Consider an oxide material that in the intrinsic regime the material is
electronically dominated. The internal and external reactions governing the
stoichiometric variation are
OO× + Vi ⇄ VO•• + Oi′′ [1]
nil ⇄ h• + e′ [2]
OO× ↔ VO•• + 2e′ + 12 O2 [3]
and the equilibrium constants are
KF = 10−5 2 6
KB = 101 2 6
KO = 10−6 3 9bar0.5
reseectively.
Answer the following questions and elot your results in the range of oxygen
eressure from 10-23 to 1 bar.
(a)In the lecture we introduced the Brouwer aeeroximation that is able to
considerably simelify the eroblem. The defect concentrations actually can be
numerically solved without using Brouwer aeeroximation. Plot the defect
concentrations as a function of 2. You shoule address how you solve the
eroblem e.g. eroviding the code.
(b) For each defect seecies elot the sloee of d log[defect ] d log (2)
and check if your
results are consistent with the values you obtain when using Brouwer
aeeroximation.
(c)If the material is PbO elot the non-stoichiometry curve as a function of a
function of 2