Soldering copper to aluminum with CU-Al2O3 composite coatings deposited by cold spraying

During the cold spraying process, the copper particles were tightly deposited on the aluminum substrate with the help of Al2O3. The results reveal that the Cu-Al2O3 composite particles can produce a coating with a thickness of 70-80 μm under particular cold spraying process, proving the feasibility of cold sprayed copper coating for soldering. SAC305 and copper blocks were used for pressureless sintering on the cold sprayed composite copper coating, and the shear strength of the solder joint obtained by reacting at 250 °C for 2 min was 34.9 MPa, and the fracture path was inside the composite coating rather than the coating-substrate interface. The wettability of SAC305 solder paste on cold sprayed copper coating were also analyzed.