Synthesis and Sintering-wet Carbonation of Nano-sized Carbonated Hydroxyapatite

Study of biomorphic calcium deficient hydroxyapatite fibres derived from a naturalHarakeke(Phormium tenax) leaf fibre template

The complex structure of natural bio-organic matter has inspired scientists to utilise these as templates to design 'biomorphic materials', which retain the intricate architecture of the materials while acting as a useful bioactive material. Biomorphic hydroxyapatite-based fibres were synthesised usingHarakekeleaf fibre as a template, which constitutes a powerful method for manufacturing bioactive ceramic fibres. Furthermore, in creating the hydroxyapatite-based fibres, a natural source of calcium and phosphate ions (from bovine bone) was utilised to create the digest solution in which the leaf fibres were immersed prior to their calcination to form the inorganic fibres. Chemical, thermogravimetric and microscopic characterisation confirmed that the final product was able to successfully replicate the shape of the fibres and furthermore be transformed into calcium deficient, bone-like hydroxyapatite.

Multi-Analytical Characterization of Corvins’ Castle—Deserted Tower. Construction Materials and Conservation Tests

The aim of this paper is to analyze the construction materials (mortars) of an architectural monument (Deserted Tower (Lilly Tower) from Corvins’ Castle, Romania). The mortars were characterized following a multidisciplinary approach, combining macroscopic observation with petrographic microscopy, mineralogical analysis (X-ray diffraction) and elemental analysis (X-ray fluorescence), hydric properties, and color of representative samples of the monument. The results revealed the use of gypsum mortars (produced by lumps with higher Fe content), with minor concentrations of crystalline dolomites of the Southern Carpathians, calcite, and quartz. The materials’ effective porosity and their water absorption capacity were high. A possible solution to consolidate the damaged area with some consolidation products (hydroxyapatite carbonate and its derivatives with Ag and Sr) was investigated, too. The interactions between the mortar’s specimens and the effectiveness of the consolidation treatments were evaluated by physico-chemical analyses (molecular structure by X-ray powder diffraction (XRPD), wavelength dispersive X-ray fluorescence (WDXRF), dynamic light scattering (DLS)), morphological characterization by microscopic techniques as SEM-EDS, TEM, and physical and mechanical investigations (peeling test and compressive strength). Results were drawn based on historical, in situ observations, and analytical data, and put into evidence the composition, high weathering degree, and the possibility to surface consolidate with Sr-CHAp.