Materials Science Forum Vols. 544-545

Abstract: Colloidal silica/methyltrimethoxysilane (MTMS) sol solutions were prepared in variation with the ratio of MTMS to colloidal silica. Sol solutions were prepared by sol-gel reaction. To understand their physical and chemical properties, dip coating of sol solutions was performed on the glass substrates. The state of coating films was investigated in variation with the amount of MTMS and reaction time. The contact angle and thickness of coating films increased with an increasing amount of MTMS. The surface roughness of coating films decreased with an increasing amount of MTMS. Coating films were stable until 550°C. Thermal degradation temperature of coating films decreased with an increasing amount of MTMS.

Abstract: Several sol solutions were synthesized by using two kinds of nanosized boehmite and methyltrimethoxysilane (MTMS) according to the changing amount of MTMS at different reaction time. To understand their physical and chemical properties, sol-gel coating films were fabricated on glass. The sol solutions were prepared from boehmite of spherical shape (boehmite1)/MTMS and mixed boehmites of spherical and fibrous shapes (boehmite2)/MTMS. The soluble stability of boehmite1/MTMS was observed in the sol solution left for 24 h, however, that of boehmite2/MTMS was observed in the sol solution left for 48 h. The contact angle of sol-gel coating films from boehmite/MTMS increased with MTMS contents and reaction time. The films formed a flat surface with the increasing MTMS contents and decreasing reaction time. The electrical resistivity of films increased with MTMS contents. The thermal degradation of films occurred at approximately 400 oC.

Abstract: Recovery process of Ni from anode materials of spent Ni-MH batteries and application of the resulting Ni to CH4 dry reforming catalyst were investigated, focusing on availability of Ni. NiO, which formed a solid solution with CoO, was successfully prepared from the waste by a series of chemical processes using aqueous solutions of HCl and NH3. The resulting NiO, which was reduced to Ni0, exhibited excellent CH4 conversion in CH4 dry reforming. From
results, it was concluded that the Ni recovered from anode materials of spent Ni-MH batteries was available for CH4 dry reforming catalyst.

Abstract: Solid polymer electrolytes (SPEs) based on poly (vinyl alcohol) were prepared with dimethyl sulfoxide as a solvent. Prepared SPEs form the 'fast cationic transport process' and lithium ion hopping through 'fast cationic transport process' is occurred. In this study, we observed the dependence of ionic conductivity on the drying time of solvent and there was particular relationship between ionic conductivity and the amount of residual solvent. Especially, we investigated the influence of solvent on cation mobility in the ‘fast cationic transport process’ and we found that the solvent acted as a bridge to connect neighboring ion aggregates and made the ion hopping easy.

Abstract: In order to prevent the irreversible collapse of the silica aerogel backbone upon the drying of the liquid phase of silica wet gel derived from water glass based silicic acid, we tried to strengthen the aerogel back bone by aging silica wet gels in water and TEOS/ethanol solutions. Although aging of silica wet gels in water has been shown to grow the neck between silica particles of the aerogel backbone, it is hard to obtain a crack-free aerogel monolith. On the other hand, the mechanical stability of silica aerogels was improved significantly by aging the wet gel in TEOS/ethanol solutions with different TEOS content.

Abstract: Si film electrodes for Li micro-film batteries were fabricated on a Cu substrate and a Ci/Cu film. In the structural properties, FE-SEM observation demonstrated difference in surface morphologies of Si films with different under layers. Surface of the Si film deposited consists of clusters and average size of the cluster was 165 nm for Si/Cu film and 80 nm for Si/C/Cu film. Si film has amorphous phase in spite of different under layers; Cu substrate and C/Cu film. In the electrochemical properties, the carbon-inserted film showed a good cycleability compared with Si/Cu electrode. It is believed that the insertion of carbon film as a buffer film absorbed the stress generated during charge-discharge process and improved cycle performance of Si anode electrode.

Abstract: The ferroelectric properties of UV irradiated and non-irradiated SBT thin films using photosensitive starting precursors were investigated. The observation of surface microstructure showed that UV irradiation and increase in anneal temperature induced the grain growth of SBT. The measured remnant polarization values of UV irradiated and non-irradiated SBT films after anneal at 700oC were 5.8 and 4.7 )C/cm2 and after anneal at 750oC, the values were 10.8 and 9.3 )C/cm2, respectively.

Abstract: A series of sulfonated poly(aryl ether ketone)s were prepared by condensation polymerization with bisphenol A and 1,2-bis(4-fluorobenzoyl)-3,6-diphenylbenzene, and followed by sufonation with chlorosulfonic acid. The polymers were characterized by Fourier transform infra-red (FTIR) and ion exchange capacity (IEC) to verify sulfonation. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were carried out to investigate the thermal stability of the prepared membranes. The membranes were found to possess all the requisite properties; Ion exchange capacity (3.31meq./g), glass transition temperatures (207-230°C), and low affinity towards methanol (2.04x10-6-4.15x10-7 cm2/S).

Abstract: The ultrasonic spray pyrolysis method and proper heat treatments were applied in order to synthesize La0.8Sr0.2CrO3 (LSC) which is one of promising materials for separator in soild oxide fuel cell in this study. LSC powders that were sprayed at 800oC, heat-treated at 900oC for 5 hrs, ball-milled and finally heat-treated again at 1200oC for 20 hrs showed the average diameter of 0.3 *m and narrow size distribution to find particles above 0.5 *m hardly. In addition, the synthesizing temperature of LSC powders in ultrasonic spray pyrolysis method was 100
lower than conventional ball milling and drying method. Therefore the proper combination of heat treatment and milling process after spray pyrolysis was found to be very critical in synthesizing fine and uniform LSC powders. Finally, the sintering properties of these LSC powders were analyzed and compared with those of conventional ones.

Abstract: The nickel sulfide (Ni3S2) thin film could be prepared from Ni/S double layer, which was deposited on nickel foil using evaporation and sputtering. The nickel sulfide electrode was discharged and charged between 0.6V and 2.6V versus Li/Li+ at room temperature. The nickel sulfide film had the first discharge capacity of 270mAh/g, and two plateaus at 1.3V and 1.8V.