STP1196: X-Ray Diffraction Method for the Quantitative Characterization of Calcium Phosphate Coatings

    LeGeros, JP
    Director of TechnologyAssoc Prof., Hitemco Medical Applications, Inc.New York University College of Dentistry (NYUCD), Old BethpageNew York, New YorkNew York

    LeGeros, RZ
    Professor, Calcium Phosphate Research Laboratory, NYUCD,

    Burgess, A
    Research Scientist, Calcitek, Inc., Carlsbad, CA

    Edwards, B
    Principal Research Engineer, Howmedica, Inc., Rutherford, New Jersey

    Zitelli, J
    Manager, Howmedica, Inc., Rutherford, New Jersey

    Pages: 10    Published: Jan 1994


    Abstract

    An X-ray diffraction (XRD) method was developed to quantify the crystallographic character of coatings for implants in terms of phases present and amount of amorphous calcium phosphate or micro-crystalline phases included. This method requires only information from the Joint Committee for Powder Diffraction Standards (JCPDS) files, does not require the use of admixed standards, and automatically takes into account and corrects for the variations in crystallite sizes of component phases. This method employs an algorithm based on real XRD optics and not a statistical fit. The residual information from convoluted peaks after defining one or more of them using the algorithm gives the basic data for further deconvolution of any remaining peaks and a quantitative assessment of the phases present which they represent. Usually an explanation of variance greater than 95% is achieved for the deconvoluted modeled profiles. The method is robust. The overall deconvolution of the peaks of all crystalline phases present from the total XRD profile gives the profile and quantification of any amorphous or micro-crystalline phase present. The reliability of this method was demonstrated by analyses of admixtures from three different laboratories and comparison of results on the same coatings from two different laboratories.

    Keywords:

    coatings, x-ray diffraction, hydroxyapatite, amorphous calcium phosphate, deconvolution


    Paper ID: STP25181S

    Committee/Subcommittee: F04.13

    DOI: 10.1520/STP25181S


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