Vapor pressures in the {Al(l) + Al2O3(s)} system: Reconsidering Al2O3(s) condensation

The vaporization behavior of the Al–O system has been studied on numerous occasions but significant uncertainties remain. The origin of this uncertainty must be understood before Al–O vaporization behavior can be accurately determined. The condensation of Al2O3 and clogging of the effusion orifice is a difficult problem for the Knudsen effusion technique that influences the measured vaporization behavior but has only received limited attention. This study reconsiders this behavior in detail. A new theory for Al2O3 condensation is proposed together with procedures that will improve the measured thermodynamic properties of Al–O vaporization.