Study on thermal conductivity of cold sprayed Cu coating

In order to explore the main factors influencing the thermal conductivity of the cold sprayed Cu coating, four sets of Cu coatings with different deformation and annealing conditions were prepared by high/middle pressure cold spray systems followed by the annealing procedure. Microstructure and recrystallization analysis of the coatings were characterized by SEM and EBSD. Relationship of the thermal conductivity of the coating with the porosity and particle deformation was discussed. Results show that porosity is the main factor influencing the thermal conductivity of the Cu coating. The decrease in porosity by high pressure impacting of particles can improve the conductivity of the coating, while the annealing process can further decrease the porosity by increasing the annealing temperature and meanwhile eliminate the grain boundary by grain growth and recrystallization, which makes the annealing process an effective way to improve the conductivity of the cold sprayed Cu coating.