2.15 A Simple General Procedure for Constructing a Brouwer's Diagram

1. First one needs to determine how many defects are relevant. This can be, to a large extent, determined by crystal structure, solute concentration and electrical conductivity or diffusion rates. For example, one can neglect Frenkel defects i.e. interstitial for closed packed structures where Schottky defects can be dominant i.e. K_F << K_S.
   
   
2. Write independent defect reactions for each defect and K values e.g. oxidation and reduction are not independent, related through intrinsic electronic reaction.

• Intrinsic defect formation mechanism

• Oxidation or reduction (not both)

3. N-1 equations are obtained for N defect concentrations and another electronically apparition.
   
   
4. Define regions of pO₂.
   
   
5. Observe which defect concentration decreases or increases with the change of pO₂.