Hello,
I measured the XRD pattern of a high alloy steel sample with a size of 24x1mm with the Bruker D2 Phaser device and noticed that the measurement result looked like an n-shape as in the image.
When I took measurements with with other ferrous/non-ferrous samples of different thicknesses in order to check whether the problem was in the device or in the sample thickness, the measurement was carried out without any problems.
What could be the reason for this?
You can see the images containing my measurement parameters below.
Can Zümrüt
The shape of the diffraction pattern with a hump can be associated with the fact that steel is a solid solution with an amorphous structure, where there are islands of an ordered crystalline structure with rare peaks.
Dear Can Zümrüt ,
I wonder the area of your sample being 24x1mm².
Did you restrict the incoming beam in such a way, that it hits only that small stripe or does the primary beam additionally hit part of the sample support, being at different height level?
Do your 'other' samples have the same stripe dimensions?
Perform a blank scan without that sample, but using the same sample support at the same height position as in your scan presented above...
With respect to the amorphous issue: in general the increasing and the falling part of amorphous humps exhibit concave like curvature, but not a convex one.
Best regards
G.M.
No, steel is not a solid solution with amorphous structure!
Your very high background results from using a copper anode source with a material that is mostly iron. This results in very high background due to copper characteristic radiation being very effective in stimulating fluorescent radiation from iron.
Fe fluorescence could be part of the reason,
but, I think, in the Bruker D2 Phaser the fluorescence is removed via the energy dispersive detection mode?
Can Zümrüt , do you have used that option*) ?
A it is mentioned above by Can Zümrüt , other ferrous samples do not show that behavior...
*) for example: https://www.bruker.com/en/products-and-solutions/diffractometers-and-x-ray-microscopes/x-ray-diffractometers/d2-phaser/xe-t.html
I see some rather non-standard measurement conditions. 30kV is OK, but 10 mA seems low to me. The reason for the unusual background shape is probably a combination of what has already been mentioned here: low tube power, small sample width and also fluorescence. It would also be a good idea to check whether there is a shift in focus at different angles across the sample.
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