Crystallite size and Particle size
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A crystallite is the smallest unit of a crystal structure and forms a single diffraction pattern, while a grain can contain multiple crystallites of the same phase. Particle size refers to a single crystal or agglomeration of crystals, and is always larger than crystallite size due to multiple crystallites or grain boundaries within particles. Crystallite size is less than or equal to grain size, which is less than or equal to particle size.
Crystallite size and Particle size
- 1. Crystallite size & Particle size R.Gandhimathi
- 2. Unit Cell The smallest building block of a long-range order of a crystal Single crystal All unit cells are aligned in same direction to form a single crystal Crystallite ➢ A single crystal within a polycrystalline solid ➢ A coherent volume with a single phase corresponds to a diffraction peak of a crystalline element ➢ Forms a sharp diffraction pattern associated with that material ➢ Size of crystallite is calculated from width of diffracted line (FWHM)
- 3. ➢ A Grain contains several crystallites ➢ Smaller crystallites come closer and grow to become larger due to kinetics ➢ Grain morphology is determined by SEM Grain size
- 4. d-spacing Particle size ➢ A nanoparticle is considered as a single crystal or an agglomeration of several crystals ➢ Particle size always is larger than crystallite size ➢ Particle size and crystallite size might be same in the ultrafine nano regime Particle size crystallite <= grain <= particle One or multiple crystallite in one particle (with different orientation)
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