The ITDS Advantage
The ITDS (Integrated Thermodynamic Databank System) in FactSage™ contains both modules for thermodynamic calculation and modules for administration of necessary basic data. The FactSage databases contain information about the Gibbs energy of compounds and solutions as function of composition, temperature and pressure. It is easy to retrieve information about database contents before starting a calculation and it is even possible that a user adds or changes thermodynamic data and immediately sees how the changes affect the calculation results.
Solving a real-world problem requires the user to translate the problem into input for a thermodynamic calculation. Composition, temperature and pressure have to be defined as input. In the Equilib module FactSage minimizes the Gibbs energy to obtain the equilibrium phases, allowing predictions on phase stabilities. In the Phase Diagram module the Gibbs-Duhem relation is used to construct a phase diagram that allows the user to see how a change in temperature, composition or partial pressure affects the phases present in equilibrium. Thermodynamic properties can be calculated for complete chemical systems or single phases or constituents thereof. These are the chemical potential, heat capacity, enthalpy, entropy, activity and volume. These properties have various areas of application, e.g. the chemical potential of a constituent can act as driving force for diffusion while the enthalpy allows calculation of heat balances. Another popular example is cluster formation in liquid oxides (slags or glass melts): This short-range ordering is the physical origin for changes in viscosities with composition and thus can be used to calculate the viscosity.