Thermodynamic Assessment of the Silver–Oxygen System

Abstract

An assessment of the silver–oxygen system has been made, and a consistent set of thermodynamic parameters has been optimized. The calculated thermodynamic properties and phase relations are in good agreement with the experimental data. Ag2O is the only phase that is commonly found within the system. In air, it decomposes to silver and oxygen gas at 420 K. There is a eutectic between silver and Ag2O at a temperature of 804 K, an oxygen partial pressure (PO2) of 526 bar (5.26 × 107 Pa), and an oxygen mole fraction in the liquid phase of 0.25. Uncertainties remain on the Ag2O liquidus for PO2 > 108 Pa. An ionic two‐sublattice model has been used to describe the liquid phase. This work is part of a study of interactions between compounds from the bismuth‐strontium‐calcium‐copper‐oxygen system and silver.

Effects of silver addition on microstructure and electrical properties of barium titanate ceramics

“…It suggests that no reaction took place between BaTiO 3 and silver during calcinations and sintering. Thermodynamic studies have suggested that silver is more stable than Ag 2 O at temperatures of >189.8 • C in air [15]. Therefore, any Ag 2 O that is present decomposes to metallic silver during the calcination heating-up stage.…”

Enhanced dielectric properties of bismuth titanate/silver composites

“…Despite the fact that the sintering process was conducted in air, no silver oxide is found in BiT/Ag composites. Since silver is more stable than silver oxide above 189.8 • C in air [18] and the formation of Ag 2 O is a very slow process at low temperature [19], the amount of Ag 2 O formed during the cooling stage may be too little to be detected via the XRD technique. The X-ray diffraction results indicate that metallic Ag phase is compatible with BiT matrix.…”

Electro-catalytically Active, High Surface Area Cathodes for Low Temperature SOFCs

“…As shown earlier, linear trends in ASR with time are observed, and the degradation rate of silver-ESB composites at 650 °C was reduced from 4.10 × 10 -4 Ωcm 2 /h to 1.91 × 10 -5 Ωcm 2 /h-a 95% drop with the reduced ESB particle size. mobility in silver 40,41 and, as shown earlier, the application of a bias across the cell leads to an electro-migration effect where the silver phase is dragged along in the direction of oxygen flux.…”