Papers by Author: Dan Yu Jiang

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Authors: Qiang Li, Dan Yu Jiang, Ya Jun Fan, Cheng Zhang
Abstract: This paper reports a novel non-aqueous solvent chemical process to prepare nano ZrO2 powders. ZrOCl2•6H2O and urea were directly dissolved into an organic solvent of glycol. After this solution was put into an oven and reacted at 950C for 2 h, a transparent gel was obtained. As-received gel was heated at 2100C for 5 hrs to remove glycol, and dry powders were obtained. Then the powders were calcined at 7500C, and monoclinic phase of ZrO2 was obtained. With different concentration of ZrOCl2, a range of nano ZrO2 powders were obtained. Furthermore, a surfactant of polyglycol was added into the solution to improve the dispersion of nano-particles in the gel. XRD analysis confirmed the monoclinic phase of ZrO2. SEM imaging showed the characteristics of nanoparticles. BET analysis was employed to test the aggregation of as-received nano ZrO2 particles. Considering the effects of both the concentration of ZrOCl2 and the surfactant, the optimized synthesis process of nano ZrO2 particles was formed.
Authors: Cheng Zhang, Qiang Li, Dan Yu Jiang
Abstract: This paper reports a novel route to synthesize nano particles of YAG:Ce3+ luminescent materials via polymer gel precursor. In an aqueous solution containing Y(NO3)3, Ce(NO3)3 and Al(NO3)3, citric acid was added to improve the stability of the solution. Then, acrylamide and N,N`-methylenebis- acrylamide were added. The polymerization of mixture solution was initiated by adding (NH4)2S2O8. By heating the solution at 80oC for 3 h, a transparent gel was obtained. The gel was firstly transformed into active carbon by soaking it at 700oC in ultrahigh pure N2 atmosphere. Carbon in as-received mixture was then removed when the atmosphere was changed from nitrogen to air at the same heating temperature. Well dispersive nano powders of single phase YAG:Ce3+ were thus obtained. XRD, SEM and BET were used to study the characteristics of as-prepared nano YAG:Ce3+ powders.
Authors: Chang Tian Huan, Jin Feng Xia, Dan Yu Jiang, Qiang Li
Abstract: This paper compares the low-temperature aging performance of 5Y-TZP and 8Y-TZP by coprecipitation and solid-phase synthesis methods in the steam. Analysis the weight changes of samples using analytical balance, and the sample surface microstructure and phase changes with SEM, XRD. The results show that the content of Y2O3 and synthesis method all affect the aging properties of zirconia ceramics; solid-phase synthesis of 8Y-TZP has the best anti-aging performance.
Authors: Chang Tian Huan, Dan Yu Jiang, Ge Ming Liu, Qiang Li
Abstract: There are many bonding methods of the ceramic sintered body, such as diffusion bonding, glass bonding, and reports in this regard are not difficult to see. But the solid electrolyte zirconia ceramic bonding in NOx sensor is rarely reported. Here we use zirconia and aluminum-silicon glass together to bond zirconia ceramic sintered body, and tested the electrochemical performance with AC (alternating current) impedance spectroscopy, EMF (electromotive force) of the adhesive layer. The results indicates that the the electrochemical performance is good.
Authors: Cheng Zhang, Na Zhang, Dan Yu Jiang, Ling Cong Fan
Abstract: The high sintering temperatures required for solid-state derived powders is a significant obstacle inhibiting more widespread use of single pure phase BaZrO3 with high density. The aim of this research was to reduce the sintering temperature whilst maintaining pure single phase BaZrO3. By using of sintering aid, such as TiO2 additive, the pure perovskite BaZrO3 powder have been fabricated with the solid state chemistry at 1250°C. Low levels of TiO2 (3%) produced the pure BaZrO3 particles with the smallest size, and the corresponding sintered ceramic has the density of 95% theoretical using sintering temperature as low as 1550°C. The microstructure of the particular ceramic with full density confirmed that the particle grain in ceramic block have shaped with the less pore and connected thickly.
Authors: Yi Kun Liao, Dan Yu Jiang, Ya Ming Ji, Jian Lin Shi
Abstract: Y2Hf2O7 and Lu2Hf2O7 precursor powders are prepared by nitrate solution combustion method with various fuels at 450°C, respectively. Phase evolution of the synthesized powders was determined by X-ray diffraction (XRD) techniques. Single-phase cubic Y2Hf2O7 and Lu2Hf2O7 crystalline powders were obtained by calcining the resultant combustion ash at 800°C for 2h. By controlling the pH of the nitrate solution, the type of fuel and the ratio of fuel/nitrate, nanosized powders can be obtained. The crystallite size of resultant powders is much related to the combustion flame temperature, which can be controlled by controlling the type of fuel and adjusting the fuel-to-oxidizer ratio. The influence of the ratio of reactants and the type of fuel on the properties of the final products was investigated. The crystal size and morphology were analyzed by TEM.
Authors: Ping Ping Wu, Cheng Zhang, Hai Fang Xu, De Xin Huang, Bing Xu, Dan Yu Jiang
Abstract: Static short-term corrosion tests were performed to two kinds of borosilicate glasses in deionized water, at 70°C and 150°C, respectively. Same corrosion experiments were also carried out in other leaching agents, such as simulated under ground water of Beishan, sulfuric acid solution (pH=0.5) and potassium hydroxide solution (pH = 13). Experimental results show that both leaching agent and corrosion temperature co-dominate the corrosion process, and the temperature plays more important role. At low temperature of 70°C, the corrosion reaction is controlled by the ion diffusing in DIW at earlier stage. While in PHS, network hydrolysis reaction is the main corrosion mechanism.
Authors: Yin Juan Chen, Jie Song, Qiang Li, Dan Yu Jiang
Abstract: This work mainly studied the corrosion and dissolution performance of fused magnesia in alkaline solution . The influences of temperature, time and the concentration of alkaline solution on the weight change and particle morphology of magnesia powder were investigated. The corrosion mechanism and dynamics of the magnesia in alkaline solution were discussed by measuring the weight change and XRD analysis. Above results of dissolution studied of fused magnesia powders in alkaline solution would offer important corrosion information for ceramic bulks.
Authors: Hong Qin Wang, Ge Ming Liu, Niu Sheng Peng, Tao Feng, Jin Feng Xia, Dan Yu Jiang, Xiu Chun Yang
Abstract: With the growing problem of automobile exhaust pollution, the study of automotive oxygen sensor is very meaningful, nitrogen oxides accounts for a large proportion of automobile exhaust. AC impedance spectroscopy of the NOx sensor in different temperature(500°C,600°C,700°C) and NO2 of different concentrations (100ppm,500ppm,1000ppm)in this paper, the influence of temperature and gas concentration on NOx sensors is explored.
Authors: Tao Feng, Dan Yu Jiang, Jian Lin Shi
Abstract: Cr-doped Y3ScxAl(5-x)O12(Nd:YSAG) powder have been prepared with a combustion method. The powders are nanosized and a pure cubic phase when calcined at 900°C. Transparent Cr:YSAG ceramics were successfully fabricated by sintering the powder compact at 1800°C under H2 atmosphere. The optical properties were investigated in detail. It was found that after Sc substitute for Al, the The octahedral crystal-field parameter Dq and Dq/B was reduced, and that is why the absorption peak move to the longer wavelength side but the emission peak not moved.
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