Papers by Keyword: Tape Casting

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Authors: Andreas Roosen
Abstract: Miniaturisation and multi-functionality are the driving forces in the field of many technical market segments. Ceramic multilayer technology via tape casting and lamination is one of the key technologies to generate complex, highly integrated devices for future applications. The technique offers a tremendous potential for the integration of different materials combined with the possibility to form complex 3-D structures by layered object manufacturing. The ceramic multilayer technology is based on shaping, screen-printing and stacking of individual ceramic green tapes, which are laminated and co-fired. The tapes can offer ferroelectric, piezoelectric and magnetic behaviour, insulating and semi-conducting properties, voltage-, temperature- and atmosphere-dependent resistances, high thermal conductivity, corrosion resistance, or bio inert behaviour. For the integration of additional features like reactors or sensors, the described layered manufacturing method allows to introduce simultaneously microchannels and other cavities. - New developments in processing and in materials concepts are addressed to overcome limitations and to take maximum advantage of this technique. The technique is illustrated considering e.g. microwave circulators for communication, sensors for automotive applications, and piezoelectric actuators as examples, which demonstrate the potential of the technology for the manufacture of highly integrated multifunctional systems.
Authors: Agata Strojny-Nedza, Katarzyna Pietrzak, Marcin Chmielewski, Katarzyna Jach
Abstract: It has been known for many years that the incorporation of metallic particulates into a ceramic matrix can bring about the improvement of the mechanical properties of ceramics. Alumina/copper composites are well-known for their good frictional wear resistance, high resistance to thermal fatigue, high thermal conductivity as well as high absorption and dissipation of heat. The combination of the properties offered by alumina-copper composites makes them particularly interesting for wear applications in both automobile and aerospace industries. In the present paper we report on the design and production of a new class of alumina-copper functionally graded materials (FGM) which have technological potential for application in automotive brake disks. More specifically, this work deals with the development of the interpenetrating network structure of the FGM material. The manufacturing procedure was based on the gas-pressure infiltration of graded porous alumina preforms by liquid copper. The graded porous ceramic preforms with porosity ranging between 20 and 60% were made by casting foils made from slurries, the main components of which were alumina powder and rice starch powder (a pore forming agent), laminating these foils, subsequently burning-out the starch and last but not least performing a sintering process. A fundamental part of the presented investigations was to correlate the grain size of the alumina powders (Almatis, HVA FG and CT 1200 SG) and the pore size distribution, microstructure and selected mechanical and thermal properties of the porous ceramic preforms.
Authors: Se Young Choi, Il Seok Park, Deuk Yong Lee, Jung Suk Han, Dae Joon Kim
Abstract: Aqueous alumina tapes were prepared by a doctor blade using polyvinyl pyrrolidone (PVP) as a binder and gelatin and polyvinyl alcohol (PVA) as additional binders to improve drying rate and mechanical properties of the tapes containing PVP. As binder was prepared by mixing 89.5 wt% of PVP, 10 wt% of PVA, and 0.5 wt% of gelatin, tape properties were optimized showing complete drying in 3h, tensile strength of 1 MPa, and high flexibility. Marginal gap of all-ceramic dental crowns prepared using the tapes was about 56 µm indicating the tape cast alumina dental crowns are clinically applicable.
Authors: Isabel Santacruz, Carlos A. Gutiérrez, María Isabel Nieto, Rodrigo Moreno
Authors: Sen Mei, Juan Yang, José Maria F. Ferreira, Rodrigo Martins
Authors: M.F.L. Granja, F. Doreau, José Maria F. Ferreira
Authors: Dae Joon Kim, Il Seok Park, Hyeon-Ju Choi, Doug Youn Lee, Jung Suk Han
Authors: Shu Long Liu, Qiang Shen, Guo Qiang Luo, Mei Juan Li, Lian Meng Zhang
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 Pnd 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.
Authors: Xi Geng Miao, Xian Gao Zhang, Xiao Wei Fang, Fabrizia Ghezzo, Zhi Ya Zhao, Ruo Peng Liu
Abstract: A glass powder of the SiO2-Al2O3-K2O-Na2O system was added to fused silica particles to form composite green compacts by tape casting. This procedure was able to lower the sintering temperature of the fused silica particles making the composites suitable for being co-fired with the silver-palladium (Ag-Pd) paste commonly used as a conductive circuit in several microwave applications. The resulting new ceramic composite with the composition of 50 wt% fused silica and 50 wt% glass (brand name: TC-3) had a low dielectric constant and a low loss tangent of 2.7 and 2.5-3.7 x10-3 , respectively, and was able to be co-fired with the Ag-Pd conductive paste at the temperature of 895 °C, resulting in a potential low temperature co-fired ceramic (LTCC) system for microwave applications.
Authors: Antonio Javier Sanchez-Herencia, Carlos A. Gutiérrez, A.J. Millán, María Isabel Nieto, Rodrigo Moreno
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