High-Temperature Creep Behavior of SiOC-Based Glasses and Glass-Ceramics

聚合物衍生的玻璃和玻璃-陶瓷（PDC）在过去四十年中是已知的，并且通过合适的聚合物的固态热处理来制备。由于它们的共价键和无定形性质，它们表现出独特的显着性能组合。碳氧化硅（SiOC）三元PDC已被证明具有出色的高温（T > 1000 °C）性能，例如抗结晶和分解、抗氧化和抗腐蚀以及抗蠕变。它们的性质直接受前体的化学性质和分子结构的影响。因此，有一个巨大的潜力，在调整聚合物衍生的陶瓷的微观结构和性能，通过使用定制的聚合物。本提案的目的是系统地研究基于碳氧化硅的PDC的热物理性质和高温蠕变行为，在其依赖于组成和纳米/微观结构方面的背景下。因此，SiOC材料的模型相组成和纳米/微米结构将制备和研究其机械性能在其玻璃化转变温度附近。原子建模方法将补充实验，以证实微观结构特征与特定的机械性能。这种系统的方法将允许深刻理解的SiOC基陶瓷的组合物和网络结构和它们的高温蠕变行为之间的相关性，从而合理地设计聚合物衍生的陶瓷与定制的微观结构和性能。

Polymer-derived glasses and glass-ceramics (PDCs) have been known for the last four decades and are prepared via solid-state thermolysis of suitable polymers. They exhibit a unique combination of remarkable properties due to their covalent bonding and amorphous nature. Silicon oxycarbide (SiOC) ternary PDCs have been shown to possess outstanding high-temperature (T > 1000 °C) properties such as resistance against crystallization and decomposition, oxidation and corrosion as well as against creep. Their properties are directly influenced by the chemistry and the molecular structure of the precursors. Thus, there is an enormous potential in tuning the microstructure and properties of polymer-derived ceramics by using tailored polymers. The aim of the present proposal is to systematically investigate the thermophysical properties and high temperature creep behavior of silicon oxycarbide-based PDCs within the context of their dependence on compositional and nano/microstructural aspects. Thus, SiOC materials with model phase compositions and nano/microstructures will be prepared and studied with respect to their mechanical properties at temperatures near to their glass transition. Atomistic modeling approaches will complement the experiments in order to corroborate microstructural features with specific mechanical properties. This systematic approach will allow for profoundly understanding the correlation between composition and network architecture of the SiOC-based ceramics and their high-temperature creep behavior and consequently for rationally designing polymer-derived ceramics with tailored microstructure and properties.