Papers by Author: Chang An Wang

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Authors: Xue Min Cui, Yong Huang, Ji Zhou, Chang An Wang, Shi Xi Ouyang
Abstract: As a good binder for aqueous Al2O3 suspensions tape-casting process, a commercial styrene-acrylic latex binder had been investigated. This paper studied on the rheological behaviors of the suspensions and drying process of aqueous slurries with latex binder system, and the research results indicated the rheological behaviors was affected by pH value, solid loading and dispersant (PAA-NH4) additives; and the drying speed of slurries was most decided by drying temperature and slurry coating thickness.
Authors: Ke Tang, Chang An Wang, Ai Guo Zhou, Li Feng Wu, X.L. Xu, Yong Huang
Authors: Hai Long Wang, Shi Xun Zhang, De Liang Chen, Qian Fei Han, Hong Xia Lu, Hong Liang Xu, Chang An Wang, Rui Zhang
Abstract: ZrB2 powder has been prepared through carbothermal reduction boronization of zirconia/boron carbide/carbon mixtures heating assisted by microwave. The powder characteristics were investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF), nitrogen absorption (BET model) and scanning electron microscope (SEM). The experiments indicated that excessive B4C is necessary and the carbothermic reaction reacts severely at a higher temperature and complete at 1600oC. The crystallite size has ranged from 50-100 nm, according to the calculated surface area. Highest purity of ZrB2 powder, which was synthesized at 1600oC, is 99.67 wt%. The surface area of ZrB2 powder synthesis at 1600oC is 18.33 m2/g. Vibration of temperature should affect the purity of ZrB2, as the sub reaction acted.
Authors: Rui Feng Chen, Yong Huang, Chang An Wang
Abstract: Pores in ceramics have their peculiarity different from common porous materials, so the existing characterization methods should be re-recognized. In the present work, thermal shrinkage curves adequately characterize the dynamic process of porosity evolution in ceramics, and the results are checked by Archimedes method. In order to detect pore-size distribution quantitatively, gas adsorption (BET method), mercury penetration and a new Scanning Acoustic Microscope (SAM) technique are used on Alumina ceramics with large and median pores. The results acquired by these three methods are discussed in detail and unified by the introduction of effective pore-size coefficient t. It shows that a complete characterization system adapt to pores in ceramics should be established.
Authors: Yong Huang, Shi Ke Zhao, Chang An Wang, Rui Feng Chen
Authors: Cui Wei Li, Yong Huang, Chang An Wang, Shu Qin Li, Qing Feng Zan
Authors: Li Zhong Zhou, Chang An Wang, Yong Huang
Abstract: Porous silica ceramics with above 70% porosity were fabricated by gelcasting process using tert-butyl alcohol (TBA) as solvent. Two types of starting powders, α-silica and fused silica, were chosen to fabricate porous silica ceramics. According to XRD analysis, only single α-cristobalite phase can be identified in the sintered samples. SEM observation showed that highly porous skeleton formed by the bonding of molten ceramic particles in porous silica ceramics. Comparing to the samples using α-silica as starting materials, a compressive strength of 6.30MPa was achieved at a porosity of 70.7% when using fused silica as starting materials. A relatively high specific surface area higher than 10m2/g was obtained for both samples, which should be suitable for catalysis applications as catalyst supports.
Authors: Chang An Wang, Ke Tang, Yong Huang
Abstract: Bulk Ti3SiC2 material with 95 wt% of purity was synthesized by hot pressing from Ti, SiC and graphite powders. This work focuses on the electric properties of Ti3SiC2 at high frequency alternating current using a specific clamp device. The result shows that Ti3SiC2 exhibits an electric property of inductance (the order of magnitude is about 10-8 H at 1 ~ 40 MHz), which indicates that Ti3SiC2 shows a stronger electric property of metal rather than that of common ceramics. In this study, the equation to calculate the external inductance of nonferromagnetic metal is also applicable to Ti3SiC2 material at high frequency.
Authors: Yang Song, Chang An Wang, Chun Qing Peng, Yong Huang
Abstract: High-pure bulk Ti3SiC2 samples were fabricated by directly hot-pressing (HP) high-pure Ti3SiC2 powder without any additives at 1200°C to 1500°C for 0.5–2 hours in flow argon atmosphere. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used for phase identification and microstructure evaluation. The fabricated Ti3SiC2 materials have relative high density with high purity, flexural strength of 500-700MPa and fracture toughness of 9-12MPa·m1/2. The influence of sintering temperature and soaking time on the mechanical properties of Ti3SiC2 materials was discussed. The sintering mechanism for Ti3SiC2 powder without any additives was considered to be related with the fragile-ductile transformation of Ti3SiC2 at 1100°C.
Authors: Ying Lang, Chang An Wang, Jun Zhou
Abstract: Porous mullite ceramics reinforced by mullite fiber have been prepared by vacuum filtering with MgO as sintering aid and starch as pore-forming agent. The influence of different sintering temperature and mullite fiber content on porosity and strength of porous mullite ceramics was investigated. The results showed that the compressive strength of the mullite ceramics increased with increasing sintering temperature. With the increase of mullite fiber content, the compressive strength of porous mullite ceramics appeared to increase at first and then decrease. And the peaking strength could reach 211MPa with 36.8% porosity when 7 vol% mullite fiber was added and sintering temperature of 1500 oC was adopted.
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