My substrate is Magnesium, it was electroless "Ni-P" coated.
I went to another test facility for EDX test to verify the contents of the coating. A Pt coating was put on it prior to FESEM and EDX at the test centre. As a result, the EDX pattern showed Pt peaks when the findings were released. But only Nickel and Phosphorous were deposited on the substrate in my work.
SO should I just ignore the Pt content in the EDX results or not ?
Dear Chandra Sekhar Rauta ,
to my opinion, it depends on what you want to see...
a) First of all you have Pt detected*) by your system and, as I deduced from description, the your substrate was in contact with Pt, but has been removed in some way. But I expect, that there might be still Pt residuals there, but, I think, in a quite low concentration.
b) If the presence of the Pt lines do not bother your further peak evaluation you can just ignore**) them. But be careful, there are a lot of Pt lines in the low energy region ( ~1,6 to ~2,8keV).
c) you should share the spectrum...( & kV value)
*) Which peaks of Pt have been used identify Pt?; there should be at least the Pt L-alpha line(s) at about 9,4keV and/or the Pt M-alpha line at about 2,05keV.; depending on the applied electron beam voltage.
**) only 'ignore', but not delete them in the spectrum
Best regards
G.M.
It's a bit difficult to understand your question. Was your specimen Pt-coated as a part of specimen preparation for FESEM? Anyway, you can "ignore" Pt in your discussion only after you have mentioned that you believe Pt peak originated because of Pt coat.
Thank you for your responses Gerhard Martens Vladimir Dusevich , here is my detailed query. Hope you will understand it correctly now.
My substrate is Magnesium, it was electroless "Ni-P" coated.
I went to another test facility for EDX test to verify the contents of the coating. A Pt coating was put on it prior to FESEM and EDX at the test centre. As a result, the EDX pattern showed Pt peaks when the findings were released. But only Nickel and Phosphorous were deposited on the substrate in my work.
SO should I just ignore the Pt content in the EDX results or not ?
Dear Chandra Sekhar Rauta ,
thanks for feed back.
So, your magnesium substrate was sucessively coated by 'Ni-P' and afterwards for the case of FESEM by a bit of Pt (e.g. to prevent charging ?).
So you will have definitely Pt in your EDX spectra. But so far you can ignore the Pt 'content' in the result list, as Vladimir Dusevich already mentioned above.
However, as I wrote above, please take care on the evaluation of the peaks in the 1,6 to 2,8keV region; because of the Pt peaks therein, you may have superposition with your coating peaks.
For the case of 'P' as part of the coating, you will have the P K-alpha(s) at about 2,013keV and P K-beta at at 2,14keV. The Pt M-alpha line is at 2,05keV and there is are also Pt lines at 2,07 and 2,13 keV. I have doubts, that your FESEM detector system can distinguish the P lines from the Pt lines. I do not know, how efficient the ZAF correction is working here.
So the Pt lines will affect the result of the P content.
For the case of Ni, I do not see any peak superpositon with Pt lines.
Best regards
G.M.
Thank you Gerhard Martens . Yes , I'm having the same issue you mentioned. The peaks for P and Pt are close together, and the wt% for Pt is 6 vs to P's 3 and Ni's remaining. How will I portray the EDX data if I omit the Pt wt%? How accurate and reliable will the new composition be?
Dear Chandra Sekhar Rauta ,
I fear that there is no satisfactory anwer to your issue.
When mutually skipping the Pt content you may use the 3% of P and the 91% of Ni as starting points and scale their sum to 100%.
But I think, both of the starting wt% numbers for P and Ni are wrong because the geometry of your sample system is not matched to the prerequistes for the application of the ZAF correction; that is to my opinion a homogenous distribution of all kinds of atoms in the sample.
In contrast to that, you have a Pt layer on top, which causes an energy dependent attenuation of the fluorescence peaks from the Ni-P layer.
One can deduce that the P content is underestimated in that case, because of the high attenuation coefficient of Pt ( Z=78) in the 2keV regime. For Ni the situation might be a bit better if their L-lines are not used, but only the Ni K-lines.
Nevertheless there is a large question mark for the 3% of P and the 91% of Ni.
One might do MC simulations for your sample system and fit the EDX spectrum, but with known mass coverage of the Pt layer. But that is a full-time job, which cannot be done while crossing a doorstep...
Best regards
G.M.
Most FESEM labs can coat a specimen with carbon instead of Pt or other metal. You may want to repeat your analysis with another, carbon coated specimen.
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