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XRD nano-hydroxyapatite

  1. Sep 23, 2009 #1


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    I would like to ask your help in the interpretation of Xrd data from hydroxyapatite nanopowder.
    I know from the start that powders which I am analysing are already crystalline (another techniques were used to confirme that) but I keep having a characteristic spectrum of amorphous hydroxyapatite.
    Why does this happen? What´s the influence of crystal size during in XRD procedure?

    Thank you !
  2. jcsd
  3. Sep 23, 2009 #2
    A small crystal size will induce a broadening effect of the Debye rings. This relationship is discribed by:


    B = broadening of diffraction line measure at FWHM
    t = crystal size diameter

    B is the broadening of the peak due to grain size alone, therefore you must correct for the specific machine, do this using a large grained standard (of the same material).

    B2 = BM2 - Bs2
    Where BM is the measured breadth of the diffraction line and Bs is the measured breadth of the of the standard line.

    I hope this helps, all this info can be found with much better explanation in:

    Elements of X-Ray Diffraction, 2nd Edition, B.D. Cullity
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