THERMODYNAMIC CALCULATION AND 3D MODELING T-x-y AND P (Se2) -T-x DIAGRAMS IN THE SYSTEM Cu-Pb-Se ON LIQUIDUS PbSe

Abstract

From the condition that the chemical potentials of the components of the AB compound
are equal in the equilibrium liquid and solid phases, taking as pure liquid components as the standard
state, equations are obtained for calculating and modeling of partial excess thermodynamic functions,
of the pressure-temperature-composition diagram and liquidus surfaces of the binary compound in
the ternary system A–B–C. The equations obtained are tested on the Cu–Pb–Se system in the liquidus
region of the PbSe compound. It is shown that the vapor phase mainly consists of two atomic molecules
of selenium Se2. For the liquidus regions PbSe(p-type)-Se and PbSe(n-type)-Pb, the following
dependences are obtained, respectively:
lg Se p 2 (Pa) = [–1281 + 5624(1000/T) – 9190(1000/T)2 + 6648(1000/T)3 – 1797(1000/T)4] – 10.35 xCu
2 ;
lg Se p 2 (Pa) = [2026 – 8778(1000/T) + 14247(1000/T)2 – 10259(1000/T)3 + 2759(1000/T)4] – 8.36 xCu
2 .
For the thermodynamics calculation and modeling of surface crystallization PbSein the ternary system
Cu -Pb-Se is obtained dependence:
T = [ + ( - x ) Gexs (xl )] / [ . - . ln x ( - Cu
.
PbSe Se Se 110693 1 0 35D 25 695 8 31 1 xSe )]
Where DGexs l
PbSe
, = –76057 + 335550,738хSe – 2,41759E6хSe
2 + 7,33249E6хSe
3 – 9,7868E6 хSe
4 + 4,69725E6хSe
5.
3D visualization of the obtained analytical dependencies is carried out with the help of a computer
program OriginLab2017.