TY - GEN A1 - Blaeß, Carsten T1 - Crack healing in glass matrix composites N2 - Partially crystalline glasses are predominantly used as solid oxide fuel cell (SOFC) sealants due to their superior long term durability. However, cracks caused by thermal cycling still remain a substantial bottleneck in developing durable SOFC sealants inasmuch as, in contrast to crystal free glasses, large crystal volume fractions can retard healing. Hence, the basic understanding of crack healing in glassy crystalline materials and the effects of micro structure are important for finding optimum micro structures for both, durability and crack healing. For studying these effects, several model glass matrix composites (GMC), for which simultaneous crystal growth and crack healing can be excluded, have been synthesized. Sodium calcium silicate glass – zirconia GMC turned out to provide sufficiently homogeneous, dense and durable model GMC for our studies. The microstructure of this GMC shows large crystal free glassy regions embedded in network of finely dispersed ZrO2 nanoscale crystals. Whereas the glassy regions allow easy local crack healing, the network of dispersed crystals increases the effective viscosity on a global scale. This effect substantially retards crack broadening during later healing stages, which often ends up in large pores. Therefore, this type of microstructure seems to be an interesting candidate for crack healing optimized sealants. T2 - Crystallization 2017 CY - Segovia, Spain DA - 10.09.2017 KW - Glass KW - Glass ceramic KW - Crack healing KW - Microstructure PY - 2017 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/42291 AN - OPUS4-42291 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany