Consolidation Model of CBPC Formation

To start with, for simplicity, let us assume that all particles are of equal size in the oxide powder. If the radius of individual particles is 2r and if we take rr particles and pack them in a cube of each side 2m, then the total volume of the cube will be 8r n. The acmal volume occupied by the particles is, and hence the void space between the particles 

SEM microphotograph of a fully reacted berlinite bonded alumina ceramic. 

The net amount of reaction product that would be formed is governed by the solubility of the particular product. As we have noted before, the reaction products that are responsible for bonding are formed between pH 2 and 8. As we have noted before, dissolved fraction of the oxide at a given pH is given by 

In the case of corundum, for example, first hydrargillite (A103/2 f H2O) is formed at pH 5, which then converts into berlinite bonding phase. Thus, the total fraction of the oxide dissolved between pH 5 and 8 is given by 

Since J dx = In b, we can integrate right-hand side of Eq. 11.29 and obtain, 

---