Composition-structure-property relationship in tectosilicate solid solutions synthesized from glass

尽管在硅酸盐材料和玻璃结晶领域投入了大量的研究工作，但知识差距仍然存在，阻碍了对玻璃陶瓷技术中可能有利的材料系统的充分理解和详细评估。在这个项目中，我们的目标是通过基本的成分-结构-性质调查来弥补这些漏洞，重点研究三种特定的构造硅酸盐，即方英石、石英和白晶石的固溶体，由于它们的技术相关性、发展潜力和实验不充分而被选中。目标是通过利用玻璃的非平衡，动态冻结状态作为起始材料来实现，因为它允许在受控的再加热下探索热力学亚稳晶体相，否则不可能合成。因此，该方法遵循奥斯特瓦尔德的阶段规则，首先获得最不稳定的多晶（固溶体）。在玻璃形成方面，实验的目标是通过溶胶-凝胶喷雾干燥途径扩大熔融猝灭，以制备尽可能广泛的相关化学成分和浓度。一方面，工作组建立了用于玻璃制备和结晶过程中结构表征的适当仪器。通过它，通过在环境以及高温和低温（主要是XRD）下进行原位测量，可以深入了解所需固溶体晶体的演变及其结构。另一方面，该项目旨在充分了解所制备的固溶体晶体的晶体学约束，包括对已知晶体多晶的明确分配或发散以及它们的转变行为。就玻璃陶瓷技术而言，目标是通过详细评估相关性质（如热膨胀）来获得可能有利的系统和这些相的发展潜力的知识。

Despite the intensive research efforts that have been invested in the fields of silicate materials and glass crystallization, knowledge gaps still persist and prevent full understanding and detailed assessment of possibly advantageous materials systems in glass-ceramic technology. With this project, we aim at closing those loopholes through a fundamental composition-structure-property investigation, concentrating on three specific tectosilicates, i.e. solid-solutions of cristobalite, quartz and leucite that have been selected due to their technological relevance, their development potential and their experimental underdetermination. The objective is to be achieved by taking advantage of the non-equilibrium, kinetically frozen-in state of glass as a starting material, since it allows upon controlled reheating to explore thermodynamically metastable crystalline phases otherwise impossible to synthesize. Thereby the approach follows the Ostwald's rule of stages in accessing the least stable polymorph (solid solution) first. In terms of glass formation, experiments are targeted to prepare the widest possible range of relevant chemical components and concentrations by expanding melt-quenching with the sol-gel spray-drying route. On the one hand, the working group has established appropriate instrumentation for glass preparation and structural characterization during crystallization. Through it, insights will be gained into the evolution of desired solid solution crystals and their structure by performing measurements at ambient, as well as in-situ at high and cryogenic temperatures (mainly XRD). On the other hand, the project aims at fully understanding the crystallographic constraints of the prepared solid solution crystals including a clear assignment or divergence to known crystal polymorphs as well as their transformation behavior. In terms of the glass-ceramic technology, the objective is to gain knowledge on possibly advantageous systems and the development potential of these phases by a detailed assessment of relevant properties, such as thermal expansion.