Soldering aluminium to copper with the use of interlayers deposited by cold spraying

The article presents the application of interlayers deposited by Low Pressure Cold Spraying (LPCS) in the soldering process. The problems concerning soft soldering of aluminium and copper were indicated and a solution with the use of metallic and composite interlayers was proposed. Wettability and spreadability tests with selected solders were performed to evaluate a solderability of various aluminium and copper LPCS coatings. Light and scanning microscopes were used to analyze solder dissimilar Al–Cu joints with previously deposited LPCS interlayer. What is more mechanical properties of the joints, e.g. microhardness and shear strength, were examined. Strength of the soldered Al–Cu joints with the LCPS interlayer highly depend on shape of powder used in spraying process. The joints with the interlayer sprayed with dendritic copper powder have low strength of about 20 MPa. However, the strength of soldered joints with the LPCS interlayer of spherical copper powder is significantly higher and amounts to 36.7 MPa.