Papers by Author: Xiao Zhan Yang

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Authors: Hong Lin, Ning Wang, Xiao Zhan Yang, Jian Bao Li
Abstract: In this paper, firstly, titanate nanotubes was synthesized by hydrothermal method with commercial antase-type TiO2 powder as the raw material. TiO2 nanotubes (TNTs) can be obtained by heat-treating the as-prepared titanate nanotubes at 400 °C. Secondly, an electrode with 30 % TNTs and 70% nanocrystalline TiO2 was designed and prepared successfully. By using the nano-electrode as the photoanode of DSC, the light-to-energy conversion efficiency of 5.42 % was obtained. In addition, the effect of hydrothermal temperature on the crystal growth of nanotubes and the effect of tert-butyl pyridine (TBP) on the photoelectric performance of the DSC were also discussed.
Authors: Ning Wang, Xiao Zhan Yang, Jian Bao Li, Hong Lin, Bo Chi
Abstract: Mullite powders of stoichiometric composition were synthesized by sol-gel process with TEOS and Al(NO3)3·9H2O as silicon and aluminum source. Homogeneous mullite powders were used as the starting materials to prepare the porous mullite coating on the porous silicon carbide support by repeated dip-coating method. XRD analysis revealed that the mullite precursor gels almost completely transformed to orthorhombic crystalline mullite at 1200°C. The average pore diameter and porosity of the porous mullite coating were about 4.5µm and 52.3%, respectively.
Authors: Gang Feng Guo, Xiao Zhan Yang, Jian Bao Li, Hong Lin, Long Liang, Ming Sheng He, Xu Guang Tong
Abstract: Silicon nitride ceramics were fabricated with Yb2O3 as the sintering additive. The effects of the amount of Yb2O3 on the microstructure and the mechanical properties such as the flexural strength and the fracture toughness were investigated. Almost fully densified Si3N4 was obtained when only 4 wt% Yb2O3 was added. Both the flexural strength and the fracture toughness increased steadily with the Yb2O3 content. The transgranular fracture mode was observed in the specimen containing 4 wt% Yb2O3, however, the intergranular fracture mode was observed in the specimen containing 10 wt% Yb2O3.
Authors: Xu Guang Tong, Xiao Zhan Yang, Jian Bao Li, Geliang Sun
Abstract: In this paper, the models of multilayer absorbing coating and hollow ball are studied. For the former model, a computer program is made to simulate absorbing results with the electromagnetic transmission line theory. The results show that there is a relevant absorbing peak at different frequencies for different dielectric constant (ε) and the apex’s height and position change with ε and thickness of the multilayer coatings. This program can predict the coating’s absorbing property efficiently. With the latter model, it is found that SiC hollow micro-balls whose porosity is about 0.89 make the best absorbing effect.
Authors: Xu Guang Tong, Jian Bao Li, Hong Lin, Xiao Zhan Yang, Jun Yang
Abstract: The effects of rare earth oxides (Lu2O3 and La2O3) on the property, microstructure and oxidation behavior of hot-pressing sintered Si3N4 ceramics were investigated. The silicon nitride ceramics with Lu2O3 and La2O3 as addition have been fabricated by hot-pressed at 1800°C for 1h under a pressure of 25MPa. Oxidation test was carried out at 1400°C in air for 100 hours. Mechanical properties, SEM and XRD were measured before and after oxidation. The results showed that Si3N4 ceramics doped Lu2O3 had good microstructure and mechanical properties than those doped La2O3. Oxidation test showed a parabolic weight gain with oxidation time at 1400°C in air and the oxidation products of the ceramics were SiO2, Re2Si2O7 and Re2SiO5 confirmed by XRD and EDS. The rate-controlling step was the diffusion of ion. The samples doped Lu2O3 showed superior oxidation resistance to those doped La2O3.
Authors: Hua Zhang Zhai, Hong Nian Cai, Xiao Zhan Yang, Jian Bao Li, Gang Feng Guo, Chuan Bao Cao
Abstract: A series of BN-SiO2 composite ceramics with high relative densities have been fabricated by hot pressing of a mixture of hexagonal boron nitride powder and silica sol. X-ray diffraction (XRD) results show that silica are distributed in the BN matrix as noncrystalline state. Microstructure of as-sintered composite ceramics is observed by scanning electron microscopy (SEM). The influence of the secondary phase on the mechanical properties is studied by varying the silica content from 10 wt% up to 40 wt%. Dielectric properties of composite ceramics are also measured from 1 MHz to 2.0 GHz.
Authors: Bo Chi, Xiao Zhan Yang, Jian Bao Li, Ning Wang
Abstract: In this paper, NiCo2O4 spinel oxide was synthesized by the oxidation of Ni-Co alloy. The variables that affect the formation of spinel oxide include the Ni-Co ratio in the alloy, the oxidation temperature and time. 350°C is the upper oxidation temperature limit. And longer oxidation time is helpful. Surface roughness analysis shows that with the formation of NiCo2O4, the surface shows rougher.
Authors: Long Liang, Jian Bao Li, Xiao Zhan Yang, Hong Lin, Ming Sheng He, Gang Feng Guo
Authors: Ming Sheng He, Jian Bao Li, Bo Wen Li, Hong Lin, Xiao Zhan Yang, Long Liang, Gang Feng Guo
Abstract: Wollastonite powder was selected as a starting material with carbonate as pore-forming agent and binder added. The porous ceramics were prepared at different temperature by sintering method. The process includes batching, granulating, pressing molding, drying and sintering. It is discussed the influence of sintering temperature, dosage of binder, dosage of pore-forming agent, pressure of molding and holding time on the performance of porous ceramics. According to the principle of particles stack, the porous wollastonite ceramics for filtration with various diameters, shapes and porosity were fabricated by serial experiments. These products have 1 to 10 microns in pore size, 30.04 to 66.15% in porosity, 2.82 m2/g in specific surface area.
Authors: Ning Wang, Hong Lin, Jian Bao Li, Xiao Zhan Yang, Luo Zheng Zhang, Yin Dou
Abstract: TiO2 nanocrystalline films were prepared by electrophoretic deposition (EPD) under a pulseperiodic electric field. The EPD behavior of TiO2 nanocrystalline suspension was investigated. The uniform 9.2-μm-thick TiO2 film was obtained by reasonably controlling the EPD condition. A dye-sensitized solar cell, with the EPD TiO2 film as the photoanode, obtained about 4.1% of photon-to-electron conversion efficiency (η). Its Jsc, Voc and fill factor (ff) are 11.6 mA/cm2, 0.65 V and 0.55, respectively. The effect of TiCl4 modification on the photovoltaic property of the solar cell was also discussed.
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