Copper-based composites for thermal conductive components were prepared via cold spray process,and their microstructures,size distribution of Cr particles extracted from the coating,and adhesion morphology of feedstock powders on Cu substrate were evaluated.Cu-based composites were fabricated using Cu-Cr mixed powders with their mixture ratio of 20,35,50 and 65 mass% Cr onto OFC (Oxygen-Free Copper)substrate with N2 carrier gas.The Cr-content ratio in the coating is approximately 50-60 % of feedstock mixture ratio due to the low formability of the hard particles.Most of Cr particles extracted from the coating are flattened,and the size distribution with less than approximately 30 μm decreases compared with the starting feedstock,which is attributed to their higher critical velocity.Amorphous-structured oxygen-rich layer exists at Cr particle/Cu interface,which contributes to the deposition of the Cr particles.Since the individual Cr particle attaches to Cu mechanically,it can be inferred that the Cr particles easily fall off by gas flow.However,the Cr particles trapped by the deformable Cu particles remain in the coatings.Therefore,it is expected that using Cu-Cr composite singleparticles might be effective means for the improvement of adhesion and deposition efficiency.Key Words:Cold spray,Cu-based composite,Particle size distribution,Cr/Cu interface,Oxygen-rich layer,Adhesion morphology.

抄録全体を表示