Thermochemistry of binary alloys of lanthanum with 3d-transition metals

Abstract

The enthalpy of mixing for liquid binary alloys of lanthanum with 3d-transition metals (Sc, Ti, V, Cr, and Fe) is determined by a calorimetric method within the field of compositions rich in lanthanum. Data for the partial enthalpy of mixing in the La − 3d-metal system with infinite dilution demonstrates a complex relationship of a change in it in the series of 3d-metals connected with gradual filling of the 3d-zone due to alloy formation with lanthanum.

Thermodynamic Assessment of the La-Cr-O System

“…The calculated enthalpies of mixing are shown in Fig. 3 together with the experimentally determined value [15] that is well reproduced by the calculation. Considerable deviations of the calculated liquidus from experiments at the Cr-rich side of the system can be ascribed to the problem of two different melting temperatures for Cr cited in the literature, which are 2180 and 2130 K. The higher value was favored by Dinsdale [10] and is adopted in this study, whereas the lower melting temperature was chosen by Savitskii et al [12] and Svechnikov et al [14] A satisfying reproduction of the experimental data was obtained by considering a moderate temperature dependence of 0 L liq Cr 2þ ;La 3þ :Va and 1 L liq Cr 2þ ;La 3þ :Va .…”

“…H Cr [15] in La-Cr liquid were used to optimize the temperature-dependent regular 0 L liq Cr 2þ ;La 3þ :Va and subregular 1 L liq Cr 2þ ;La 3þ :Va interaction parameters to account for interactions between La and Cr. Furthermore the two regular interaction parameters 0 L liq Cr 3þ ;La 3þ :O 2À ¼ 0 L liq Cr 2þ ;La 3þ :O 2À and the two subregular 1 L liq Cr 3þ ;La 3þ :O 2À ¼ 1 L liq Cr 2þ ;La 3þ :O 2À were optimized.…”

“…5 calculated phase equilibria of the La-Cr-O system at 1273 K are shown as a function of oxygen partial pressure. It is obvious that no mutual solubilities of La and [15] at 1700 K included (symbol with error-bar)…”

Thermodynamic Assessment of the La-Fe-O System

“…Kepka and Skala [10] confirmed these earlier findings. Berezutskii et al [16] and Esin et al [17] determined enthalpies of mixing in La-Fe liquid from 0 to 35 at.% Fe at 1723 K and from 60 to 100 at.% Fe at 1923 K using hightemperature calorimetry.…”

“…The experimentally determined temperature and liquid composition at the eutectic in the metallic La-Fe system, [9] liquidus compositions at different temperatures, [9] and selective partial enthalpies of mixing of iron, D " H Fe [16] and lanthanum, D "…”