Papers by Author: Lian Meng Zhang

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Authors: Dong Ming Zhang, You Jun Li, Lian Meng Zhang, Jing Kun Guo
Abstract: Aluminum borate whiskers with TiB2 as borate source were prepared in this paper. The phase transformation process was analyzed by XRD and TG-DSC. The results indicate that TiB2 was decomposed into TiO2 and B2O3 in the calcining process in the active [O] atmosphere. 2Al2O3.B2O3 was formed in the lower temperature with reaction of Al2O3 and B2O3, while 9Al2O3.2B2O3 whiskers were grown by compensation of 2Al2O3.B2O3 at higher temperature (above 1050oC)
Authors: Lian Meng Zhang, Qiang Shen, Zhong Min Yang
Abstract: In the present paper, a kind of Mo-Ti system functionally graded material with a continuous change of composition was formed via particle settling method at first, and then it was desified by hot-press under 1473K-30MPa-1h. Finally, by using an axisymmetric finite element method, the fabricated thermal stresses in a disk-shaped Mo-Ti FGM were calculated. The results showed that the thermal stresses changed continuously with the smooth variation of graded composition. The residual tensile stresses in the Mo-Ti FGM with a continuously changed composition were located in the medial region of graded layer and the radial compressive stresses distributed in the Mo- and Ti-rich sides. The calculated maximum residual tensile stresses in the Mo-Ti FGM were much lower than the bending strength of Mo-Ti alloys, which demonstrated that during fabrication no damages occurred in the Mo-Ti FGM with continuously graded composition.
Authors: Chuan Bin Wang, Qiang Shen, Guoqiang Luo, Lian Meng Zhang
Abstract: In the present paper, the relationship between characteristic wave impedance and compositions was mainly investigated in order to find a suitable theoretical model for predicting the impedance value of Ti-Mo system composites and FGM. At first, dense Ti-Mo composites with different weight fractions of Mo were prepared. Then the transverse and longitudinal wave velocities of the samples were measured and the characteristic wave impedance values were obtained. A mixture model was adopted to estimate the characteristic wave impedance value of Ti-Mo composites. Comparisons between the estimated and experimental results demonstrated that the suggested model was sufficiently accurate to predict the characteristic wave impedance value of Ti-Mo system composites and FGM.
Authors: Jin Feng Dou, Qiang Shen, Lian Meng Zhang
Authors: Yun Long Yue, Y.S. Gong, Qiang Shen, Lian Meng Zhang
Authors: Chang Lian Chen, Qiang Shen, Jun Guo Li, Lian Meng Zhang
Abstract: A series of zirconia porous ceramics with different density are fabricated with commercial zirconia powder and zirconia hollow balls by pressureless sintering technology. The microstructure and phase transformation are characterized respectively by SEM and XRD testing methods. The result indicates that the density and compressive strength depend greatly on zirconia powder content at the same sintering temperature, and elevating sintering temperature just has a little effect on the density and compressive strength for the samples of the same zirconia powder content. The XRD diffraction patterns analysis shows that elevating sintering temperature is helpful to eliminate monoclinic zirconia and the best sintering temperature should be beyond 1700°C.
Authors: Min Xian Shi, Zhi Xiong Huang, Tao Wei, Lian Meng Zhang
Abstract: 0-3 piezoelectric ceramic PMN/conductive carbon black(CB)/epoxy resin(EP) composites were prepared by resin casting method. The electric and damping properties of PMN/CB/EP composites were detected. The volume resistivity of the composites decreases with the addition of conductive carbon black, and the composites experience transition from insulator to semiconductor when the CB content is 6% weight of the resin in the composites. Damping loss factor-temperature curves scanned by DMA showed that the peak value of damping loss factor(tanmax), the loss factor area(TA) and the damping temperature range(T) of the composites increase and reach to maximum values when CB content is 6% weight of EP resin, then drop a little with CB contents further increasing. When CB was just at threshold content 6% of epoxy weight the composite converts from insulator to semiconductor with the volume resistivity being about 108 Ωm and piezo-damping mechanism plays efficiently.
Authors: Qiang Shen, Z.D. Wei, Mei Juan Li, Lian Meng Zhang
Abstract: AlN ceramics doped with yttrium oxide (Y2O3) as the sintering additive were prepared via the spark plasma sintering (SPS) technique. The sintering behaviors and densification mechanism were mainly investigated. The results showed that Y2O3 addition could promote the AlN densification. Y2O3-doped AlN samples could be densified at low temperatures of 1600-1700oC in 20-25 minutes. The AlN samples were characterized with homogeneous microstructure. The Y-Al-O compounds were created on the grain boundaries due to the reactions between Y2O3 and Al2O3 on AlN particle surface. With increasing the sintering temperature, AlN grains grew up, and the location of grain boundaries as well as the phase compositions changed. The Y/Al ratio in the aluminates increased, from Y3Al5O12 to YAlO3 and to Y4Al2O9. High-density, the growth of AlN grains and the homogenous dispersion of boundary phase were helpful to improve the thermal conductivity of AlN ceramics. The thermal conductivity of 122Wm-1K-1 for the 4.0 mass%Y2O3-doped AlN sample was reached.
Authors: Guo Qiang Luo, J. Li, Dong Ming Zhang, Qiang Shen, Lian Meng Zhang
Abstract: Dense SnO2 based ceramics are widely used. In this paper, 95SnO2-5MnO2 ceramics were prepared by pressureless sintering in air at different temperatures. Phase compositions and microstructures are examined by XRD, SEM and EDX, respectively. The SEM results show that different morphologies exist at the SnO2 grain boundary of ceramic, which compose of manganese oxidation, testified by EDX. The different manganese oxides phases, found by XRD, are the source of oxygen concentration at the grain boundary during heating and oxygen dissipation when cooling. However, solid solutions of Mn, Sn and O are not observed. The density of 95SnO2-5MnO2 ceramics decreases with increasing the sintering temperature, due to the evaporation of SnO and decreasing concentration of oxygen at grain boundary in the cooling process. Densification of the ceramic is promoted with inhibiting the decomposition of SnO2 by increasing oxygen concentration in the heating process, but it is limited by the dissipation of oxygen at the grain boundary in the cooling process.
Authors: Xue Ping Li, Fei Chen, Qiang Shen, An Xue Wang, Lian Meng Zhang
Abstract: High Density Antimony-Doped Tin Oxide (ATO) Ceramic Targets Are the Crucial Materials for Preparation of High Quality Transparent Conductive ATO Thin Films in Sputtering Process. In the Present Work, ATO Nanopowders with Different Sb2O3 Doping Content (0~10 mol%) Were Used to Fabricate the ATO Nanoceramics by Spark Plasma Sintering (SPS) Technique, which Can Reduce the Densification Temperature and Restrain a Grain Growth. And the Effect of Sb2O3 Doping Content (0~10 mol%) on the Density and Microstructure Had Been Investigated. the Results Showed that with the Sb2o3 Doping Content Increase, the Relative Density of ATO Nanoceramics Is Increased and the Resistivity Is Decreased. When the Sb2O3 Doping Content Is 10 mol%, the Relative Density Is 97.2% and the Resistivity Is 7.9×10-2 Ω•cm.
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