High-Performance Ceramics IV

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Authors: Xiang Peng Feng, Heng Hu Sun, Xiao Ming Liu
Abstract: The utilization of industrial solid wastes as building materials has been thought of as the best way to solve the problems caused by high waste production, high resource consumption and high pollution that is inherent with the primary industries of China. However, due to the low level of usage by previous technologies, these serious problems of the primary industries still persist. Hence, it is urgent to seek an effective way to solve these problems. In this paper, based on the understanding of the theory of simulation to formation of rock and the research advances of sialite technology, it is concluded that sialite technology can achieve the effective usage of industrial solid wastes.
Authors: Shun Li, Jia Chen Liu, Chao Liang Cui, Li Bin Liu
Abstract: Crystalline TiO2 thin films coated on silica glass fibers and nano-powders were prepared by adding H3BO3 into an (NH4)2TiF6 solution supersaturated with anatase nano-crystalline TiO2 at 40°C. The effect of the deposition conditions on the surface morphology, section morphology, growth patterns, thicknesses of the deposited TiO2 thin films were investigated. Growth rate and particle size of the thin films were controlled by the deposition conditions. As a result, a well-combined and durable TiO2 thin films on silica glass fibers surface obtained under definite optimizing experimental conditions and parameters.
Authors: Hong Li, Gao Ling Zhao, Gang Xu, Gao Rong Han
Abstract: In order to investigate the effects of doping boron on the self-cleaning properties of TiO2 thin films, sol-gel method was employed to prepare TiO2 films with various amount of boron on the glass substrates. Atomic Force Microscope (AFM) and X-ray diffraction (XRD) were carried out to investigate the effects of boron on the microstructure and crystallization behavior of the thin films. The photocatalytic activity and the hydrophilicity of the films were also measured. The results showed that the photocatalytic activity of TiO2 films was improved by doping boron, and its hydrophilicity wasn’t destroyed. This can be ascribed to the enhancement of the surface energy, which was caused by the reduction of the crystal grain size of TiO2.
Authors: Yun Yao, Li Hua Xu, Jin Qiu
Abstract: Based on the slip casting and the preparation of sialon synthesized from clay, fly ash and gangue by the carbothermal reduction nitridation, the influences of compositions, dispersant additive and sintering process on the properties of materials have been investigated in present work. The experimental results indicate that disposal of fly ash via a pickling process can greatly reduce the content of iron, and the effect is obvious with increasing the concentrations of hydrochloric acid and pickling temperature. Therefore the component of the final product can be purified. It is also noted that the final density of the sintered body using colloidal process is superior to that of using conventional dry pressing, although the slightly higher green density is observed in dry pressing body because of high compaction pressure.
Authors: Z.M. Shi, W.G. Yu, G.J. Ji, Hai Zhou
Abstract: The Ce4+-modified titania nanofilm was deposited onto mild steels by the sol-gel method. The effect of the film on protecting mild steels from oxidation was studied by means of oxidation test, SEM and XRD. It was found that the anti-oxidation effect is increased by Ce4+ modifying and with increasing layer number. When oxidized below 600 oC, the Ce4+-modified double-layer titania nanofilm possesses an excellent anti-oxidation performance that is comparable with that of the stainless steel.
Authors: A. Vantomme, A. Léonard, Zhong Yong Yuan, Bao Lian Su
Abstract: We demonstrate here a self-formation phenomenon of hierarchy with multiple-scaled porosity. Macrochanneled structures, labelled as CMI-7, with openings ranging from 0.5 to 5.0 microns and wormhole-like mesoporous walls with various ceramic compositions, such as ZrO2, TiO2, Al2O3, Y2O3, ZrO2-SiO2, ZrO2-TiO2, ZrO2-Y2O3,…, aluminosilicates, aluminophosphates, silicoaluminophosphates, metallophosphates, can be prepared by just controlling the hydrolysis and polycondensation rates of the pre-selected ceramic sources. The macrochannels (funnel-like or straight) are well parallel each other and perpendicular to the tangent of the particles’ surface. These hierarchical porous ceramics can be used in catalysis, separation and for immobilization of biological molecules and even microorganisms for filtration and bioreactor applications.
Authors: Yan Li Jiang, Hui Ling Liu, Zhao Hua Jiang, Zhong Ping Yao, Rui Hai Cui, Guo Dong Hao
Abstract: The anodized TiO2 ceramic film was post-treated by photoreduction and ion sputtering, respectively, to deposit platinum on the surface of the films. Surface morphology, the main elements of the films and platinum distribution on the film surface were investigated by scanning electron microscopy and energy dispersive spectroscopy. The phase composition of the films was examined by X-ray diffraction. The photocatalytic activity was compared through the effect of the films on photocatalytic (PC) degradation rate of the humic acid. The results showed that both films were composed of Pt5Ti3, rutile (R) TiO2 and anatase (A) TiO2, and the content of TiO2 (R) of the film prepared by photoreduction was a little more than that of the film by ion sputtering. Compared with Pt on the Pt-TiO2 ceramic film by photoreduction, Pt on the Pt-TiO2 film by ion sputtering dispersed more evenly and the grains were much smaller. Pt particulates in the film post-treated by ion sputtering were more strongly combined with the film than those by photoreduction. Besides, the PC degradation rate of humic acid by both Pt-TiO2 films were higher than that by TiO2 film, and Pt-TiO2 film by ion sputtering had higher catalytic activity and longer using life than that by photoreduction.
Authors: Wei Liang Liu, Dan Li Lu, Chang Chun Ge, Jian Hua Chen, Zhi Ping He
Abstract: La3+ and Co2+ co-doped titania nanoparticles were prepared from reacting TiOSO4, La(NO3)3 and Co(NO3)2 with NH4OH in water/Triton X-100/n-hexanol/cyclohexane microemulsions. The structure, surface morphology and the specific surface area of the samples were characterized. The photocatalytic efficiency of as-prepared TiO2 was tested by photodegrading methyl orange. The results showed that doping with La3+ and Co2+ could suppress the growth of TiO2 grains and increase the specific surface area; When the calcination temperature increased from 300°C to 900°C, the average crystallite size of the particles increased from 7.3nm to 35.6 nm andthe specific surface area of the particles decreased rapidly from 205.5m2/g to 41.2m2/g. The synthesized amorphous particles wer transformed into anatase phase at 300°C, and further into rutile phase at 900°C. UV-Vis diffuse reflectance spectrum revealed that La3+ and Co2+ co-doped TiO2 absorbed UV light and visible light, while pure TiO2 could only absorb UV light. In the experiments of photodegrading methyl orange, it was proved that La3+ and Co2+ co-doped TiO2 had high photocatalytic activity under UV light and visible light, while pure TiO2 showed photocatalytic activity just under UV light.
Authors: X.L. Jia, Y. Wang, R.S. Xin, Quan Li Jia, Hai Jun Zhang
Abstract: Rare-earth doped porous nanocrystalline TiO2 films were prepared via sol-gel method. The effect of preparation conditions on the properties of the resulting thin films, such as structure, surface topography and photocatalysis properties was analyzed. It indicated that appropriate doping of rare-earth element improves the photocatalysis ability of the thin titanium oxide films. The thin titanium oxide films have good photocatalysis properties in visible light region because of the red shift of energy level. It also revealed that uni-doped of cobalt is better than that of cobalt and lanthanum, while co-doping of cerium, cobalt and lanthanum may cause the best photocatalysis properties.
Authors: Xiao Hong Wu, Wei Qin, Xian Bo Ding, Zhao Hua Jiang
Abstract: Micro-porous TiO2 ceramic films have been grown on titanium plates by the micro-plasma oxidation method with the electrolyte of H2SO4. The influence of La3+ ion addition in the electrolyte on the photo-catalytic activities was investigated. The results showed that titanium dioxide thin films produced with La3+ addition electrolyte exhibit higher photo-activity than pure electrolyte for the oxidation of rhodamine B. The removal of rhodamine B reaches 90% for 30 min when La3+ addition concentrate is 0.05 g/L. Experimental results of X-ray diffraction and atom force microscopy show that the increase in activity is related to change in the lattice parameters and cell volume.

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