Oxygen Solubility and Activity in Liquid Antimony.

The solubility limit of oxygen in liquid antimony has been measured by a novel isopiestic technique in the temperature range from 995 to 1175 K. The results can be expressed by the equation log c equals -5500/T plus 3. 754( plus or minus 0. 04) with c in at. % O and T in K. The oxygen potential over Sb plus O alloys in equilibrium with Sb//2O//3 has been measured by a solid state galvanic cell using a fully stabilized CaO multiplied by (times) ZrO//2 electrolyte. The cell was designed to contain the Sb plus Sb//2O//3 mixture in a closed volume, so that the vaporization of the oxide can be minimized and true equilibrium attained. The standard enthalpy and entropy of the solution of oxygen in Sb are compared with values for other metal-oxygen systems and with the standard enthalpies of formation of corresponding oxides. The resulting correlations permit the estimation of the standard free energy of solution of oxygen in pure metals for which experimental information is lacking.