| Abstract Scope |
This study investigates Sn-xZn solders (x = 1, 3, 5, 7, and 9 wt.%) were reacted with C1990 HP substrates at 240, 255, and 270 °C for reaction times ranging from 10 min to 8 h. Zn content significantly influenced intermetallic compounds (IMC) formation at the C1990 HP interface. In the low-Zn Sn-1Zn system, the interfacial reaction mainly produced (Cu,Zn)₆Sn₅, the three-phase region of L + (Cu,Ti,Zn)₆Sn₅ + Ti₂Sn₃, and (Cu,Zn,Ti)₆Sn₅. As the Zn content increased, the dominant interfacial products gradually shifted to Cu-Zn IMCs. The Sn-3Zn and Sn-5Zn systems primarily formed Cu₅Zn₈ and Ti-containing (Cu,Ti)₅Zn₈ phases, whereas the Sn-7Zn and Sn-9Zn systems mainly formed the CuZn₅ and Cu₅Zn₈. Kinetic analysis indicated that the IMC growth in the Sn-9Zn/C1990HP couple was predominantly diffusion-controlled. Ball shear testing further revealed that the Sn-1Zn/C1990 HP reaction couple reacted at 255 °C for 2 h exhibited the highest shear strength of 24.1 MPa. |