Evaluation of Wettability between Pure Aluminum and Lead, Lead-Tin by means of Interfacial Impedance Technique

Abstract

In order to estimate the wettability between aluminum sheet and solder, the interfacial impedance response at the interface between solid aluminum and liquid lead or lead-tin alloy was measured. The sessile drop method was also carried out to compare the wettabilities at various temperatures. It was found that the impedance for the Al/Pb interface, the compensated impedance of external measuring circuit, consists of the parallel connection of capacitance and resistance. The capacitance value is about 0.02 Fm⁻² in the non-wetting interface of Al and Pb–Sn melts at the temperatures below 823 K. However, the capacitance changes to 4 Fm⁻² above 873 K, where good adhesion of the Pb–Sn alloy is improved and this is in good agreement with the result of the sessile drop method and the interface observation by scanning electron microscopy.