In the preparation of He, CH4 is removed but the gas composition contains a variation of CO and CO2 content. The He-CO-CO2 gas leaves the reactor at 1400 K through a nichrome alloy duct. The nichrome originally containing approximately 28-mol% Cr fails and your engineering office partner determines the duct to have less than 3 mol% Cr. The alloy sometimes fails with a thick layer of Cr2O3 and other times another engineer determined that a Cr carbide formed. A third engineer determined that Cr oxide and Cr carbide were present together within the duct.
A. With the use of a calculated stability diagram, or diagrams, discuss the conditions for the formation the oxide and carbide?
B. What carbide and/or oxide forms with lowering the total pressure, CO and/or CO2 content.