TY - CONF A1 - Naghib Zadeh, Hamid T1 - LTCC-integrierbare Kondensatorwerkstoffe auf Basis von Bariumtitanat T2 - Sitzung des Arbeitskreises "Funktionskeramik" CY - Jena, Germany DA - 2012-10-17 PY - 2012 AN - OPUS4-26703 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Naghib Zadeh, Hamid T1 - Characterization of NiCuZn ferrite layer co-fired with LTCC dielectric tapes T2 - 13th International Conference of the European Ceramic Society CY - Limoges, France DA - 2013-06-23 PY - 2013 AN - OPUS4-28839 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Naghib Zadeh, Hamid A1 - Rabe, Torsten A1 - Karmazin, R. T1 - Integration of MnZn-ferrite tapes in LTCC multilayer N2 - For co-firing of MnZn-ferrite tapes and LTCC dielectric tapes, the sintering shrinkage curves and the coefficient of thermal expansion of ferrite and dielectric tapes were matched. Highly densified embedded ferrite without any cracks could be manufactured by co-firing at 900 °C in nitrogen atmosphere. However, the permeability of MnZn-ferrite co-fired between dielectric tapes is significantly reduced (µ´=100) compared to that of the separately sintered ferrite (µ´=500). Changes in the phase stability and microstructure of MnZn-ferrite were investigated to explain the permeability reduction in the embedded ferrite. It is supposed that early densification of the dielectric tapes on the top and bottom of the ferrite layer prevent the gas exchange during sintering which is necessary for (Mn,Zn)Fe2O4 spinel formation. As a result, high amount of Fe2O3 secondary phase and a Mn-rich spinel phase with low permeability remain in the embedded ferrite layer. KW - LTCC KW - MnZn-ferrite KW - Co-firing PY - 2013 DO - https://doi.org/10.1007/s10832-013-9800-5 SN - 1385-3449 SN - 1573-8663 VL - 31 IS - 1-2 SP - 88 EP - 95 PB - Kluwer Acad. Publ. CY - Boston, Mass. [u.a.], USA AN - OPUS4-29385 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Naghib Zadeh, Hamid T1 - Anwendung der Master-Sinter-Kurve bei der Co-Sinterung von Werkstoffkombinationen T2 - Jahrestagung der Deutschen Keramischen Gesellschaft 2012 CY - Nuremberg, Germany DA - 2012-03-05 PY - 2012 N1 - Geburtsname von Mieller, Björn: Brandt, B. - Birth name of Mieller, Björn: Brandt, B. AN - OPUS4-25517 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rabe, Torsten A1 - Naghib Zadeh, Hamid A1 - Glitzky, Carsten A1 - Töpfer, J. T1 - Integration of Ni-Cu-Zn ferrite in low temperature Co-fired ceramics (LTCC) modules N2 - Integration of magnetic functional components in LTCC circuit boards calls for co-firing of dielectric and ferrite tapes. Ni-Cu-Zn ferrites with permeability of µ = 900 were fully densified at the standard LTCC sintering temperature of 900°C. Co-firing of this ferrite with dielectric tapes requires the adaptation of the shrinkage behavior of the materials as well as the thermal contraction during the cooling period – especially in the temperature range below the transformation point of the glass phase of the dielectric tape. To match these preconditions, a new dielectric LTCC material with steep sintering curve and high thermal expansion coefficient was designed. Sintered multilayer laminates composed of Ni-Cu-Zn ferrite and tailored dielectric tapes are free of cracks and possess no open porosity. No significant interdiffusion between the ferrite and dielectric tapes was found using microprobe analysis. Pure ferrite laminates show homogeneous microstructure with large grains up to 50 µm in diameter. However, growth of ferrite grains does not take place near the interface between ferrite and release or dielectric tapes. There is a strong correlation between permeability and volume fraction of large ferrite grains. Compared to pure ferrite laminates the permeability of co-sintered Ni-Cu-Zn ferrite layers is drastically reduced to 400, that is a decrease of more than 50%. PY - 2012 DO - https://doi.org/10.1111/j.1744-7402.2011.00712.x SN - 1546-542X SN - 1744-7402 VL - 9 IS - 1 SP - 18 EP - 28 PB - American Ceramic Soc. CY - Westerville, Ohio AN - OPUS4-25544 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mieller, Björn A1 - Naghib Zadeh, Hamid A1 - Rabe, Torsten T1 - Improved co-firing of ferrite and dielectric tape based on master sintering curve predictions and shrinkage mismatch calculations N2 - Co-firing of low temperature co-fired ceramics (LTCC) and functional ceramics like ferrites is a promising approach to increase the level of integration in future microsystems, and to create new applications for LTCC technology. Besides the development of compatible material combinations, the configuration of the sintering process is an important issue for successful co-firing. A method is presented to derive the linear shrinkage mismatch of a material combination based on density data calculated from the master sintering curves (MSCs) of the individual materials. The influence of the firing profile on the constraint in the combined multilayer can be anticipated using this method. To investigate and improve the co-firing of ferrite and dielectric tape, the shrinkage mismatch with respect to heating rate was studied. A significant reduction of shrinkage mismatch was found for increased heating rates. The calculated results are verified by lateral shrinkage measurements on combined laminates. PY - 2013 DO - https://doi.org/10.1111/jace.12179 SN - 0002-7820 SN - 1551-2916 N1 - Geburtsname von Mieller, Björn: Brandt, B. - Birth name of Mieller, Björn: Brandt, B. VL - 96 IS - 3 SP - 726 EP - 730 PB - Blackwell Publishing CY - Malden AN - OPUS4-27955 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Naghib Zadeh, Hamid A1 - Rabe, Torsten T1 - Pressure-assisted sintering of multilayer transformer using LTCC-compatible NiCuZn-ferrite and silver conductor N2 - A low-fired NiCuZn-ferrite and a new LTCC dielectric material with matched sintering shrinkages and coefficients of thermal expansion were used for integration of magnetic function into LTCC. Silver was used as inner conductor material. Silver diffusion during sintering into the surrounding glassy phase modifies the sintering behaviour of LTCC near the silver conductor and generates warping and delamination of the multilayer. Silver diffusion can be prevented by sintering in nitrogen atmosphere. However, sintering in nitrogen atmosphere causes partial decomposition of NiCuZn-ferrite by reduction of divalent copper oxide (CuO) to cuprite (Cu2O). It was found that diffusion of silver and associated deformation can be highly reduced if a higher heating rate during sintering in air is used. A Defect-free multilayer transformer with several silver conductive layers could be manufactured by pressure-assisted sintering only. T2 - CICMT 2012 - 8th International conference on ceramic interconnect & ceramic microsystems technologies CY - Erfurt, Germany DA - 16.04.2012 KW - LTCC KW - Ferrite KW - Silver conductor PY - 2012 IS - Session WP 1 / WP 15 SP - 000476 EP - 000483 AN - OPUS4-27775 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -