I was doing TEM sessions with my samples which consist of Ni-Mo-O-S and then I found this particle shape, but it definitely doesn't belong to my sample. This is a perfect wheel shaped particle and the mid is purely crystalline as it shows diffraction rings.
At least you should analyze your "wheel shape" by TEM-EDX to be sure that the sample composition contains no impurity.Maybe this sample exposured electron beam was formed during TEM analysis..or you may have an impurity on your sample, you should also think the impurity on your TEM grid..
I know it is an impurity, and I could never find this particle again. At that time EDX wasnt available and later I couldnt find this shape again. Just wonder if anyone came across with similar shapes of particles...
yeah I agree with serdar that most probably the object may some iprity on grid. But Muxina if this is the case u may never come across it again and better u should continue establishing its identity
The "wheel" bears a striking resemblance to some diatoms. Is it possible that there was a source of diatomacious earth contamination in the lab. These could have come even from the polish used to clean up metal components of the TEM.
I agree with Barry, my thought on first seeing is that the image resembles that of a diatom.
Hi Muxina here i found a same shaped of a Diatoms. http://www.bcvideo.com/new-evidence-supressed.html
Thank you for everyone for your suggestions.. Very useful comments. Diatoms look very similar to my impurity image. Just wonder how it ended up in TEM grid.....
hi, it appears to be mug or could be an inclusion type. I have also found similar once in my Al-Sc alloy ( it was looking like a fruit ) but not same shape as beautiful as in your case. I could not to find it elsewhere or afterwards.
Look at these diatom bodies. Allegedly there are about 10000 varieties of diatoms.
It appears to me there may be more radial "rods" at various angles to the viewer. Also, the wheel "rim" could be a cross-section of something more like a sphere. I would not rule out a virus or related form.
thank you all for your comments. Apparently they are not diatoms. I am getting them again in my other samples. Now trying to find out how they are formed....
It is hard to judge by diffraction, polycrystalline particles lying on top of each other...
Can't suggest. Seeing for the first time. It looks non-homogeneous. Why not find its composition?
Muxina, why did you write "Apparently they are not diatoms"? what did it make you believe so, which evidence? if also in another sample, I would first assume you have the same / similar source of contamination by such diatom earth.
Initially i was confident it is diatoms as we had silica impurities .however it is composition a bit different than most of diatoms ....anyway,it could be still impurity as i still can't find exact composition...and remains mystery ...
I have never seen this "this particle shape" before.
But I can tell you this for sure; it doesn't look like a "particle" at all - you might as well consider calling 'this' a "structure"...
A bicycle like wheel. Check the literature "http://onlinelibrary.wiley.com/doi/10.1002/ange.201302362/abstract" . It may give you some idea how they are formed.
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