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

The 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.