Dear Yinebeb Teferi ,

there is no relation between the crystallite size (apart from crystallite size being zero) and crystallinity. Crystallinity is a relative measure of the crystalline content in a sample. The counter part is the relative amorphous content.

You may have a look at the answers of a similar question here on RG:

https://www.researchgate.net/post/Is_there_any_relationship_between_the_crystallite_size_and_crystallinity_of_a_semicrystalline_sample

Best regards

G.M.

thank all.