I made hydroxyapatite from mussel shells and ammonium phosphate and calcinated it after.
The diffractogram is given below and the crystallinity is calculated as follows
CI value is given by:
CI = (a(112) + b(300) + c(202))/h(211)
Using the relative intensities of the planes I202 = 24%, I300 = 58%, I112 = 57% and I211 = 100%, the calculated CI for the under-studied sample is equal to 1.39.
Could you explain why my crystallinity value is really low: 1.39%
At what crystallinity percentage should I consider hydroxyapatite of good quality for biomedical application or scaffolding?
Kindly,
Flynne
Dear Ma. Flynne Dagalea ,
from where do you have taken the CI formula?
The crystallinity CI is given by the sum of all net*) peak integrals**) divided by the integral of the total XRD pattern (i.e. peaks and background).
CI = sum of crystalline signals/(crystalline + amorphous signals)
CI is not the sum of some arbitrary peak heights divided by the height of the heighest one...
By the way: your ratio will give (57%+58%+24%)/(100%)= 1,39; and that is not 1,39%. A ratio of 1,39 is equal to 139% (%=1/100). From that value you can see, that your formula is nonsense here...
*) i.e. above the smooth background, which is assumed as the amorphous part here...
**) but not only the peak height(s)
Best regards
G.M.
Thank you Dr. Gerhard Martens, I had this crystallinity interpreted but I was hesistant to accept it. I'll try to calculate it my self.
Dear Ma. Flynne Dagalea ,
you may have for example a look at:
https://www.youtube.com/watch?v=D65k1yHPKaM
or similar tutorials...
Good luck and
best regards
G.M.
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