Glass Research Division, Institute of Glass and Ceramic Research and Testing, Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhaka, Bangladesh
This paper reports a detail crystallographic investigation of a well-known biphasic biomaterial containing hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP). This biphasic calcium phosphate bioceramic (BCP) was synthesized by three typical methods: (i) solid-state method (where CaCO3 and (NH4)2HPO4 was the source of Ca and P, respectively); (ii) wet chemical method (where the reactants were Ca(OH)2 and H3PO4); and (iii) direct incineration of bovine bones. Furthermore, the adopted fourth method to synthesize the biphasic biomaterial was UV irradiation instead of high temperature calcination. In each case the synthetic biphasic biomaterial was characterized by employing X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) techniques. Various crystallographic parameters such as crystallite size, dislocation density, microstrain, crystallinity index (from XRD and FT-IR), HAp percentage, β-TCP percentage, the volume fraction of β-TCP, and degree of crystallinity were estimated by conventional approaches for the broader applicability of this biphasic biomaterial. Two new models for measuring microstrain and one new method (XRD-sin2Ѱ technique) for calculating residual stress (also known as intrinsic stress) were developed to estimate the crystallographic parameter more accurately. A linear relationship was illustrated among the value of conventional methods and newly developed techniques without significant difference (R2 = more than 0.9) among the values of four types of HAp.