Gallium (Ga) is one of the intermetallic elements that has been used in cancer treatment for a long time. However, Ga compounds are increasingly being used to make high-speed semiconductors and photoelectric devices. The current work investigated physiological and pathological changes in zebra fish ( Danio rerio) exposed to various Ga3+ levels (0.55, 1.5, and 3.85 mg/L) over a 14-day test period. Decreases in oxygen consumption were significant ( p < 0.05) for groups exposed to 3.85 Ga3+ mg/L; this was associated with the fusion of zebra fish gills lamellae. Serum biochemical changes (including aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase) were consistent with observations of damage to organelles within the hepatocytes at higher Ga3+ exposure levels (1.5 and 3.85 mg/L) in zebra fish. We propose <0.55 Ga3+ mg/L as a biologically safe concentration that can be used to establish water quality criteria for this teleost model.

Typically, Sn cannot be finished on Ni and Ag surfaces via the immersion process. In this work, through galvanic reaction, immersion Sn finish was processed on an immersion Ag finish coexisting with a Ni surface. Herein, the detailed mechanism of the reduction of Sn2+ ions on the immersion Ag surface through galvanic reaction is reported. Through transmission electron microscopy and X-ray diffraction analysis, the uncommon Ag4Sn phase, instead of the common Ag3Sn phase, was confirmed to form during the Sn immersion of the Ag immersion layer. The Ag4Sn phase was found to form between the Ag grains in the immersion Sn layer. The mixed Ag/Ag4Sn structure in the immersion Sn layer can be explained by the galvanic reaction. The preferred formation of the Ag4Sn during the Sn immersion of the Ag immersion layer is discussed from the viewpoint of thermodynamics. The changes in the Gibbs free energy of the formation of the Ag3Sn and Ag4Sn phases were calculated as −3.67 and −8.89 kJ/mol, respectively. This confirms that the Ag4Sn phase is the favorable phase formed in the immersion Sn over the immersion Ag layer.