Electrical Resistivity of Two-Phase Lead-Free Solders

Author: Frances Holcomb

Field of Study: Physics; Mathematical Sciences

Program Affiliation: Cotts Lab

Faculty Mentors: Eric Cotts

Easel: 17

Timeslot: Midday

Abstract: Solders are crucial components of microelectronics and circuits. In many cases, solders with low melting points are useful to avoid damaging the circuit during application. Previously, lead-tin was the leading low-temperature solder, but the negative environmental and health impacts of lead warrant the use of a substitute. Tin-bismuth has arisen as a promising candidate because it has a low eutectic temperature. It is therefore important to understand the electrical resistivity of the alloy for use in electrical circuits. In the present work, several compositions of tin-bismuth are analyzed and their resistivity is plotted against composition. A mathematical model is applied to the system and shows good agreement with the data without fitting parameters. The model's excellent fit signifies its ability to explain the effects of composition on the electrical resistivity of tin-bismuth and its possible usefulness for modeling other two-phase systems.