Effect of Hydroxyapatite on the Properties of Wollastonite Bioceramics

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Author(s) Shaker Jahil Edrees | Majid Muhi Shukur | Oula Saleh Mahdee
Pages 322-328
Volume 5
Issue 6
Date June, 2015
Keywords Hydroxyapatite; Wollastonite; Bioactivity; Biocomposite ; Solid State Reaction Method; SBF.

Abstract

Replacement for worn or injured body parts is the area wherein biomaterials are predominantly used. In the research, we have developed compact of hydroxyapatite-wollastonite for bone implant applications. The effect of crystalline hydroxyapatite amount on the mechanical, physical, and biological properties for the prepared biocomposite material was evaluated. The wollastonite matrix was synthesized by solid state reaction method from its constituent e.g. CaO, which prepared from natural source belong to oyster shells by calcinations at 900◦C for 1 hour, and high purity silica foam. The silica foam and calcium oxide powders were mixed in 1:1 molar ratio then sintered at 1300 ◦C for 2 hours. The prepared wollastonite was mixed with different weight percent's of hydroxyapatite (10, 20, 30, 40, and 50 %). Hydroxyapatite-wollastonite samples were prepared by cold pressing at (200MPa). The compacts prepared from powders of (hydroxyapatite-wollastonite), sintered at1100◦C and 1200◦C for 3 hours. The microstructures for the prepared samples are investigated employing XRD and SEM technique. The biological properties of the ceramics samples were examined by immersion of the prepared samples in the stimulated body fluid solution. The interaction of these materials with an SBF produces bonelike apatite layer on their surfaces, which is thicker when the hydroxyapatite is in a higher proportion. The variations in ionic concentrations of Ca and Si demonstrate that the dissolution of the material surfaces with a simultaneous took place during the soaking tests, being slightly faster on 100W, 20H–80W, and 50H–50W, respectively. This could be due to the fact that the dissolution rate of the wollastonite phase was higher than that of the hydroxyapatite phase in SBF solution. The best results are obtained at 1100 °C and 1200°C for samples contained 30%HAP, due to good biological, mechanical, and physical properties compared with the pure HAP, and the prepared wollastonite .The physical properties of prepared samples (porosity, firing shrinkage) were tested. The results showed enhancement in the physical properties of hydroxyapatite/wollastonite sample.

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