I have powder samples of Tio2 and I want to characterize it using SEM and EDS, is there any one who give me a tip for sample preparation to characterize it.
You can drop coat a dilute ethanolic solution of the powder material (well dispersed by sonication) onto thoroughly cleaned substrates.
You can drop coat a dilute ethanolic solution of the powder material (well dispersed by sonication) onto thoroughly cleaned substrates.
I have used both methods described above for Al2O3, and both work well. I wanted to mention, it can be difficult to isolate individual particles, which can sometimes make imaging difficult. I haven't used this product myself, but this company produces "tacky dot slides" that may be useful for your work.
http://www.2spi.com/catalog/new/tacky.shtml
This is very similar to the double-side sticky carbon tape method described by Dr. Konegger above, but may make it easier to isolate individual particles if that is something you wish to do. Again, I haven't used this product myself but maybe someone on researchgate has.
If you expect TiO2 to be rod or particle, sonicate in ethanol and follow the procedure given by Koneggar. If it is hollow structure (fabricated by particles), do not sonicate, make gentle shake because the structure will collapse.For SEM image, use gold coating, for electrical conduction. For EDS, do not make coating since it shows the presence of coating element also. Hope it helps
In here, we use TEM grids to deposit powder samples and observe them through SEM.
the powder is dispersed in ethanol, sonicated gently and the grid is diped in the suspension or a droplet is deposited on the grid.
Then you have no preparation more to observe the sample (in particular no gold/carbon deposiiton) since the grid is conductive.
This solution gives very nice photos on nanopwders. A bit expensive nevertheless.
Hi Dinsefa. most of the useful methods have been covered above. But I like to mention few important points which might be useful to you.
i) Sonication and putting a drop on a flat surface is a good method, but a single drop may lead to insufficient no. of powder particles for analysis. So, put a drop, let it dry, then put another drop, dry it etc. You can repeat this few times, depending on the dilution of your dispersion and finally dry it well. Also, polished surface is a much better option.than just a flat surface for this work.
ii) Using double sided carbon tape and putting your powder sample on it, is also an effective method. But sometimes, agglomerates make it difficult to image individual particles. A better method is to blow your sample in such a way that the only the lighter particles fly and stick on the sticky tape. You can master this method after few trials.
iii) Since the particles are of TiO2 and electrically insulating, you need a coating. If you want to work on both SEM and EDS, use very thin carbon (graphite) coating by arc discharge method. Carbon has only one characteristic x-ray peak in EDS spectra at the low energy side and hence the probability of overlapping with your sample peaks is remote. Gold, being a heavy element, has too many characteristic peaks and probability of overlapping is much higher and could severely limit your analysis..
addendum:
I have to say that our procedure with TEM grids is used for insulating oxide nanopowders. AND NO gold deposit needed.
If the TEM grid is a carbon-coated grid, it is the best. You can hold many particles for your analysis i.e. there is no loss of particles plus 'no charging problem'.
Please take into account that for quantitative EDS investigations the main assumption is a flat surface which you do not have. You will certainly get some signal but don't trust the quantification that much. Because of the rough surface you will have a lot a non-predictable scattering which falsify your signal in an inproper way. For EDS quantification TEM is perhaps the more reliably way...
Dear Gert, you are right. However, in EDS quantitative analysis. mostly- used software is for flat surface. But software for rough surface as well as for particle analysis are also available. The suppler of your SEM-EDS equipment can give you further information on this. BuI I know, at least, Oxford Instruments make such special software. It's all about how to get correct P/B ratio (Peak / Background).
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