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5519 |
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Wednesday, June 07, 2017, Hall 14 2:40 PM Medical Industry II |
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Deposition of hydroxiapatite obtained from biowaste by HVOF- and APS-processes |
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Germán Clavijo * / University of Limoges, France Jennifer Hermann/ Cinvestav Unidad Querétaro, México July Rincon/ Cinvestav Unidad Querétaro, México Astrid Giraldo/ Cinvestav Unidad Querétaro, México Helene Ageorges/ University of Limoges, Juan Muñoz/ Cinvestav Unidad Querétaro, México |
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The focus of this contribution is on the use of hydroxyapatite (HAp) from biowaste source as feedstock in thermal spray processes such as suspension plasma spray (SPS) to functionalize metallic implants with biocompatible coatings. Due to their physical characteristics bones of bovine femurs were selected as raw material to extract high quality HAp in the size range of 10 60 µm following a well-established milling, physical and chemical cleaning set of procedures. The quality of the obtained powder was verified by Rietveld refinements of X-ray pattern analysis (XRD), Fourier transform infrared spectroscopy (FTIR) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), determining the structural and chemical characteristics (phase purity, level of crystallinity, Ca/P ratio, and heavy metals content) that fulfill the requirements for biomedical applications. To prepare the feedstock suspension, HAp powder is milled to reduce the particle size and is mixed with distilled water and/or alcohol suspension. Before the powder deposition, the stability of suspension was specified by measuring its zeta potential. The suspension is deposited in preheated stainless steel substrates. The coatings surface morphology, thickness and microstructure are analyzed by scanning electron microscopy (SEM) micrographs. Moreover, XRD measurements are carried out to study the effect of SPS parameters on the HAp phase transformations seeking to avoid the formation of less biocompatible phases as TCP, TTCP, CaO and CaCO3. Finally, bioactivity in a cellular media is studied by soaking the samples in simulated biological fluid (SBF), for 3, 7 and 14 days. This bioactivity is investigated based on the dissolution of Ca-P by measuring the Ca2+ release, ICP-OES quantification and the layer of carbonate-apatite growth in the coating surface after the immersion, using XRD and FTIR analysis. |