Scherrer formula gives the information of crystallite size of the material wheather from SEM images one can only calculate the particle size.

The calculated value from scherrer formula using xrd data will be less than the particle size calculated from SEM.

Particle size > crystallite size

Regards

Hi there.

Try HRTEM instead of SEM. Your particle of 0.2 um can have crystallites grown on the surface of eachother. With the HRTEM you'll see the crystalline domains of the bigger particles, and you can try measuring them to compare with Scherrer's equation.

Thank you so much for your valuable reply and recommendations

I analyzed the data with a W-H plot and the crystallite size was larger in the second sample

I have two more questions:

1- can the growth of crystals be described as Ostwald ripening?

2- I overlapped the XRD patterns and almost the same pattern but the first sample has lower intensities ( same pattern, smaller crystals, lower intensities/counts) does this mean that the total number of crystallites increased and the crystallite sized increased as small crystals dissolved, and redeposit onto larger crystals? (Ostwald ripening)

Luiz Fernando de Sousa Lima

Sample 1&2 are of the same composition

Sample 1 exposed to one heat tx cycle

Sample 2 exposed to two heat tx cycles

Just by your XRD saying that this lower intensities are due crystallite populations is speculating. It's true that a broad and low intense peak is often related to smaller crystallites, but in your data it is hard to discuss, as one of them shows a curvature in 2Theta ]0,30]. To confirm this idea you have to do HRTEM.

To be honest, I wouldn't discuss your material in terms of Ostwald ripening, you have two experiments, I can't see how to determine if the crystall growth would follow Ostwald's equation just with two points.

The difference between samples seems to be heating, right? At what temperatures? Might be sintering instead of Ostwald ripening.

Yes, you can use both Scherrer formula and W-H plot method to calculate crystallite (D) size. Crystallite size calculated by Williamson-Hall method can be slightly higher than the crystallite size calculated using Scherrer formula.

Regards