Papers by Keyword: Tape Casting

Abstract: Tape casting play a significant role in industrial area, such as multilayered ceramic (MLC) packages, functionally graded materials (FGM), low temperature co-fired ceramics (LTCC) and so on. For the complexity of the rheology for slurry during tape casing process, the control of tape thickness by experience was unstable. Although few numerical and analytical studies on predicting the tape thickness have been done, but these efforts have focused on Newtonian, Bingham, Power law, respectively. There is no unified equation to calculate the tape thickness among different rheological models. In this paper, the calculation results are characterized by wide adaptability; the blade gap, the casting speed and the slurry rheological property are incorporated into calculation; the effect of parameters in the result is studied; Parameter P_nd can be used as a guide to check which mark patterns of the flow velocity profiles in the channel. The results proposed and the experimental measurements from existing publications are in close agreement. Compared with the prediction of the existing models, the calculation results proposed has good agreement with them.

Abstract: Tape casting is widely used in industrial scale for production of multilayer ceramic capacitors or substrates for different applications. In 2009, it was successfully introduced as standard shaping technology for 3 (BSCF) are shown. The entire scope from the preparation of the used powders, the different manufacturing steps and their optimization potential up to the final tape-cast product will be discussed. The influence of the use of pore forming agents, heat treatment or other parameters during processing will be described in detail. Finally, the option of sequential tape casting of different materials for graded structures as a future step in shaping technology will be presented for different applications.

Abstract: La3+ doped textured ceramics CaBi_4-xLa_xTi₄O₁₅ were prepared by oriented consolidation of anisometric particle method with tape casting. The orientation was improved by modifying sintering temperature. The doping of La³⁺ in orientated CaBi_4-xLa_xTi₄O₁₅ ceramics increased the dielectric constant. The higher dielectric constant was obtained in the direction which tropism parallels to the electric field. The relationship between dielectric constant and orientation was discussed.

Abstract: Tape casting method was used to prepare ZnO/TiO2 composite plates for photocatalytic degradation of Reactive Red 180 (RR 180) textile dyes in aqueous solutions. TiO2 content of the plates was selected as 20 mol%. The final sintering temperature of the plates is 700°C. The sintering temperature of 700°C was selected to obtain relatively high surface area of the plates which enhances the photocatalytic activity in the degradation processes. The plates were characterized by using TG-DTA, BET, XRD and SEM. The efficiencies of the composite plates during the degradation of the RR180 dye were determined using the laboratory-scale quartz photoreactor under UVA light irradiation. Over 97% color removal efficiency was obtained in 150min process time for the dye solution at 50 mg/L concentration. Efficient reuse of plates indicated that the successful photocatalytic degradation was maintained after three consecutive runs. The addition of TiO2 is found to increase the photocatalytic activity of the ZnO plates in degradation of the selected dye from water, however, the pure ZnO plates sintered at the same temperature yielded less color removal efficiency for the same dye solution.

Abstract: Residual strain profiles were measured by synchrotron X-ray radiation in Al2O3/Y-stabilized ZrO2 (YSZ) ceramic laminates. Different stacking sequences were employed, including alternating layers containing 5 and 40 vol.% YSZ. Residual strains were found to be fairly constant within each layer; although they change at the interface between layers with different compositions. Different behaviour is observed for the strains along the in-plane and normal directions.

Abstract: The porous NiO/ samaria doped ceria (SDC) cermets, which have been used as the anode-supported for solid oxide fuel cell (SOFC), are fabricated via the tape casting process. In this article using different kinds of slurry system, prepared the large size (60×60mm) anode substrates for SOFC successfully. Effects of solvent, dispersant, plasticizer, binder and the sintering temperature program were investigated. Experimental results show that thicknesses and pore rates of anode substrates are 0.6 ~ 1.5mm and 20% ~ 40% respectively. And all of the complete and flat anode substrates have highly support intensity, for their homogeneous microstructure and pore distribution. Sintering the green pieces of anode substrates at the temperature of 1300°C for 2h, different green pieces have different shrinkages that could be from 20% to 30% measuring with thermal dilatometer. Using this kind of anode substrate, could find out a perfect one to matching the electrolyte film easily.

Abstract: The solid oxide electrolysis cell (SOEC) has been receiving increasing research and attention worldwide due to its potential usage for large-scale production of hydrogen. Tape casting and lamination technique were successfully used to fabricate the NiO-YSZ hydrogen electrode substrate cermets of planar solid oxide electrolysis cell. In this paper the green tape with thickness of 350μm was prepared by tape casting and then the lamination was used to obtain the required thickness for the NiO-YSZ hydrogen electrode-supported electrolyte cermets. The rheological properties of the suspensions with NiO-YSZ and YSZ were studied, respectively. The optimal temperature and pressure of the lamination were determined, and four direction of lamination mode was used according to tape casting direction to obtain symmetrical and even hydrogen electrode-supported electrolyte after co-sintering. Pore-formers were used to increase the porosity of the hydrogen electrode. The green tape was analyzed by TG-DSC analysis, the microstructure was observed by scanning electron microscope. The electrochemical performance of unit cell was measured at 850°C.

Abstract: Tape casting was used for the preparation of Mg-Cu systems density graded materials. A series of tapes with uniform compositions ranging from 100wt% Cu to 100wt% Mg were fabricated with sufficient strength to be handled during the post-processing stage. The effect of the tape casting process parameters on the properties of the tape were studied, such as the composition of the Mg-Cu and the solid loading. The rheology of the slurry of different Mg-Cu composition for tape casting was characterized by viscosity. The tapes characterized by microstructure, thickness and bulk density were outlined. The results demonstrated that the different Mg-Cu composition slurry with well-dispersed, high stability, certain solid loading from 45 ~70 wt% were obtained. The viscosity of the slurry and the density of the green tapes were increased with the increasing of the content of Mg. The thickness of tapes of compositions ranging from 100wt% Cu to 100wt% Mg with certain strength could be achieved 68-110μm and the density of the tapes was 0.74-2.42g/cm3. For 100wt% Cu tapes, when the solid loading was 68wt%, the high density tape was produced. The tapes with different thickness, density and different Mg-Cu compositions were obtained.

Abstract: Anode-supported solid oxide fuel cells (SOFC) are manufactured at Forschungszentrum Jülich by different wet chemical powder processes and subsequent sintering at high temperatures. Recently, the warm pressing of Coat-Mix powders has been replaced by tape casting as the shaping technology for the NiO/8YSZ-containing substrate in order to decrease the demand for raw materials due to lower substrate thickness and in order to increase reproducibility and fabrication capacities (scalable process). Different processing routes for the substrates require the adjustment of process parameters for further coating with functional layers. Therefore, mainly thermal treatment steps have to be adapted to the properties of the new substrate types in order to obtain high-performance cells with minimum curvature (for stack assembly). In this presentation, the influence of selected process parameters during cell manufacturing will be characterized with respect to the resulting physical parameters such as slurry viscosity, green tape thickness, relative density, substrate strength, electrical conductivity, and shrinkage of the different newly developed substrate types. The influencing factors during manufacturing and the resulting characteristics will be presented and possible applications for the various substrates identified.