Are crystallite size and particle size are the same?
If not, then how can particle size be calculated from XRD data?
Google your question in combination with Resarchgate and you get numerous questions on the same subject with for instance the following title
Can anyone clarify the difference between Grain size, particle size and crystallite size?
What is the difference between crystallite size, grain size, and particle size?
What is the relation among crystallite size, grain size and particle sze?
What is particle size, crystalline size, grain size?
Why is there a difference in the crystalline size of the nanoparticle as measured from TEM image and XRD analysis of the same sample?
As Harry ten Brink already mentioned there are already several questions touching this topic. Nevertheless, a short answer.
As the terminology already explains a particle is assymed to be a homogeneous object, but it can consist of many subobjects like crystals of the same or different phases, amorphous as well as crystalline. A crystallite however is a single-crystalline individuum of a very small size. Crystal and crystallite are terms expressing the somehow the same. The later only points out that the (small) size of a specific characteristic.
Thanks Gert Nolze.
Hi Harry Ten Brink, simply my question is how we can find the particle size via XRD?
As far as I know, you cannot find the particle size by XRD but only the average crystallite size applying the Scherrer equation. If you have a bulk material (e.g. a ceramic or metallic sample) consisting nano-crystals, it is practically a "single particle" which size you cannot determine.
average crystallite size using the Scherrer equation and particle size from TEM image.
one always calculates by scherrer formula only the 'coherently scattering crystallite size' in xrd analysis...
@ last replyers
Notice that this question is 4 years old
In the mean time this question has been asked by others another hundred times and answered by thousands
You can check via google
enter
researchgate &
crystallite size and particle size
XRD studies only gives the crystalline size not the particles size. In order to determine the particles size, TEM or DLS studies are usefull.
The simple answer can be as follow:
Particle (agglomeration of some grains) => Grain (ensemble of some crystallites and sometimes consists of a single crystalline material) => Crystallite (is the smallest and can be mono- or poly-crystalline)
One can consider crystallite and grain size to be approximately the same. It is important to note that a grain consists of a single material, but maybe crystalline, or polycrystalline.
For a complete characterization, you may need to use a TEM with additional analytical tools. But you can distinguish single-crystal grains from polycrystalline grains by switch the mode to diffraction: a single crystal grain will form a sharp diffraction pattern associated with that material, the transform of the crystal structure, while the polycrystalline grains will have multiple copies of the pattern, perhaps even rings. When you get to the particle size, it is always the largest, and may consist of several grains, and perhaps even grains of different materials. You will spend some time with your local microscopists in order to complete the characterization.
The average crystallite size can be determined using the Scherrer equation, the grain morphology is commonly determined by SEM, and the particle size can be estimated from TEM image.
Also please note that Sherrer's formula is an approximation, and works best for nearly spherical particles. You will obtain the best results from TEM or AFM, especially for very small, or irregular shapes.
The crystals form the particles, that is mean the crystals inside the particles
- Badges
- Science method
- Similar topics
- Methodology
- Crystallography
- X-ray Diffraction
- XRD Analysis