In a reaction, if we obtain a poly-crystalline powder, we can delay the reaction time, say by decreasing the temperature etc., to obtain single crystals. Is there any such change in physical or chemical parameter, which would help me obtain single crystals where nano-particle agglomeration is happening?
I grew crystals from the solution in the melt and came to the conclusion that the most important parameter is the evaporation rate of the solvent and the ratio of the crystal density to the density of the solution. In those cases when the densities differ strongly, the regions enriched with nano-particles float or concentrate at the bottom of the container. This facilitates the formation of the crystal. The rate of evaporation increases the time for coagulation of nano-particles with the formation of a crystal.
Thank You Everybody.
Omar I have learnt this new gel based growth technique thanks to your answer which I will definitely try, Peter will try lower concentration of reactants for sure. Alexander , that is in fact a very keen observation but I still fail to see a method for me to control that phenomenon directly. Please share any insights or suggestions. Thanks again everyone.
warm regards
Shailabh
If you grow crystals in a closed reactor, the evaporation rate is determined by the magnitude of the temperature gradient of the cold and hot ends of the reactor. Reduce the value of the gradient and get a decrease in the evaporation rate and, consequently, an increase in the time for crystal formation. If your reactor is not closed, then the evaporation rate can be controlled by the diameter of the outlet.
The difference in density can be adjusted by selecting the composition of the liquid phase. more precisely, I can hardly say without knowing the nature of the crystals you grow.
- Badges
- Science topic
- Similar topics
- Engineering
- Materials Engineering
- Powders