关键词: Ag-O系, Butler方程, 理想溶体近似, 表面张力, 表面过剩

Abstract: Surface tension, an important physical parameter of liquid metals, plays a crucial role in governing various surface phenomena. In this work, the surface tension and surface excess entropy of liquid silver were calculated using the proportion relationship between surface energy and cohesive energy. The results showed that as the temperature increased, the surface tension approximately linearly decreased, and the surface excess entropy also gradually decreased, which indicated that the liquid silver surface always maintained an ordered structure. On this basis, the liquidus line of the Ag-O system was calculated using the ideal solution approximation model, and its agreement with the experimental phase diagram validated that the system could be considered as an ideal solution. By simplifying the Butler equation, a predictive model for the surface tension of the liquid Ag-O system as a function of oxygen partial pressure and temperature was derived. The results demonstrated that at oxygen partial pressures below 10 kPa, the surface tension of the liquid Ag-O system showed a negative correlation with temperature. However, for oxygen partial pressures above 10 kPa, the surface tension initially increased and then decreased with the increasing temperature. Additionally, the surface tension of the liquid Ag-O system at 1350 K was calculated and compared with literature data, showing excellent agreement between the calculated values and experimental observations. Furthermore, the surface segregation behavior of oxygen atoms was also investigated. The study revealed that surface excess concentration was positively correlated with oxygen partial pressure and negatively correlated with temperature. It was observed that the surface segregation factor showed negative correlations with both temperature and oxygen partial pressure. At lower temperatures and oxygen pressures, oxygen atoms tend to accumulate on the surface. This research provides data support for deep exploration of the surface properties of the liquid Ag-O system and serves as a reference for optimizing predictive models of surface tension in metal-gas systems.

Key words: Ag-O system, Butler equation, ideal solution approximation, surface tension, surface excess