying processes. The cold sprayed copper is particularly well suited for metallic coatings, such as electric conductor and heat-sink. However, the microstructure of copper coatings formed by the cold spraying have not always been clarified everything. Two kinds of free-standing copper specimens, which were formed by the cold spray process and an atmospheric plasma spray process, were machined from the thick coatings and were used for measuring the density, microstructure, oxygen distribution and pore size distribution. As a result, it was confirmed that the cold sprayed copper showed remarkable high density and low oxygen content in comparison with the atmospheric plasma sprayed copper. Also, these experimental results showed that the pores below the size of a few μm in diameter could not be observed in case of the cold sprayed copper though the pore size distribution of the atmospheric plasma sprayed copper was extensive.
