Activity determination in the alumina–dysprosia system by Knudsen effusion mass spectrometry

• Published in: Journal of alloys and compounds Vol. 509; no. 21; pp. 6184 - 6189
• Main Authors: Motalov, V.B., Butman, M.F., Kudin, L.S., Markus, T.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 26-05-2011
• Subjects: Al 2O 3–Dy 2O 3; Alloys; Aluminum; Chemical properties; Energy of formation; Knudsen effusion; Knudsen effusion mass spectrometry; Lamp envelopes; Mass spectrometry; Oxides; Powders–gas phase reaction; Vaporization; Vaporizing; Al 2O 3–Dy 2O 3; Chemical properties; Knudsen effusion mass spectrometry; Powders–gas phase reaction; Lamp envelopes; Vaporization
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2011.01.166

► Vaporization of Al-Dy-O mixtures has been investigated by KEMS. ► The problem of attainment of thermodynamic equilibrium has been described. ► The activities of Al
2O
3 and Dy
2O
3 have been measured at
T = 2130 K. ► The Gibbs energies and enthalpies of compound formation have been determined.
The vaporization of Al–Dy–O mixtures has been investigated by the Knudsen effusion mass spectrometry technique. The saturated vapor has been found to consist of the atoms Al, O and the molecules AlO, Al
2O, DyO. At the initial stage the vaporization of Dy
2O
3 and Al
2O
3–Dy
2O
3 mixtures was found to be incongruent and accompanied by some loss of oxygen. An attainment of congruently vaporizing composition and equilibrium state takes quite a long time. The activities of binary oxides have been measured at
T
=
2130
K. The Gibbs energies and enthalpies have been derived for formation of the compounds Dy
4Al
2O
9, DyAlO
3 and Dy
3Al
5O
12 from sesquioxides.