Thermodynamic Measurement of Phosphates by Double Knudsen Cell Mass Spectrometry

Abstract

Double Knudsen cell mass spectrometry was adapted for thermodynamic measurement of phosphates to obtain the accurate thermodynamic information. The ion currents of gaseous phosphorus and phosphorus oxides in equilibrium with a mixture of AlPO4 and Al2O3 at 1473 – 1573 K were measured by double Knudsen cell mass spectrometry. The Gibbs energy change of formation of AlPO4 was estimated by using these ion currents.