Abstract: | The solubility of Ag2O was measured for the Na2O–B2O3 and Na2O–B2O3–Al2O3 system with the rotating crucible method and static method, respectively, under air atmosphere at temperatures ranging from 1273 to 1423 K. The contamination of melts from crucibles could be avoided by the rotating crucible method, with which it became possible to measure the solubility of Ag2O for the Na2O–B2O3 system above the melting point of Ag for the first time. It was found that the addition of Na2O decreases the solubility of Ag2O while the addition of Al2O3 had little effect on the solubility. The effect of Na2O and Al2O3 on the solubility of Ag2O is expressed by interaction coefficients and is analyzed in terms of the basicity of melts. The solubility of Ag2O in Na2O–B2O3–Al2O3 melts increased with increased temperature. This phenomena was explained by a small enthalpy change in oxidation of silver. |