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Rapid, accurate phase quantification of multiphase calcium phosphate materials using Rietveld refinement
Author(s) -
Hendry Jason A.,
Reid Joel W.
Publication year - 2006
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889806020395
Subject(s) - rietveld refinement , materials science , calcium , lattice constant , phase (matter) , analytical chemistry (journal) , accuracy and precision , chemistry , phosphate , crystallography , mineralogy , crystal structure , diffraction , chromatography , mathematics , metallurgy , physics , statistics , organic chemistry , optics
Rietveld refinement has been employed to estimate the crystalline phase compositions of multiphase calcium phosphate mixtures containing calcium hydroxyapatite [Ca 5 (PO 4 ) 3 OH], and alpha and beta tricalcium phosphate [Ca 3 (PO 4 ) 2 ]. Two methods were employed using fixed structural models for all three phases and refining the zero offset, scale factors, lattice parameters and one peak breadth parameter using either a constant background (method A) or a background with two refined parameters (method B). Analysis of a matrix of quantitative standards across a broad spectrum of phase compositions indicates that method A results in small systematic deviations of the Rietveld phase compositions (< 1 wt%) from the nominal values, but the systematic deviations are eliminated by refining the background (method B). The methods require approximately 10 min to complete, and are suitable for quality control of calcium phosphate production (and potentially other multiphase systems) when accuracy, precision and time are all significant considerations.