The results of the investigation of the high temperature decomposition reactions in vacuum under equilibrium conditions of ytterbium silicides in the whole composition range are reported. By means of the Knudsen Effusion–Mass Spectrometry (KE–MS) and the Knudsen Effusion–Weight Loss (KE–WL) techniques, the Yb(g) vapour pressures in equilibrium over the various high temperature and low temperature biphasic regions were measured in the temperature range 781–1395 K and the reaction enthalpies for the respective decompositions were derived. From this set of experimental data we derived for the first time the heats of formation of all the six known Si–Yb intermediate phases. The following values fH 298 are recommended: Si3Yb5=48.33.6, Si4Yb5=53.24.6, SiYb=51.15.1, Si4Yb3=48.03.1, Si5Yb3=41.32.6, Si1.74Yb=37.40.9, all in kJ/mol atoms.
Thermochemistry of ytterbium silicides / Brutti, S.; Ciccioli, Andrea; Balducci, Giovanni; Gigli, Guido; Pietro, Manfrinetti; Andrea, Palenzona. - In: INTERMETALLICS. - ISSN 0966-9795. - 11:11-12 SPEC. ISS(2003), pp. 1153-1159. (Intervento presentato al convegno International Meeting on Thermodynamics of Alloys- tenutosi a ROME, ITALY nel SEP 08-13, 2002) [10.1016/s0966-9795(03)00152-3].
Thermochemistry of ytterbium silicides
S. Brutti;CICCIOLI, Andrea;BALDUCCI, Giovanni;GIGLI, Guido;
2003
Abstract
The results of the investigation of the high temperature decomposition reactions in vacuum under equilibrium conditions of ytterbium silicides in the whole composition range are reported. By means of the Knudsen Effusion–Mass Spectrometry (KE–MS) and the Knudsen Effusion–Weight Loss (KE–WL) techniques, the Yb(g) vapour pressures in equilibrium over the various high temperature and low temperature biphasic regions were measured in the temperature range 781–1395 K and the reaction enthalpies for the respective decompositions were derived. From this set of experimental data we derived for the first time the heats of formation of all the six known Si–Yb intermediate phases. The following values fH 298 are recommended: Si3Yb5=48.33.6, Si4Yb5=53.24.6, SiYb=51.15.1, Si4Yb3=48.03.1, Si5Yb3=41.32.6, Si1.74Yb=37.40.9, all in kJ/mol atoms.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.