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Experimental Determination of CaO–CrO–Cr 2 O 3 –MgO–SiO 2 and Thermodynamic Modeling of the CrO–Cr 2 O 3 –MgO–SiO 2 System
Author(s) -
Arnout Sander,
Guo Muxing,
Jung InHo,
Blanpain Bart,
Wollants Patrick
Publication year - 2009
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2009.03115.x
Subject(s) - liquidus , phase diagram , chromium , calphad , analytical chemistry (journal) , thermodynamics , phase (matter) , thermodynamic equilibrium , solid solution , partial pressure , chemistry , materials science , mineralogy , oxygen , metallurgy , physics , organic chemistry , chromatography
This article focuses on the CaO–CrO x –MgO–SiO 2 system at low CaO contents, providing quantitative phase relation data, and improving the thermodynamic description. The observed liquidus data are compared with literature data and state‐of‐the‐art thermodynamic calculations (FactSage 5.5). The experimental phase diagram measurements are performed under various conditions: (1) liquidus of CaO–CrO x –MgO–SiO 2 at a basicity CaO/SiO 2 =0.5 (by weight), at 1500°C and at a partial oxygen pressure p O 2 =10 −11.04 atm, (2) liquidus of CaO–CrO x –MgO–SiO 2 at 1600°C and p O 2 =10 −9.36 atm with constant molar ratio Mg/Cr of 1/2 and varying basicity, (3) phase equilibria of the CrO–Cr 2 O 3 –MgO–SiO 2 system at 1600°C and p O 2 ranging from air to equilibrium with metallic chromium. In the experiments, equilibrium samples of crystalline phases and melts are analyzed by electron probe microanalysis using wavelength dispersive spectroscopy to determine both solid and liquid compositions. Some discrepancies from previous literature data and calculations are found. In order to improve the thermodynamic calculations, a new thermodynamic model of the CrO–Cr 2 O 3 –MgO–SiO 2 system is also developed using the Modified Quasichemical Model for the liquid and the compound energy formalism for the solid solution phases. The newly optimized model parameters can describe the present experimental data and literature data more accurately.