Dear All,
I have synthesized a material using combustion method. The synthesized material calcined at 1350C for 6h. Then I record XRD pattern, reveals coexistence of two crystallographic phases with small impurity phase. After this, I perform SEM measurement for microstructural study. In the micrograph(s), I observed two different morphologies in different regions. What will be the reasons?
To answer your question it is essential to know TWO things -
1. How many chemical species are there in your system (C); e.g. if you have Fe and Al then applying Gibb's Phase rule 0=C-P+1; maximum 3 phases can be obtained assuming constant pressure (atmospheric) under equilibrium condition; where P is number of phases.
2. Is your sample equilibrated? if not then the above rule is no longer valid; e.g. in Fe-Al system one can mix Al5Fe2, Al13Fe4, Al and Fe at room temperature and can can say 4-phase coexists!! which would be wrong; because sample has not been equilibrated in terms of chemical potential of individual component in each phase.
Hope this would help to find your answer.
The sample which I have synthesized is a ceramic oxide containing Nd, Ba, Mn, Ti and O, calcined at atmospheric pressure in open oxygen atmosphere.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science