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Effect of Processing Temperature on the Properties of Nanophase Fe-substituted Hydroxypatite
| Title: | Effect of Processing Temperature on the Properties of Nanophase Fe-substituted Hydroxypatite. |
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| Name(s): |
Kathriarachchi, Vindu, author Leventouri, Theodora, Thesis advisor Florida Atlantic University, Degree grantor Charles E. Schmidt College of Science Department of Physics |
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| Type of Resource: | text | |
| Genre: | Electronic Thesis Or Dissertation | |
| Date Created: | 2015 | |
| Date Issued: | 2015 | |
| Publisher: | Florida Atlantic University | |
| Place of Publication: | Boca Raton, Fla. | |
| Physical Form: | application/pdf | |
| Extent: | 149 p. | |
| Language(s): | English | |
| Summary: | The effect of processing temperature on the crystal structure properties of the Fe-substituted Hydroxyapatite (Fe-HAp) was studied by using the Rietveld refinement method of powder x-ray (XRD) and neutron diffraction (NPD) patterns. Superconducting QUantum Interference Device (SQUID) magnetometry, transmission electron microscopy (TEM) and x-ray fluorescence spectroscopy (XRF) were used to study the magnetic properties, particle morphology and chemical composition of the prepared samples. Two sets of samples of chemical formula Ca5-xFex(PO4)3OH were prepared with x = 0, 0.05, 0.1, 0.2 and 0.3 by using processing temperatures of 37°C and 80°C, following a two-step co-precipitation method. A single phase HAp was identified in samples with x = 0 and 0.05. Processing temperature affects the type and percentage of secondary phases: hematite was detected in samples prepared at 37°C with x ≥ 0.1, hematite and maghemite were detected in samples prepared at 80°C with x = 0.2 and 0.3. Rietveld refinements of NPD and XRD patterns showed that the a lattice constants are greater in Fe-substituted samples prepared at 37°C, whereas the c lattice constants are greater in the 80°C samples for x ≥ 0.05. Fe preferentially substitutes at the Ca2 site in the 80°C samples, whereas Ca1 is the preferred substitution site in the 37°C samples. Fe substitution results to a decrease of the lattice constants at both preparation temperatures. The ratios Fe/(Fe + Ca) of the refined atomic fractions of the samples prepared at 80°C are greater than those of the 37°C samples. Further, more secondary phases form in samples prepared at 37°C compared to 80°C samples. The magnetic measurements reveal that pure HAp is diamagnetic, whereas samples with x = 0.05 and 0.1 are paramagnetic. Samples with x = 0.3 showed superparamagnetic behavior based on ZFC and FC measurements. Similar hysteresis loops in samples x = 0.2 and 0.3 indicate that the samples with x = 0.2 may show superparamagnetic properties. For x = 0.2 and 0.3, the samples prepared at 80°C showed higher magnetization compared to the 37°C samples, because of the maghemite secondary phase. Based on the TEM images, Fe substituted HAp nanoparticles prepared at 37°C are mainly spherically shaped, and the 80°C particles are mainly elongated. Increase of the Fe concentration favors formation of elongated particles and larger spherical particles. The XRF measurements confirm the Fe for Ca substitution in the HAp structure based on the decrease of the Ca/P and the increase of the Fe/(Fe + Ca) atomic ratios with the Fe concentration. | |
| Identifier: | FA00004512 (IID) | |
| Degree granted: | Dissertation (Ph.D.)--Florida Atlantic University, 2015. | |
| Collection: | FAU Electronic Theses and Dissertations Collection | |
| Note(s): | Includes bibliography. | |
| Subject(s): |
Biomedical materials Nanostructured materials -- Environmental aspects Nanostructured materials -- Mechanical properties Pharmaceutical biotechnology Rietveld method |
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| Held by: | Florida Atlantic University Libraries | |
| Sublocation: | Digital Library | |
| Links: | http://purl.flvc.org/fau/fd/FA00004512 | |
| Persistent Link to This Record: | http://purl.flvc.org/fau/fd/FA00004512 | |
| Use and Reproduction: | Copyright © is held by the author, with permission granted to Florida Atlantic University to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder. | |
| Use and Reproduction: | http://rightsstatements.org/vocab/InC/1.0/ | |
| Host Institution: | FAU | |
| Is Part of Series: | Florida Atlantic University Digital Library Collections. |
