The Dissolution and Supersaturation of Zn in the Sn9Zn Solder Under Current Stressing

Abstract

The Sn-Zn phase diagram indicates that Sn and Zn exhibit nearly zero mutual solubility. However, this study found that Zn shows certain solubility in the Sn matrix of Sn9Zn solder under current stressing with 6000-8000 A/cm 2 . The dissolution of the Zn crystal induced by electric current was evidenced by the diminishing of the x-ray diffraction orientation of Zn(002) and the cavity formation on the Zn crystal. The Zn concentration reaches supersaturation of 4-5 wt.% at 8000 A/cm 2 . The dissolution behavior was further investigated with scanning electron microscopy and a focus ion beam of the specimen quenched with liquid nitrogen after current stressing. The morphologies of the cavities on the Zn crystals were examined and three dissolution mechanisms were identified.

Reclamation of Cobalt and Copper from Single- and Co-contaminated Wastewater via Carbonate and Hydroxide Precipitation

“…The treatability of Co and Cu via chemical precipitation in waste abatement applications is directly related to their solubilities in the solvent matrix. Their solubility profiles can be altered by one or more of the following process modifications: (1) controlling the temperature of an aqueous solution, (2) adjusting the pH and reduction potential of the solution, or (3) setting supersaturation in a fixed-volume solution [16,17].…”

“…Soluble copper hydro complexes are formed at low and high pH range in pure water and given by the reactions below depicted as Eqs. ( 14) to (17). In the presence of anionic ligands, these complexes form precipitates such as Cu(OH)2, CuCO3, etc.…”