Quantitative phase analysis from XRD data is still delicate matter. On paper it's doable, but from a practical point of view you might find difficulties in actually doing it. The answer is therefore case-dependent. For instance SIROQUANT like any other software based on the Rietveld method, assumes that you have identified and you know the structure of all crystalline phases present in the specimen. As an alternative you can use the PONKCS method (you can google for it) that can work in a more general case. Given just a diffraction pattern showing an unknown amorphous hump, the quantification is hardly achievable

Yes, it is possible.

SIROQUANT can measure the amorphous

content by “spiking” the sample with a known weight of

an internal standard, e.g. corundum, which is not already

present in the sample. The sample is then subjected to a

normal Rietveld quantification with SIROQUANT. If

there is any non-diffracting material in the sample, the

internal standard weight percentage found by the

program, (X), will be greater than the weighted amount,

(Y). The amorphous content in the spiked sample is

given by the following equation:

Wa = 1−(Y/X)

where, Wa is the weight fraction of the amorphous

content in the spiked sample,

Y is the weighed amount

of spike, and

X is the amount found by the Rietveld

program

I ment also percentage of amorphous content through XRD

Thank you for the detailed answer.

Dear Anagi M Balachandra,

Yes, under certain circumstances, XRD will tell you approximation on the non-crystalline phase. You need to run Rietveld refinement for this purpose.

Thanks!

Quantitative phase analysis from XRD data is still delicate matter. On paper it's doable, but from a practical point of view you might find difficulties in actually doing it. The answer is therefore case-dependent. For instance SIROQUANT like any other software based on the Rietveld method, assumes that you have identified and you know the structure of all crystalline phases present in the specimen. As an alternative you can use the PONKCS method (you can google for it) that can work in a more general case. Given just a diffraction pattern showing an unknown amorphous hump, the quantification is hardly achievable

QPA of amorphous content is possible and, in an ideal case, can provide similar accuracy as that achieved with crystalline phases.

Discussion of methodology can be found in:

Description and Survey of Methodologies for the Determination of Amorphous Content Via X-Ray Powder Diffraction

December 2011 Zeitschrift für Kristallographie 226(12):944-955

DOI: 10.1524/zkri.2011.1437

Ian C. Madsen, Nicola Scarlett and Arnt Kern

I'm fairly sure that the full text is available via Researchgate. If not, send me a message and I'll send a PDF of the paper.

I forgot to mention some of the problems in determining amorphous content especially that of microabsorption when using the internal standard method.

This is discussed in detail in:

Effect of microabsorption on the determination of amorphous content via powder X-ray diffraction

March 2018 Powder Diffraction 33(01):26-37

DOI: 10.1017/S0885715618000052

Nicola Scarlett, and Ian C. Madsen

If you can't access the paper, contact me and I'll send it.

Thank you for the comment Ian. I already requested a full text of the paper.

Yes, you are right. We may use free softwares. But, I prefer professional softwares.

dear Ural, can you please elaborate further? Being free does not mean "unprofessional"... most of the features that you find in the commercial software were first developed in the community as free tool...

Experience in this field is more important than software... and if you check the outcomes of the Reynolds cup (quantitative analysis of mineral mixtures) you see that the winners did not use any "professional softwares".. but they used either one made in house or, guess what, BGMN....

Dear all: XRD methods are able to determine the amount (%) of amorphous phases in a mixture with crystalline powders, even in presence of microabsorption like difference of 100 with the sum of crystalline contents (please, read my articles from 1986 and 1987) But the results include also the presence of indeterminable phases (below detection limit) This fact include a serious cause of error because the detection limit of many phases are poor.

Sample amorphous content is determined from the XRD pattern by the amorphicity index, which is defined as:

Ia (%) = (Aa / At) * 100 = (Aa / Ac + Aa) * 100,

where Aa represents the area of ​​the amorphous phase, Ac is the area of ​​the crystalline phases and At = Aa + Ac the total area under the X-ray diffraction pattern. The crystallinity index is similarly defined:

Ic (%) = (Ac / At) * 100 = (Ac / Ac + Aa) * 100,

It is evident that Ia + Ic = 1, and that once one of the two indices is determined, the other is determined directly from this equation.

For this purpose, as others colleages have suggested, there are different professional software that allow you to make the task, by estimating the area of amorphous phase and the area of crystalline phase. The MicrocalOrigin software has too the option of determining areas, so you can use it to determine the area under the peaks of the XRD pattern and the total area of ​​the pattern, from which you can calculate the crystallinity index and by the equation Ia + Ic = 1 determine the index of amorphicity, as well as determine the uncertainties in their measurements.

The method suggested by Jesús Eleuterio Hernández-Ruíz is correct. In almost all samples where crystalline and non crystalline phases are present the same method is applicable. It is reliable one.