Click on Download EpH Slide Show (pdf presentation - 30 pages) for detailed information on the EpH Module.

The EpH module enables you to generate isothermal Eh vs. pH (Pourbaix) diagrams for one-, two or three-metal systems using data retrieved from the compound databases that also include infinitely dilute aqueous data. Note: EpH only accesses compound databases - the aqueous phase is treated as an ideal solution.

Figs. 2 to 4 show the input and resulting Eh-pH diagram for the Cu-water system.

Figs. 5 and 6 show how to generate a ‘two-metal’ Eh-pH diagram for the Cu-As-water system. Since the stabilities of the Cu and As mixed compounds (Cu₃(AsO₄)₂(s) and Cu₃As(s)) depend upon the relative amounts of Cu and As, it is also necessary to define the range of the metal mole fraction R, As / (As + Cu).

The calculated diagrams can be stored as figure (*.fig) files, edited by the Figure module, and exported as *.bmp, *.emf and *.wmf files.

EpH also enables you list the coordinates all the invariant points as well as perform detailed equilibrium calculations at any point on the diagram. You can also calculate diagrams under constant partial gas pressures.

 

Fig. 1 - EpH Module Fig. 2 - EpH Module - The Cu-water Eh-pH diagram: the Elements frame. Fig. 3 - EpH - Specifying the Cu water Eh-pH diagram: the Calculate frame. Fig. 4 - EpH - Cu-H2O Eh-pH diagram: Graphical Output. Fig. 5 - EpH - The Cu-As-water Eh-pH diagram: the Metal Mole Fraction frame. Fig. 6 - EpH - The Cu-As-water Eh-pH diagram: graphical output.