Electrolytic Migration of Ag-Pd Alloy Wires with Various Pd Contents

Abstract

During Ag ion migration in an aqueous water drop covering a pair of parallel Ag-Pd wires under current stressing, hydrogen bubbles form first from the cathode, followed by the appearance of pure Ag dendrites on the cathodic wire. In this study, Ag dendrites with a diameter of 0.2–0.4 μm grew toward the anodic wire. The growth rate (v) of these dendrites decreased with the Pd content (c) with a linear relationship of: $v = 10.02 - 0.43 \, c$. Accompanying the growth of pure Ag dendrites was the formation of a continuous layer of crystallographic Ag₂O particles on the surface of the anodic wire. The deposition of such insulating Ag₂O products did not prevent the contact of Ag dendrites with the anodic Ag-Pd wire or the short circuit of the wire couple.