Pressure-Composition-Temperature PCT Properties

The relation between midplateau pressure P and temperature T is given by the well known Van t Hoff equation  

Hydrogen capacity Hc in Fig. 1.24 can be expressed in either atomic HIM ratio (H - number of H atoms, M - number of metal atoms) or weight percent (wt% ), both of which are commonly used [14], It must be noticed that calculating wt% both mass of hydrogen mH and mass of metal mM (not only mass of metal) must be considered in the denominator. 

Substituting P = lbar (or 1 atm) in (1.32) one can find a simple relationship between the equilibrium temperature (T laleau) required to give a midplateau pressure of 1 atm H2, AH and AS in the following form 

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