Communication Dans Un Congrès Année : 2022

Investigation of the microwave sintering of carbonated hydroxyapatite for bone reconstruction

Résumé

With improved solubility and biodegradation rate, carbonated hydroxyapatites (CHA) are promising bioceramics for filling bone defect compared to unsubstituted hydroxyapatite (HA, Ca10(PO4)6(OH)2). Carbonate ions in the HA lattice can substitute either for OH- through thermal treatment under CO2-rich atmosphere to form A-type CHA (CAHA) or for PO43- through synthesis by wet precipitation to form B-type CHA (CBHA). Controlling the amount and location of CO32- as well as the microstructure, which both affect the biodegradation, depends on the fabrication process and remains challenging. The sintering of CBHA is usually achieved through resistive sintering under a CO2-rich atmosphere to prevent thermal decomposition. This atmosphere causes an enrichement of A-type CO32- known to hinder densification. Sufficient consolidation thus requires high temperature or longer dwell time which may be accompanied by thermal decomposition or grain growth. To overcome these limitations, we investigate the microwave (MW) sintering which allow faster processing time. In this work, the sintering of CBHA containing 0.8 mol.% of CO32- was studied in a MW multimode cavity under air. Pellets starting from CBHA alone and from CBHA mixed with carbon powder to generate in-situ a CO2-rich atmosphere were considered. Sintering were performed at 900 °C and 1000 °C with different ramps and dwell times. Final densities were ranged between 70 and 85 % of theoretical density. From XRD and FTIR results, it was not possible to sinter a pure CBHA. With carbon, substitution of A-type CO32- appeared. The presence of carbon was thus effective for generating a CO2-rich atmosphere but insufficient, in our conditions, to avoid the decomposition. A new project that has just started will allow us to develop MW sintering under a controlled CO2-rich atmosphere. Eventually, the parts produced will be the subject of cellular and acellular biological tests.

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Dates et versions

hal-04907632 , version 1 (23-01-2025)

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  • HAL Id : hal-04907632 , version 1

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Nathalie Douard, Arnaud Le Tiec, Louis Pancrazi, Clémence Petit. Investigation of the microwave sintering of carbonated hydroxyapatite for bone reconstruction. Bioceramics32 - the 32nd Conference and Annual Meeting of the International Society for Ceramics in Medicine (ISCM), Sep 2022, Mestre, Italy. ⟨hal-04907632⟩
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