SGTE Unary database
The development and use of databanks for the calculation of complex multi-component phase equilibria has made it necessary to adopt standards for the critical assessment of data. The basis for the whole process is the definition of reference data for the thermodynamic properties of the elements (and other key components) in various phases in which they may occur or dissolve.
Through the years SGTE has determined and compiled such data in the form of Gibbs energies of the elements in various crystaline states and in the liquid state. This compilation has been used as the basis for very many assessments of binary and higher order alloy systems, initially by members of SGTE, meanwhile by many other scientists from the field. These subsystems can, thanks to the use of the same data for the component elements, be combined into higher order systems and thus make it possible to investigate real world alloys.
It is SGTEs general policy to make the data for the elements freely available to the scientific community. Please make appropriate use of them. In case you want to set up a new database for an alloy system you can extract the necessary phase component data from SGUNBase while you assemble the basic solution phases such as Liquid, FCC_A1, BCC_A2 etc.
There is however one other case of use of the SGUNBase: When ChemSage *.DAT files have been converted into FactSage compatible databases it may so happen that not all elementary components of the chemical system contained in the *.DAT file are treated as Pure Substances, i.e. pure stoichiometric solids, liquids or gases. For example in the Cr-Ni system there are only components of the three solutions Liquid, FCC_A1 and BCC_A2.
Thus the required entries for pure solid Cr and Ni which FactSage searches for when chemical inputs are defined, e.g. in the Reactants Screen of Equilib, will not be found and an error message will occur. This problem, and thus the error message, is avoided if one selects not only the converted ChemSage database files but also the SGUNBase for search of the elements and phases.
A final note: If you come across missing data or if you encounter data problems in the SGUNBase, please do not hesitate to contact us.