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Green Sheets (green + sheet)
Selected AbstractsAqueous Processing of Titanium Carbide Green SheetsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2001Jing-Xian Zhang TiC sheets were prepared by an aqueous tape-casting process. The zeta potential measurement showed that the isoelectric point for TiC powders in the absence of dispersant had a pH value of ,3.3. According to the surface properties of TiC powders, a cationic polymer PEI was selected as dispersant. In the presence of dispersant, the isoelectric point increased to a pH value of ,10.4. The slip stability was determined by visual observation of the fluidity of the slip as well as the settling of the powders. Results showed that the amount of dispersant required to achieve a minimum of viscosity for 50 vol% suspensions was equal to 1.2 wt%. In the absence and presence of dispersant, stable slips could be obtained in the pH ranges 7,9 and 11,12, respectively. The rheological measurements showed that with PEI as dispersant, TiC suspensions exhibited a small time dependent behavior. With polyvinyl alcohol as binder and glycerol as plasticizer, suspensions showed a thixotropic feature. As-cast tapes were dried in air at room temperature. The results showed that it was possible to fabricate homogeneous green tapes with smooth surfaces from these suspensions. [source] Development, Analysis, and Application of a Glass,Alumina-Based Self-Constrained Sintering Low-Temperature Cofired CeramicINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 5 2007Takahiro Takada The effects of an inner constraint layer and alumina particles on the microstructure, strength, and shrinkage of the laminated low-temperature cofired ceramic (LTCC) green sheet were investigated. Alumina particles of several sizes were used in the inner-constraint layer in order to strengthen the LTCC substrate. Smaller alumina particles in the inner-constraint layer produced a substrate with a high bending strength. Sintering shrinkage in the x,y direction of the LTCC is related to the bending strength of the debinded alumina particle layer used for an inner-constraint layer. A larger pore size in the inner-constraint layer was found to increase the distance of the glass penetration from the glass,alumina layer into the inner-constraint layer. The total thickness of the constraint layer changes the shrinkage in the x,y direction and the bending strength. [source] Comparison of Water-Based and Solvent-Based Tape Casting for Preparing Multilayer ZnO VaristorsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2008Lanyi Wang Water-soluble acrylic was used as the binder of the water-based (aqueous) slurry while polyvinyl butyral was the binder of the solvent-based (nonaqueous) slurry. Both types of slurry exhibited shear thinning properties suitable for tape casting. The casting parameters for them were different when the same thick green sheets were cast. Thermogravimetric analysis was used to find the binder burnout temperatures of the aqueous and nonaqueous green tape. Scanning electron microscopy (SEM) studies revealed that both types of green tapes have smooth defect-free surfaces but the aqueous green tape is denser than the nonaqueous one. The multilayer ZnO varistors prepared by aqueous tape casting display comparable good electrical properties to those prepared by nonaqueous tape casting because both types of ceramic have a uniform, fine grain microstructure with a homogeneous dopant distribution indicated using SEM and transmission electron microscopy. [source] Fabrication of Gradient Pore TiO2 Sheets by a Novel Freeze,Tape-Casting ProcessJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2007Linlin Ren Gradient pore structure TiO2 sheets were fabricated by a novel freeze,tape-casting process. Aqueous TiO2 ceramic slurries were prepared by the traditional tape-casting processing and were then cast onto an aluminum foil carrier. The slurries were immediately frozen on the substrate, whose temperature was about ,18°C. After freezing completely, the green sheets were then dried in a lyophilizer. Freeze,tape casting led to formation of a gradient pore microstructure of the TiO2 sheet. The results showed that the solid loading of slurry considerably affected the pore microstructure, pore morphology, and the porosity. Solid loadings of 10, 20, 30, 40, and 50 wt% slurries were used, respectively, and the gradient pore structure TiO2 sheets with different porosities of 75%,88% were obtained. [source] | ||||||||||