Papers by Keyword: Gelcasting

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Authors: Hao Huang, Da Ming Cheng, Jian Feng Tong, Bao Wei Li, Ling Wang
Abstract: A technique for the preparation of porous ceramic materials by gelcasting mothod is studied using a water-soluble epoxy resin combined with a amine hardener. The increase in the volume and rheological behavior of slurry , TGA and DSC of the green bodies are investigated. The influence of solid content on the relative density, the cell size distribution and the compressive strenghth is studied. The experimental results show that in the measurable shear rate range the rheology of slurry exhibt a shear thinning behavior, the relative density increase with the solid content, with the decrease of the relative densities the cell size increase. The compressive strength increased exponentially with the increase relative density, and the exponent, m, is 1.094.
Authors: Yue Min Wang, Jun Liu, Chao Wang, Ling Juan Fei, Ya Wei Han, Jian Jun Wang
Abstract: The gelcasting technique was used to fabricate 95 alumina ceramics green bodies. The gel system based on MAM-MBAM was low-toxicity in this study. The green bodies and the sinter obtained with solid content of 55vol% had high strength, density and quality. The influences of the monomers mole ratio (MAM/MBAM) and the monomers content (MAM and MBAM) on the compressive strength of green bodies, the solid content on the density, compressive strength and the shrinkage rate of green bodies were also discussed. The experimental results showed that the best mole ratio of MAM/MBAM was 12/1. Compressive strength increased with the increase of monomers content (MAM and MBAM). The microstructure of the green bodies indicated that the ceramic powders were connected by polymeric networks, and the ceramic powders in the green body distributed homogeneously and compactly.
Authors: Kai Cai, Yong Huang, Jin Long Yang
Authors: Jun Ping Wang, Jing Wang, Xiao Bing Zhou, Lei Jing, Penchal Reddy Matli, Qing Huang
Abstract: Zirconium diboride (ZrB2) ceramics were synthesized by Aqueous gelcasting method sintering effects of the additives were examined. The dispersion and rheological properties behavior of water-based gelcasting ZrB2-4wt.%B4C suspensions were characterized by zeta potential and viscosity measurements, respectively. A 50 vol.% ZrB2-4wt.%B4C suspension with a relative low viscosity was prepared with 3wt.% A70 and 4wt.% AM at pH = 11. Using the liquid desiccant drying method, the weight loss was 7.7 % after drying for 24 h, which is higher than the drying at RT (7.2 %).
Authors: Isabel Santacruz, Carlos A. Gutiérrez, María Isabel Nieto, Rodrigo Moreno
Authors: Jyoti Prakash Nayak, Japes Bera
Abstract: Silica-based porous bioactive ceramics was prepared by gel-casting method using silica xerogel powder. Xerogel was derived from rice husk ash. 42 vol.% solid containing slurry was prepared in 1:30 (MBAM:AM) monomer cross-linker solution. The srurry was thixotropic. Gel-casted body was machined efficiently. Dired cast body was sintered at 1100oC. Apatite layer was formed on silica body during In vitro bioactivity experiment. The results suggest that the gel-casted silica ceramics can be used as a bioceramics.
Authors: Frans M.M. Snijkers, Steven Mullens, Anita Buekenhoudt, Jan Luyten, W. Vandermeulen
Abstract: Ceramic foams can be used as filters, dust collectors, light weight components and catalyst carriers. They can be produced by a variety of techniques. The performance of ceramic foams will be strongly improved when their mechanical properties are improved. For this reason, we produced ceramic foams both by a modified reaction bonded (RB) replica technique and by gel casting. With both methods, reticulated foam structures with enhanced mechanical strength were obtained. Zeolites are a special type of materials that are characterized by high catalytic properties. They can be brought on a structured carrier by dip and slurry coating. Nevertheless, in situ coating has as main advantage that the support is used as the base for nucleation. This results in the formation of a chemical bond between the zeolite crystals and the support. The goal of this contribution is twofold: at first we demonstrate how Al2O3 foams with improved mechanical strength can be produced both by the modified RB-alumina replica technique and by gel casting. Secondly, it is shown that these ceramic foams can be coated with (silicalite) zeolite crystals by insitu crystallization from a precursor sol. The two-layer material combinations have been characterized with FESEM, XRD, CT (computer assisted tomography), IA (Image Analysis) and by mechanical tests.
Authors: Claudinei dos Santos, Pedro H.B. Prado, Fernando dos Santos Ortega
Abstract: Gelcasting is a novel method of forming ceramics and has been increasingly employed in preparing complex-shaped, near-net-shape advanced materials. In this work, alumina, zirconia and alumina-zirconia bioceramics were shaped by gelcasting, using MAM-MBAM monomer system, with subsequent sintering and characterization. High purity tetragonal ZrO2 (3mol%Y2O3) and .Al2O3 powders were used as starting powders. Powder mixture containing 80 wt.% of alumina and 20 wt.% of tetragonal zirconia were obtained by milling/homogenization. In all cases, the suspension obtained had at least 55 vol.% solid loading. Ceramic bodies were demolded, dried and characterized by green relative density. The compacts were sintered in air at 1550 and 15750C, for 120 minutes, with controlled heating-rate to facilitate organic compounds removal. Sintered samples were characterized by relative density, and analyzed by X-Ray diffraction and scanning electronic microscopy. Hardness and fracture toughness were determined using Vicker’s indentation method.
Authors: Antonio Javier Sanchez-Herencia, Carlos A. Gutiérrez, A.J. Millán, María Isabel Nieto, Rodrigo Moreno
Authors: Jin Long Yang, Liang Su, Li Guo Ma, Yong Huang
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