Determination of the Bone Mineral Crystallite Size and Lattice Strain from Diffraction Line Broadening

Diffraction line broadening observed for the biological apatite is ascribed to small crystallite dimensions and lattice imperfections. However, it is rather difficult to separate the individual contribution of each factor. Therefore in numerous works a total inverse width of a diffraction peak is only used as a size/strain parameter. Several authors determine the bioapatite crystallite size ignoring the lattice strain. As is shown in the present paper, this problem can be resolved for oriented specimens. The crystallite size and lattice strain were calculated by two independent methods: Fourier analysis and approximation with threefold convolution of X-ray lines. The approach proposed can be useful in the investigations into structural aspects of the bone apatite and its synthetic analogues as the crystal size is related to surface defects and the lattice strain to lattice imperfections.