Structure-Properties-Relationships in Lithiumaluminosilicate Glass Ceramics Containing High Concentrations of Nucleation Agents

含有高浓度成核剂的锂铝硅酸盐玻璃陶瓷的结构-性能-关系

• 批准号: 265468261
• 负责人: Professor Dr. Thomas Höche
• 金额: --
• 依托单位: Fraunhofer-Institut für Mikrostruktur von Werkstoffen und Systemen (IMWS)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/265468261?language=en
• 关键词: Structure; Properties; Relationships; Lithiumaluminosilicate; Glass; Structure; Properties; Relationships; Lithiumaluminosilicate; Glass

Tailored crystallization of glasses allows synthesis of a specific class of inorganic functional materials - glass-ceramics. As an example, ceramming of parent glasses based on Li2O/Al2O3/SiO2 (LAS) may lead to glass-ceramics with zero thermal expansion, the latter material is widely used in cooktop panels. A crystallization of MgO/Al2O3/SiO2 (MAS)-based glasses, on the other hand, may lead to glass-ceramics with high hardness and/or bending strength. The proposed research project is aimed to combine the useful macroscopic properties of the commercially most relevant LAS- and MAS-silicate glass-ceramics by precise control of their micro- and nanostructure. In particular, it shall be tried to gain excellent mechanical properties in LAS glass-ceramics that remain unrealized thitherto. Robust LAS glass-ceramics are very desirable, especially in combination with zero thermal expansion. To design glass-ceramics with nanoscaled crystalline phases for applications as desired, a profound understanding of the underlying nucleation and crystallization mechanisms is imperative. As such, especially a combination of contradictory properties - high hardness and zero thermal expansion - will only be realized based on a fundamental understanding of the associated processes. Comprehensive initial studies concerning MAS parent glasses with ZrO2 as nucleation agent have shown that the mechanisms which may lead to glass-ceramics with excellent mechanical properties are manifold. Besides phase changes, selective precipitation of crystalline phases with high coefficient of thermal expansion may also result in glass-ceramics of high hardness, whereas the addition of Y2O3 can stabilize the residual vitreous phase and suppress a quartz crystallization, yet still lead to glass-ceramics with excellent properties. These findings shall be deepened, and a direct comparison to nucleation- and crystallization phenomena in LAS-based glass-ceramics shall be drawn. In doing so, the planned experiments will be restricted to model glass systems with only a few components, to suppress the influence of minority components. LAS-based glasses with ZrO2 as nucleation agent only, but with defined, yet higher-than-usual nucleation agent concentration, shall be molten, cerammed and characterized in terms of physical properties and respective microstructure. Using distinct nanoanalytical methods, a comparison of the temporal evolution of crystallization in non-isochemical LAS- and MAS-based glasses shall be drawn, with a special emphasize on the early nucleation stages. Additionally, Y2O3 shall be added to chosen LAS parent glass compositions, to analyze its influence on crystal phase evolution, stabilization of the residual vitreous phase, and the mechanical properties of the resulting glass-ceramics. The planned investigations shall support a comprehensive picture of the crystallization mechanisms in silicate glass-ceramics.

量身定制的玻璃结晶允许合成特定类别的无机功能材料 - 玻璃陶瓷。例如，基于LI2O/AL2O3/SIO2（LAS）的父玻璃的施法可能会导致玻璃陶瓷具有零热膨胀的玻璃陶瓷，后一种材料被广泛用于Cooktop面板中。另一方面，MGO/AL2O3/SIO2（MAS）玻璃的结晶可能导致具有高硬度和/或弯曲强度的玻璃陶瓷。拟议的研究项目旨在通过精确控制其微型和纳米结构来结合商业上最相关的Las和silication玻璃陶瓷的有用宏观特性。特别是，应尝试在未实现的thitherto中获得LAS玻璃陶瓷的出色机械性能。强大的LAS玻璃陶瓷非常可取，尤其是与零热膨胀结合使用。为了根据需要使用纳米晶体相的玻璃陶瓷，对潜在的成核和结晶机制有深刻的理解是必须的。因此，尤其是相互矛盾的特性（高硬度和零热膨胀）的组合只能基于对相关过程的基本理解来实现。关于用ZRO2作为成核剂的MAS父玻璃的全面初始研究表明，可能导致具有出色机械性能的玻璃陶瓷的机制是多方的。除了相变变，具有高热膨胀系数的结晶相的选择性沉淀也可能导致高硬度的玻璃陶瓷，而添加Y2O3可以稳定残留的玻璃体相，并抑制石英结晶，但仍会导致具有出色特性的玻璃陶瓷。这些发现应加深，并与基于LAS的玻璃陶瓷中的成核和结晶现象进行直接比较。这样一来，计划的实验将仅限于仅具有少数组件的玻璃系统模型，以抑制少数群体的影响。基于LAS的玻璃仅作为成核剂，但具有定义但比异常的成核药物浓度更高的玻璃，应熔化，陶瓷和以各自的微观结构为单位。使用不同的纳米分析方法，应绘制非化学LAS和MAS基玻璃中结晶的时间演化的比较，并特别强调早期成核阶段。此外，应将Y2O3添加到选定的LAS父玻璃成分中，以分析其对晶体相化的影响，残留玻璃相的稳定以及所得玻璃陶瓷的机械性能。计划的研究应支持硅酸盐玻璃陶瓷中结晶机制的全面图片。