Key Engineering Materials Vols. 368-372

Abstract: Silver nanoparticles doped glass composites were prepared by ion-exchange and subsequent thermal treatment processes. The optical properties of silver nanoparticle-glass composites were investigated by UV-VIS spectrophotometer and z-scan technique. The results show that the optimal Ag+/Na+ ion-exchange temperature range is between 310°C and 380°C, higher ion-exchange temperature or higher AgNO3 concentration in melt or longer ion-exchange period favors the introduction of more Ag+ ions into soda lime silicate glasses. The higher Ag+ concentration introduced into silicate glass, the larger the volume fraction of Ag nanoparticles in glass after annealing will be. Ag nanoparticles size and volume fraction become larger with increasing the annealing temperature and extending the annealing time. The off-resonant third-order nonlinear optical susceptibility of Ag nanoparticle-glass composite exhibits a value of 1.16×10-10esu where the real part is -1.15×10-10esu, and imaginary part is 1.4×10-11esu.

Abstract: The electrical properties of 10M2O-36Fe2O3-54P2O5 (M=Li, Na and K) glasses were studied in the temperature range from 323 to 573 K. Non-linear Arrhenius behavior was observed for all the samples examined. It was shown that in both high- and low-temperature ranges, the replacement of Li, Na and K would result in decreases in both the dc conductivity and the activation energy. Analysis of the relationship of the parameters included in the Arrhenius equation, activation energy and the pre- exponential factor for each sample, preliminary explanations for these experimental phenomena have been presented.

Abstract: Lithium phosphate glass with composition of 45Li2O-55P2O5 (in mol%) was prepared by the conventional melt quenching method and the electrical properties were examined by DC conductivity and impedance spectra. It was found that the difference between DC conductivity and DCtot conductivity deduced from impedance spectra was distinct. Difference of activation energies obtaining by DC and DCtot conductivity implied that the conduction mechanism was different. The glass of 45Li2O-55P2O5 is lithium ion conductor while the oxygen ion in the glass can migrate in some conditions.

Abstract: This work is to compare the electric conductive activation energies with increasing Na2O in SiO2 and B2O3 glasses. The electrical conductivity is measured by TER2000 analyzer and it is compared with value calculated by Arrhenius equation. The conductivity of SiO2 system glasses is higher than B2O3 system glasses, and the highest value is 1.36 × 10-4 cm-1 in 60SiO2-40Na2O glass. The activation energy from conductivity is proportion to temperature and inverse proportion to Na2O contents. The activation energy is analyzed from density and CTE (thermal expansion coefficient).

Abstract: The sol-gel derived bioactive glass short fibers in the system CaO-P2O5-SiO2 was prepared using air-spray method. SBF immersion test indicated that the fibers possessed satisfactory bioactivity. SEM, XRD, FTIR analysis revealed that the morphologies and bioactivity of the fibers could be significantly influenced by the composition and viscosity of the solution. The fibers are very promising biomaterials for applications to bone restoration and tissue engineering as the bone defects fillers or additives for strengthening of the biomedical polymers.

Abstract: The purpose of this study is doing analogical inference of characteristic of glass by using the critical disconnect bonding and verifies this equation is proper or not to predict the property of matter when a laser is induced to glass substrate. As starting composition, 10Na2O-10CaO-xB2O3-(70-x)SiO2 glasses (x= 10 ~ 25) were used and Nd:YAG laser(532nm) was applied to make a microstructure onto surface. Followed to the portion of B2O3 is increasing the bonding strength was increased. As the result bump size was decreased at the same laser fluence. The minimum size of the bump was about 1.3μm at 328J/cm2 laser fluence. This size is similar pitch size compared with commercial polycarbonate CD.

Abstract: Nanocrystalline titanium dioxide was synthesized by microwave hydrothermal (MH) using tetrabutyl titanate and normal butyl alcohol as start materials. The mixture solution of tetrabutyl titanate and normal butyl alcohol in 1:1.5 molar ratio was processed in a microwave hydrothermal digestion system at 200oC for 20 min to prepare nanosized TiO2 powders. The results showed that the microwave assisted reactions proceed at a faster rate than the traditional hydrothermal methods. The powder was heat treated at 500oC and the final products is ~20 nm in size and well dispersed.

Abstract: Layered potassium titanate is an important intermediate in preparing titania nanosheets. Three methods including method of potassium stearate, method of stearic acid and method of high-temperature solid-state reaction were used to produce layered potassium titanate in this paper. XRD and SEM were used to characterize the crystal structure and shape. The result of experiments showed that method of potassium stearate was the most effective way to prepare the layered potassium titanate.

Abstract: Titanium dioxide (TiO2) thin film on glass substrate is fabricated by sol-gel method. The TiO2 film is sintered at various temperatures for investigation on the refraction index and crystallization characteristic. The lower refractive index of the TiO2 thin film is 1.89 when the sintering is performed at the low temperature of 200°C and the thickness is 448 nm. However, the higher refractive index of 2.55 and chemical stability of the TiO2 film in rutile phase are obtained via sintering temperature at 700°C.

Abstract: Preparation of titania films by pyrolysis of chelated tetrabutyl titanate was investigated. Films of tetrabutyl titanate were first formed on glass substrates by spin coating, and TiO2 films were prepared after annealing at 500°C. The influences of annealing temperature, AcAc concentration, Ti(OBu)4 concentration, PEG amount and coating times on the photocatalytic properties of TiO2 films were studied, and the films were characterized by XRD and DTA.