SGTE is a consortium of European and North-American research
organisations working together to develop high-quality thermodynamic
databases for a wide variety of inorganic and metallurgical systems. SGTE
has been at the forefront of the broader international effort to unify
thermodynamic data and assessment methods by promoting use of standard
reference data for the elements and binary systems, and generic models to
represent the variation in thermodynamic properties with temperature and
composition. NPL is a founding member of SGTE.
SGTE data can be obtained via members and their agents for
use on personal computers with commercially available software, to enable
users to undertake calculations of complex chemical and phase equilibria
efficiently and reliably.
Members of SGTE have played a principal role in promoting the concept
of ‘computational thermochemistry’ as a time- and cost-saving basis for the
control and modelling of various types of materials process. In addition,
such calculations provide crucial process-related information regarding the
nature, amounts and distribution of environmentally hazardous substances
produced during the different processing stages.
SGTE have developed a number of thermodynamic database for a wide range of technologically
important materials. Such databases contain critically assessed data, a set of
model parameters which describe as accurately as possible
experimental thermodynamic and phase diagram data for binary, ternary systems and higher order systems.
The models are based on physical
principles which make it possible to extrapolate the critically assessed data
to commercially important multi-component systems.
Extrapolation from several assessed lower order systems require that these systems are internally consistent
and this take time and effort to achieve. At present, a number of commercially interesting as well
as scientifically challenging materials have been collected into databases which are available and
listed below. The SGTE Databases are under continuous development.
SGTE databases include
The SGTE Pure Substance Database containing assessed
thermochemical data for about 4000 condensed
compounds or gaseous species.
The Unary database containing assessed thermochemical data
for all stable and many metastable modifications from 298.15 K up to the
gaseous state for many elements. These descriptions of the thermodynamic
properties of the elements are used as a basis for all SGTE databases.
Solution database which contains data
for the liquid phase and various crystalline phases of the pure elements in
addition to over 400 binary, ternary and quaternary alloy systems. The data
have been derived by a process of critically assessment taking all the relevant
experimental data, eg enthalpies of mixing, partial pressures, solubilities, thermal
arrests etc and then using them to derive a small number of coefficients
representing how the thermodynamic properties of the system change with
temperature and composition.
Thermal Barrier Coating database
was developed in the Max-Planck-Institute Institute for Metal Research in Stuttgart. It
covers the system ZrO2-Gd2O3-Y2O3-Al2O3 and is suitable for calculations between 300 K
and 3000 K, but in particular above 1100 K. Most of the phases stable in the system are solid solutions
described using the compound energy formalism. The liquid phase was described using the
two-sublattice partially ionic liquid model. Yyttria stabilised zirconia (YSZ) itself has various industrial applications.
For example, the phase with the fluorite structure is used as a solid electrolyte. The tetragonal phase with 6-8 wt. % Y2O3
is used as a thermal barrier coating (TBC) on a metal substrate. Co-doping of the traditional YSZ with Gd enhances the insulating
efficiency of thermal barrier system. A thin layer of alpha-Al2O3 (thermally grown oxide, TGO) forms between metallic bond coat and the TBC in the
process of thermal cycling. Therefore, phase relations in the ZrO2-Gd2O3-Y2O3-Al2O3 system are important to
understand the interactions between TBC and the TGO, stability issues of TBC materials and interactions within multilayer TBC.
The SGTE database for molten salt systems was based
partly on a compilation of data for Alkali metal halides from Sangster and Pelton but modified
considerably to present self-consistent modelling of data across complete
The SLAG database consists of data for the liquid slag and condensed oxides
for the Al2O3-CaO-FeO-Fe2O3-MgO-SiO2 system.
Recently, data for Na, Cr, Ni, P and have been added and thus allow calculation of
sulphide capacities of slags. The liquid slag is described with the cell model
proposed by Kapoor-Frohberg and modified by Gaye. Composition variations in the
solid oxides have not been taken into account.
The III-V semiconductor database contains the 15
possible binary systems between the group III elements Al, Ga and In and the group V elements P, As and Sb.
The noble metal alloy database contains evaluated
thermodynamic parameters for alloys of Ag, Au, Ir,
Os, Pd, Pt, Rh, Ru alloyed amongst themselves and also in alloys with the
metals Al, As, Bi, C, Co, Cr, Cu, Fe, Ge, In, Mg,
Ni, Pb, Sb, Si, Sn, Ta, Te, Ti, Tl, Zn, Zr. The database
provides a good starting basis for development of data for higher-order noble
metal systems. At the same time, the assessed data it contains for the binary
and ternary sub-systems of Au-Pd-Pt-Sn allow
calculations relevant to dental alloy development.
The SGTE Nuclear Database has been
generated as part of a much bigger database effort to cover many thermochemical
aspects related to the field of nuclear reactors. This database is specially
made for the investigation of in-vessel chemical reactions. The elements
included in the database are O, U, Zr, Fe, Cr, Ni,
Ar, H. Also included are systems formed among the 6 oxides UO2, ZrO2, FeO, Fe2O3, Cr2O3, NiO. The database
covers the entire composition range from pure metal to oxide regions and
contains critically evaluated thermodynamic parameters for all relevant
multicomponent condensed or gaseous substances and solution phases.
SGTE has also been involved in publication of data through the Landolt Börnstein series. Two sets of volumes
have been produced so far dealing with:
Subvolumes A Pure Substances
Subvolumes B Binary systems
future set of subvolumes is under way covering specific ternary systems
relevant to technologically important classes of materials.
Substances - Subvolume A: Heat Capacities, Enthalpies, Entropies and Gibbs
Energies, Phase Transition Data
A. Elements and Compounds from AgBr to Ba3N2
B. Compounds from BeBr‹g> to ZrCl2‹g>
C. Compounds from CoCl3 to Ge3N4
D. Compounds from HgH‹g> to ZnTe‹g>
Systems - Subvolume B: Phase Diagrams, Phase Transition Data, Integral and
Partial Quantities of Alloys
A. Elements and Binary Systems from Ag-Al to Au-Tl
B. Binary Systems from B-C to Cr-Zr
C. Binary Systems from Cs-K to Mg-Zr
D. Binary Systems from Mn-Mo to Y-Zr