Internal oxidation of Ag-xIn alloys at low homologous temperature

Internal oxidation of Ag-xIn alloys (x = 10, 13, 16 at%) was studied in an air atmosphere at a relatively low homologous temperature (240 °C), where lattice diffusion is negligible. After exposure, metallic Ag nodules were present on the surfaces of all alloys, expelled to relieve stress due to internal oxidation, confirming that such coarse morphologies can be produced by short-circuit transport. Crystallographic orientation and grain boundary misorientation were found to influence nodule expulsion tendency, and the propensity for internal or external oxidation. Further analytical TEM characterization was used to study the nanoscale morphology and chemistry of nodules and internal oxide(s).