TiO2-B (bronze) nanowires were synthesized via simple hydrothermal treatment of commercial titanium dioxide nanopowder in aqueous NaOH. The reaction temperature, calcination temperature, reaction time, NaOH concentration, autoclave filing fraction and precursor were systematically varied to optimize the nanowire morphology. The crystal structure, morphology and particle size were investigated by XRD, SEM and TEM. The morphology and structure are sensitive to experimental conditions. A reaction temperature of at least 150°C and NaOH concentration at least 10 M are essential, but reaction time from 24 to 72 h makes little difference. Nanowires obtained at 150°C were 60-180 nm wide and 2-4 μm long, while those after treatment at 200°C were thinner (40-100 nm) and longer (2-6 μm). The relationship between reaction conditions and morphology is discussed and practical guidelines for titanium dioxide nanowire synthesis are suggested
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Terbium doped zirconium dioxide was successfully synthesized using microwave hydrothermal method. The powder is strongly agglomerated and has mean crystallite size around 6 nm. The density of obtained powders is significantly lower than density of bulk zirconium dioxide indicating the existence of zirconium and dopant hydroxides remaining after the hydrothermal process. The effect of terbium on morphology, phase composition, specific surface area and density of the samples was determined.
Rod shaped MoO3 nanocrystals were prepared from ammonium heptamolybdate tetra - hydrate (AHM) and ethylene diamine (en) as template agent in water via a hydrothermal process at 180 graduate C. The prepared nanocrystals were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The range size of nanorods are from a few nanometers (nm) to micrometers in length and 50 to 200 nm in diameter. It was also found that nanostructures of varied dimensionality such as plates and helical plates are formed using citric acid (CA), and starch as template respectively.
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Hydroxyapatite (HA) was coated onto titanium substrates using radio frequency sputtering, and the coated HA films were crystallized in autocIave at 110°C using the low temperature hydtrothermal method. In pull-out tests, the adhesion strength of the sputtered film to the substrate increased from 1.9 : 0.2 to 5.3 : 1.6 MPa after the hydrothermal treatment. Sputtered films subjected to the hydrothermal treatment and plasma-sprayed coating on titanium columns were implanted in the diaphysis of the femora of six adult dogs, and pull-out tests were carried out after two, four, and 12 weeks. The sputtered film showed a higher bone bonding strength than the plasma-sprayed coating at the same periods. The coated implants were also placed into mandibles for 2,4, 12 and 24 weeks for histological examination. In the histological examination, connective tissue was noted after 2 and 4 weeks around the controls, whereas, in the sputter-coated implant, new bone formation was noted after 2 and 4 weeks, without any connective tissue.
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