Papers by Keyword: Sn-Cu

Abstract: Sn, Al and Cu not only possess electromagnetic interference shield efficiency, but also have the acceptable costs. In this study, sputtered Sn-Al thin films and Sn-Cu thin film were used to investigate the effect of the crystallization mechanism and film thickness on the electromagnetic interference (EMI) characteristics. In addition, the annealed microstructure, electrical conductivity and EMI of the Sn-xAl films and the Sn-xCu films were compared. The results show that Sn-Al film increased the electromagnetic interference (EMI) shielding after annealed. Sn-Cu films with higher Cu atomic concentration, the low frequency EMI shielding could not be improved. After annealing, the Sn-Cu thin film with lower Cu content possessed excellent EMI shielding at lower frequencies, but had an inverse tendency at higher frequencies.

Abstract: An update and the latest results on molten metal atomization using a Pressure-Gas- Atomizer will be given. This atomizer combines a swirl-pressure atomizer, to generate a liquid hollow cone film and a gas atomizer to atomize the film and/or the fragments of the film. The paper is focused on powder production, but this atomization system is also applicable for deposition purposes. Different alloys (Sn, SnCu) were atomized to study the characteristics of the Pressure- Gas-Atomizer. The powders produced were analyzed by laser diffraction and image processing. Among other parameters, the molten metal mass flow (~140 – 200 kg/h), the gas mass flow and the atomizer design were varied. The results include the effects of these variances on particle size and particle shape.

Abstract: The low-cycle fatigue behavior and the relationship between the surface features in the low-cycle fatigue testing and the fatigue life of Sn-3.5Ag and Sn-0.7Cu lead-free solders were investigated at strain rate of 0.1%/s at room temperature, 80 and 120oC. In addition, the fatigue life was estimated by using the surface deformation of the solders, and image processing. And also, it was compared with Coffin-Manson type of fatigue behavior. The fatigue life of Sn-3.5Ag solder was superior to that of Sn-0.7Cu solder at temperatures, 80 and 120oC. The fatigue life determined by surface deformation indicated a close behavior to Coffin-Manson type fatigue behavior in those solders. Therefore the low-cycle fatigue life of solders could be estimated by the surface deformation.

Abstract: The low-cycle fatigue behavior on Sn-0.7Cu lead-free solder as-cast and Sn-Pb eutectic solder as-cast were investigated at a strain rate 0.1%/s under various temperatures of 25, 80 and 120oC. In addition, the relationships between the surface feature in the low-cycle fatigue test and low-cycle fatigue life of those solders at 25oC were investigated by image processing. The low-cycle fatigue life of Sn-0.7Cu decreased when the temperature increased. And the fatigue life of Sn-0.7Cu was better than that of the Sn-Pb eutectic solder at the temperatures of 25 and 80oC. The low-cycle fatigue behavior on the solders investigated followed Coffin-Manson equation. The fatigue ductility coefficient of Sn-0.7Cu was found to be affected by the temperature. The surface deformation as fine meshes in the low-cycle fatigue test of Sn-0.7Cu did not appear until 10% of the fatigue life. Although it was over 10% of the fatigue life, the surface deformation that was caused by micro cracks and coalesces occurred with the increasing number of cycles. The relationships between the surface feature in the low-cycle fatigue test and the low-cycle fatigue life on Sn-0.7Cu and Sn-37Pb solders were discussed.