Dealloying of a Ag-Cu-Ti Alloy in Liquid Sodium at 350 °C

Dealloying of Ag-35.2Cu-5.4Ti in liquid Na at 350 degrees C was studied with emphasis on its microstructural evolution, kinetics, and degradation in bonding capability. Ag in the alloy was continuously dissolved into liquid Na, leaving behind porous a Cu-Ti-rich structure. Bonding strength of dealloyed region was determined by combining experimental and analytical approaches. Dealloying kinetics at the initial stage obeys the linear rate law since its rate-limiting step is dissolution of Ag. As dealloying proceeds, diffusion of dissolved Ag in the liquid Na becomes the rate-limiting step triggering negative deviations from the ideal linearity as can be derived from the Noyes-Whitney equation.