I have prepared pallets for ionic conductivity measurement. The size of the particles ranging from 0.5-2 microns. Is there any significant change in ionic conductivity and density of pallet will be observed if I will prepare the same samples with size less than 1 micron using planetary ball milling?
Dear Dheeraj Kumar Maurya , I assume you want to measure the ionic conductivity of a solution which is surrounding and flooding your pellets.
It shouldn´t show any difference in ionic conductivity, given the ions are much smaller than the holes between nanoparticles (microparticles), so they should be able to move freely in both types of pellets.
About the density, it is curious, because the original particles (0.5-2 microns) could be more tightly packed than the new ones (< 1 micron). The reason is that in the first case small particles could fit on the holes left by the bigger ones, while in the second case, assuming a more regular distribution of sizes (low polydispersity). Say that holes left by 1 um particles are too small to host 0.7 or 0.8 um particles.
If particle distribution or polydispersity is high in this second case, the tiniest particles could be placed in the holes left by the bigger ones and the pellet would be more compact and dense.
Hope it helps.
Dear all, it is a matter of the interparticles interstitial volume that remains after sintering. My Regards
Dear Dheeraj Kumar Maurya
When similar ionic conductivity values are achieved for both pallets formulated from coarse and finer powders, the higher sintering temperature is obtained for the coarser one as a result of its lower grain surface energy and reactivity.
Now, higher sintering temperature will provide dense pallets but enhance the grain growth and increase the diffusion kinetics and the segregation at grain boundaries and so the grain boundary resistance contributes less and so only the grain bulk resistance is responsible for total pallets conductivity while for finer grain pallets (less than 1 micron), sintering temperature provide less dense pallets and lower the grain growth and diffusion kinetics and the segregation at grain boundaries and so the grain boundary resistance contributes higher at this lower sintering temperatures and only the grains boundary resistance is responsible for total pallets conductivity. So you can see that the final density of pallets is depends mainly on sintering temperature which is effectively promotes lattice, surface and grain boundary diffusion for densification and coarsening process and as you know that the final pallets density is highly related to the densification process.
Best regards
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