Thermodynamic measurement of Dy + Fe binary system by double Knudsen cell mass spectrometry

• Thermodynamic information of Dy + Fe system was measured with mass spectrometry.
• The activities of Dy in Dy–Fe alloys were measured at (1273 to 1573) K.
• The standard Gibbs energies of formation of intermetallic compounds were estimated.

The activities of Dy in Dy–Fe alloys with Dy concentrations ranging from (7.0 to 89) at% were determined at (1273 to 1573) K by measuring the ion current of the vapor of Dy in equilibrium with Dy–Fe melts, Dy2Fe17 + γFe, etc. The standard Gibbs energy of formation of Dy2Fe17, Dy6Fe23, DyFe3, and DyFe2 were calculated from the activities of Dy obtained from these measurements.