Effects of thermal cycling on shear strength of soldered joints of laminar ceramic resistor
(College of Materials Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China)
Abstract: The shear strength of two joints with different compositions (Sn63Pb37 and SnAg3.0Cu0.5) was compared under thermal cycling conditions, and the effects of thermal cycling times on the two different joints were studied. Results indicate that the shear force of the joints soldered with lead-free solder is higher than that of the joints soldered with Sn-Pb solder. After 120 times thermal cycling, the shear force of both the two kinds of joints declines obviously. The fractures are located at the two interfaces which is between the resistor’s side pad and the ceramic, the other is between the resistor’s bottom pad and the solder. Analysis result on the fractures by means of SEM indicates that the micrographs of fractures change obviously and the grains grow coarser after thermal cycling.
Key words: reliability； laminar ceramic resistor； shear strength