Nihon Superior’s Keith Sweatman to Discuss Applications for Tin-Zinc Eutectics at IPC APEX EXPO 2011

The presentation will be held during the session titled “Lead-Free Reliability,” which will take place Thursday, April 14, 2011 from 10:15-11:45 a.m.

With a melting point of 199°C, about 20°C lower than the liquidus temperature of SAC305, the tin-zinc eutectic appears to be an attractive candidate as a lead-free solder. With, at July 2010 market prices, a raw material cost less than half that of SAC305, the tin-zinc eutectic also has the attraction of substantial cost savings. Additionally, in contrast with silver, zinc is a relatively abundant element of low toxicity with a comparatively low impact on the environment.

In this paper, the authors report studies that indicate that with the use of a microalloying addition of manganese, joint integrity can be maintained on nickel, brass and silver substrates, r. Tin-zinc alloy solder joints were exposed to high temperatures (150°C) and humid heat (85°C/85 percent RH) for up to 1000 hours, the mechanical properties measured and the microstructure monitored. Joints also were exposed to salt water and electric current under heat and humidity. These studies indicate that there is potential for a wider use of alloys based around the tin-zinc eutectic in electrical and electronic assembly. .