Hi all,
I have an alumina sample in powdered form, and I'm trying to characterize it (the only information I have is that it's alumina). The XRD pattern of this sample is attached.
Below are some of the things that I've noticed but have trouble understanding:
- Is the slope between 0 - 10 degrees normal? If not, how should I solve this issue? For my other crystalline samples I've never observed something like this.
- The peak intensity is less than 200, which seems quite low to me. The background noise also seems quite signficant, but there are still some identifiable peaks between 30 - 70 degrees. I'm therefore having doubt about whether this a good quality XRD pattern that I can use, or is this a bad quality/invalid result?
- Also, is there a possibility for this to be amorphous alumina?
Any help is greatly appreciated, thanks in advance.
Dear Siqi Wang ,
just a few comments:
a) the negative slope of the XRD pattern in the low 2theta range might, to my opinion, be an artifact due to misalingment of the sample height position (you should increase/play around with the height/surface position of the sample).
b) the sample surface seems to be very rough, which will cause 'height' issues and thus will contribute to the uncertainty of theta (giving rise to peak broadening); your powder particles may be too large....
c) with respect to the quite 'low' signal; the amount of material may be too low; what is your estimated thickness?
d) what is the opinion of the XRD operator?
He should know the experimental aspects...
e) for Alumina peak positions please have a look for example at Fig. 3.1.d at:
Article Mullite glass ceramics production from coal ash and alumina ...
f) Do you deal with alimina NPs? Please see for example Fig. 1 of:
Article Immobilization of Kluyveromyces lactis β galactosidase on co...
Here the peak widths are due to small crystallite size...
Best regards
G.M.
Dear Siqi Wang
The attached diffraction pattern does not closely resemble that of corundum (alpha alumina). But nothing can be seriously evaluated from the picture. The identification of synthetic Al oxides is not entirely easy either. It is several tens of crystal structures, many of them are defective, transient. It will be necessary to measure a higher quality pattern and then compare it with the database. The beginning of the pattern is influenced by the scattering of radiation in the air. An anti-scatter (knife) slit may helps. It is not even necessary to solve this, the weak intensity and high noise are worse. It is possible that this is a mixture of an amorphous substance with a small amount of crystallites. I can possibly try to evaluate it, but I would need a raw or data (ie xy) file.
yes I can help you but I need a file in xrdml or raw format.
1- is a bad acquisition with a very low counts. You have to redo the acquisition with the right parameters.
2-between 0 and 30 c is normal. if you want to correct you have to change FDS to ADS
I think your XRD machine step size is too high. Its better to redo the measurement with small step size.
Try to heat the sample to high temperatures, approximately ( 1000 -1200)C . I have worked on Alpha Aluminum and I can help you.
To get a sustainable solution to your problem, please refer to the preprint article given at link DOI: 10.13140/RG.2.2.27720.65287/3 or at link https://www.researchgate.net/publication/352830671.
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