Temperature Influence on the Morphology and Roughness of Silver Deposit Formed by Cementation

Abstract

AbstractThe morphology and surface roughness of silver deposits formed by cementation in 0.5M H2SO4 solution containing 0.5M CuSO4 was investigated at various temperatures. The influence of O2 on the morphology of deposited Ag on the Cu surface was studied in solutions containing 20 or 100 mg/dm3 initial Ag+. Surface‐height‐distribution diagrams were calculated from scanning‐electron‐microscopic (SEM) images. For the lower Ag+ concentration, the formation of granular deposits occurred in the presence of O2. In contrast, under anaerobic conditions, rather flat deposits with tiny Ag crystals were observed. For the higher Ag+ concentration, the presence of O2 did not significantly affect the morphology of the Ag deposit, but increasing temperature resulted in more‐compact and denser dendrites. Differences in the Ag‐deposit morphology and surface roughness were attributed to a different mechanism in the absence of O2. Under anaerobic conditions, a competitive reaction between Ag+ and Cu+ occurs in bulk solution, which consumes additional Ag+ ions. The SEM images and, especially, distribution diagrams of the surface height provided useful information on the formation and expansion of anodic sites on the Cu surface at various temperatures.