TY - CONF A1 - Heuser, Lina A1 - Sobek, P. A1 - Müller, Ralf A1 - Körner, S. T1 - Sintering of silver-glass composites N2 - High conductive silver metallization pastes are key components in advanced electronics and photovoltaics. Increasing demands on efficiency, miniaturization and ever shorter time-to-market require tailored glass-silver-pastes. In these pastes, low-melting glasses act as a sintering aid achieving better sintering, adhesion and contact formation for solar cells. Yet, the related liquid phase sintering of silver-glass-composites and the underlying mechanism of silver dissolution, transport and reprecipitation are rarely investigated. In this study, systematically varied low melting alkaline zinc borate, alkaline earth borate, and Pb- and Bi-glasses are investigated. Glass transition and crystallization are studied with dilatometry, DTA and XRD. Sintering of the pure glasses, pure silver and silver-glass-composites is analyzed with Hot Stage Microscopy, optical and electron microscopy. Since oxygen dissolved in silver powders can affect the silver dissolution as silver oxide in the matrix oxide glasses, the O2-content of silver powders is determined by Vacuum Hot Extraction. The glass transition temperature of the glasses under study varies between 370 °C and 590 °C whereas the sinter onset largely ranges between 400 °C and 600 °C. On the other hand, it scattered between 200 °C and 450 °C for selected commercial Ag-powders of different particle size and morphology. T2 - 93rd Annual Meeting of DGG in Conjunction with the Annual Meeting of  USTV CY - Nuremberg, Germany DA - 13.05.2019 KW - Silver glass paste KW - Sintering KW - Microstructure PY - 2019 AN - OPUS4-48906 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Blaeß, Carsten A1 - Müller, Ralf A1 - Feldmann, Ines A1 - Brauer, D.S. T1 - Sintering ability of fluoride-containing bioactive glass powder N2 - Sintered bioactive glass scaffolds of defined shape and porosity, e.g. made via additive manufacturing, must provide sufficient bioactivity and sinterability. As higher bioactivity is often linked to high corrosion and crystallization tendency, a certain compromise between sintering ability and bioactivity is therefore required. Groh et al. developed a fluoride-containing bioactive glass (F3), which allows fiber drawing and shows a bioactivity well comparable to that of Bioglass®45S5. To study whether and to what extent the sinterability of F3 glass powder is controlled by particle size, coarse and fine F3 glass powders (300-310µm and 0-32µm) were prepared by crushing, sieving and milling. Sintering, degassing and phase transformation during heating were studied with heating microscopy, vacuum hot extraction (VHE), DTA, XRD, and SEM. For the coarse glass powder, sintering proceeds slowly and is limited by surface crystallization of primary Na2CaSi2O6 crystals. Although the crystallization onset of Na2CaSi2O6 is shifted to lower temperature, full densification is attained for the fine powder. This finding indicate that certain porosity might be tuned via particle size variation. Above 900°C, intensive foaming is evident for the fine powder. VHE studies revealed that carbon species are the main foaming source. T2 - 92. Glastechnische Tagung CY - Bayreuth, Germany DA - 28.05.2018 KW - Sintering KW - Bioactive glass KW - Crystallization PY - 2018 AN - OPUS4-45568 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -