Papers by Keyword: Synchrotron Radiation Diffraction

Abstract: Residual stress has large effect to the service life of biomedical ceramic coatings. It is therefore important to characterize it precisely. Since in-service damage of the prostheses is generally characterized by cracking of the substrate layers located close to the metal / ceramic interface, our study was focused on these particular zones of the parts. High energy synchrotron radiation diffraction techniques were therefore developed to evaluate the residual stress profiles of the metal / ceramic interfaces. The method requires, however, defining precisely the true position of the X-ray probe inside the materials. A complete modeling of the instrument, using a ray tracing Monte Carlo simulation method, was developed for that purpose. Fourier analysis of the diffraction peaks was also implemented to evaluate the micro stresses of second and third kind. These diffraction techniques were tested on a glassy ceramic coating used for the manufacturing of dental prostheses.

Abstract: The oxidation behaviour of Ti3SiC2 in air is not well understood due to mixed results reported in the literature. In this study, the surface composition depth-profiles of air-oxidized Ti3SiC2 have been investigated by synchrotron radiation diffraction (SRD) and secondary ion mass spectroscopy (SIMS) in the temperature range 500-1300°C. Anatase has been observed to form at ~600°C, rutile at ~750°C and tridymite at ~1100°C. Depth-profiling results by SIMS and SRD have revealed a distinct gradation in element and phase composition respectively within the surface oxide layers.

Abstract: Structure-property relationships in bovine cortical bone have been characterised using grazing-incidence synchrotron radiation diffraction, Vickers indentation and mechanical testing. Depth profiling results indicated the existence of distinct gradual changes in crystal disorder, phase abundance, and texture of hydroxyapatite whilst the crystallite size was depth-independent.

Abstract: Structure-property relationships in baby and adult teeth have been characterised using grazing-incidence synchrotron radiation diffraction and Vickers indentation. Similarities and differences between both types of teeth have been highlighted and discussed. Depth profiling results indicated the existence of contrasting but distinct gradual changes in crystal disorder, phase abundance, crystallite size and hardness within the baby and adult canine enamel, thus confirming the graded nature of human teeth. When compared to the adult tooth, the baby enamel is softer, more prone to fracture, but has larger hydroxyapatite grains.