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

聚合物衍生玻璃和微晶玻璃(PDC)在过去的40年里已经为人所知，并通过合适的聚合物的固态热分解来制备。由于它们的共价键和无定形性质，它们表现出独特的非凡性质的组合。氧化碳化硅(SiOC)三元PDC具有优异的高温(T&gT；1000°C)性能，如抗结晶和分解、抗氧化和耐腐蚀以及抗蠕变。它们的性质直接受到前体的化学和分子结构的影响。因此，通过使用定制的聚合物来调节聚合物衍生陶瓷的微观结构和性能具有巨大的潜力。本提案的目的是系统地研究硅氧碳化硅基聚碳酸酯的热物理性质和高温蠕变行为，在其对成分和纳米/微结构的依赖性的背景下。因此，将制备具有模型相组成和纳米/微结构的SiOC材料，并研究其在接近玻璃化转变温度下的力学性能。原子建模方法将补充实验，以证实具有特定机械性能的微观结构特征。这一系统的方法将有助于深入了解SiOC基陶瓷的组成和网络结构与其高温蠕变行为之间的关系，从而合理地设计具有定制的微结构和性能的聚合物衍生陶瓷。

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.