Dear Khasan Ziyoyiddin Ugli Nasriddinov ,

you should not rely on only one peak.

By nature two phases may exhibit peaks, which overlap within the resolution of the XRD pattern at a specific angular position.

In your case the Fe (bcc lattice, noiseless red curve) has a peak (110) at about 44,2° and one (200) at about 65,2°.

The Fe5C2 (blue curve) has got a peak also at about 44,2° but none in the 65° regime.

Your sample (noisy red curve) gas got peaks having positions similar to Fe5C2, but the peak heights do not match. This may be due to preferred orientation artifacts. However at around 65° there is no peak visible sticking out of the noise.

Thus to my opinion you have got no iron in your sample.

But you should repeate your sample scan on a much increased time scale to increase the signal to noise ratio.

Look at even higher angle for the 211 of alpha-Fe, that is due to multiplicity higher than 200.

Note, moreover, that the unit cell of Fe is small ageainst the Hägg carbide. Hence a small volume/mass fraction of alpha-Fe should already be quite visible. This means that even if you do have alpha-Fe in your sample, it is not a lot.

I am reconsidering very old data on Fe-C system, with Xrd and Ms that I have collected in the previous century.

I find really useful the two PhD thesis of Paasi Paalanen (2020) and also the less recent work by Esna Du Plessis.

You will find there a complete framework ( Paalanen) and thorough experimental work ( Du Plessis)

There are still some iron carbides structures that should be clearly identified and this happens on 2021...

Best regards and good luck!

FM

simple cheack—- Run XRF on the sample, and see if iron exhibits an excess in the mole wt calculations of your iron carbide, too much iron means metallic iron OR other iron species

In addition to what Fabio Miani mentioned:

Esna Du Plessis is RG member:

https://www.researchgate.net/profile/Esna-Du-Plessis-2

You may have a look at her RG page.

Please not the triclinic structure by Du Plessis. This was pointless! See Article Crystal structure determination of Hägg carbide, χ-Fe5C2 by ...

Thank you Gerhard Martens for your kind observation, I believe Esna du Plessis thesis work should be studied and directly cited more.

The original Url is

https://ujcontent.uj.ac.za/vital/access/manager/Repository/uj:1863?site_name=GlobalView

http://hdl.handle.net/10210/421

This month of May 2021, I am discussing in the last two weeks of my course of metallurgy in a small workshop approach work her findings applied to the identification of Iron Carbides in my previous century data.

Here are some data from her thesis work ( hoping that my students would work property and possibly improve them) along with an older NBS data on Fe3C.

If any of you has time here, one could join (from remote!) the discussion on the old ( but good?) original data obtained by ball milling ( or mechanochemical synthesis)

graphic preview of data is at

http://www.gotrawama.eu/metallurgia21/CMC10log10.tiff

the same of the attached tiff file here