Structure and Biocompatibility Analysis of Sol-Gel Prepared Niobium and Titanium Oxide with Temperature
Date
2012-06
Authors
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New York State College of Ceramics at Alfred University. Kazuo Inamori School of Engineering.
Abstract
Niobium and titanium oxides were prepared via the sol-gel technique. The
structural evolution of these oxides with calcination temperature (150-650oC) was
investigated using differential thermal analysis (DTA), high temperature x-ray diffraction
(HTXRD), and Raman spectroscopy. The phase transformations of the niobium oxide as
a function of calcination temperature were as follows; amorphous to hexagonal (~500oC)
and hexagonal to orthorhombic (~600oC). The crystallite size increased from 23 to 74
nm. The titanium oxide remained amorphous to 325oC until crystallization to the
tetragonal anatase phase at ~350oC, and remained so until 650oC. The anatase crystallite
size increased from 22 to 45 nm. The lattice parameters and cell volumes for both
niobium and titanium oxides were determined using the Rietveld method from which the
linear and volume thermal expansion coefficients were calculated respectively. Raman
spectroscopy was used to further characterize the structure of these oxides and both band
position and shape were strongly dependent on calcination temperature, with overall
results consistent with HTXRD.
A series of selected oxide compositions and structures including; TiO2-amorphous
(275oC), TiO2-tetragonal (500oC), Nb2O5-amorphous (450oC), Nb2O5-hexagonal (525oC),
and Nb2O5-orthorhombic (650oC), were then selected for bioactivity testing using
simulated body fluid (SBF) analysis. Bioactivity was determined through the analysis of
calcium phosphate formation at the surface of selected oxides as a function of SBF
reaction time, as observed under Scanning Electron Microscopy (SEM) and Energy
Dispersive X-Ray Spectroscopy (EDX). It was shown that bioactivity was a function of
crystallinity, as TiO2-tetragonal (500oC), and Nb2O5-hexagonal (525oC) were the only
oxides which exhibited bioactivity.
Description
Advisory committee members: Matthew Hall, Scott Misture. Dissertation completed in partial fulfillment of the requirements for the degree of Masters of Science in Materials Science and Engineering at the Kazuo Inamori School of Engineering, New York State College of Ceramics at Alfred University
Type
Thesis