Question

Liquid iron, contained in an Al2O3 crucible under a gaseous atmosphere of po, = 3x10-12 atm at 1600°C, contains its equilibrium contents of dissolved oxygen and aluminum. To what value must Po, be raised in order that solid her- cynite (FeO.A1,03) appears in equilibrium with the melt and with solid Al,03? What is the activity of Al (with respect to the 1 wt% in Fe standard state) in this state? How many degrees of freedom does this equilibrium have at 1600°C? Given 102(g) = 0 (1 wt% in Fe) AG° =-111,070 – 5.877 J Ali) = Al(1 wt% in Fe)AG° = -43,100 – 32.267 J FeO· Al2O3(-) = Fe() +01 wt% in Fe) + Al2O3(s) AG° = 146,230 – 54.35T J