Dealloying in Gold-Silver -- An Interface Morphology Problem

Abstract Dealloying is the selective dissolution of the less noble component under anodic conditions Dealloying can be characterized by a breakdown of the surface morphology and formation of a porous, sponge-like microstructure. Many models have been proposed to explain this phenomenon, most of which involve diffusion. The concept of bulk diffusion is considered mathematically both at high temperatures where diffusion is quite rapid and at room temperature where diffusion is much slower. Data for near room temperature diffusion in gold silver alloys are shown, demonstrating that at room temperatures, diffusion is too slow to account for dealloying. Mechanisms involving diffusion and enhanced diffusion are examined.