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GOALI: Fundamental Investigations of Nucleation Processes in Silicate Liquids and Glasses with a Goal of Developing Predictive Models for Glass Formation and Crystallization

GOALI：硅酸盐液体和玻璃中成核过程的基础研究，目标是开发玻璃形成和结晶的预测模型

基本信息

批准号：
1720296
负责人：
Kenneth Kelton
金额：
$ 52.41万
依托单位：
Washington University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-07-15 至 2023-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1720296&HistoricalAwards=false
关键词：
GOALI Fundamental Investigations Nucleation Processes

项目摘要

NON-TECHNICAL DESCRIPTION: Glasses have been centrally important technological materials for thousands of years. Glass ceramics (partially crystallized glasses) are also important, filling low technology applications such as stove-tops and cookware, to high technology applications such as optical waveguides, telescope mirrors, bone prosthesis and dental restorations. Used in composite armor, ceramics are able to break up impacting projectiles while a metallic backing plate absorbs the kinetic energy of the projectile. Controlling nucleation, the first step in the crystallization of a liquid or glass, is critically important for the production of glass ceramics. However, nucleation is generally understood within the context of a model that was developed for liquid formation in a gas in the early years of the last century and extended to the crystallization of liquids about 60 years ago. This model is inadequate for the level of control needed today. The previous assumptions are now questionable and so predictions often fail to agree quantitatively with experimental data. This research is aimed at developing a deeper understanding of crystal nucleation and the formulation of a more quantitative model. This new model provides a foundation for the development of computer simulations that can be used to accelerate the discovery and design of new glasses and ceramics. The project provides opportunities for graduate students to interact with industrial scientists in Corning Research and Development and leads to a career path for graduates in either industry or academia.TECHNICAL DETAILS: Glasses and glass ceramics are ubiquitous modern materials, fundamental to a wide range of applications. Understanding nucleation and growth is critical in the production of high quality glasses and ceramics and the discovery of new ones. These processes must be precisely controlled to produce the desired devitrified microstructures, including the number, type, and size of crystallites formed in the glass. Currently, gaining this control is largely empirical, resulting in long development times for new products. Glass and glass ceramics companies are therefore working to develop improved measurement and modeling capabilities, and to increase the fundamental understanding of nucleation and growth processes at or beyond the state-of-the-art in the field. This research, carried out with scientists in Corning Research and Development, focuses on the development of a deeper understanding of crystal nucleation through a coordinated experimental/modeling approach for two model silicate glasses (Ba2O-2SiO2 and Na2O-2CaO-3SiO2) Key elements include scanning calorimetric surveys to determine the temperature range of significant nucleation, measurements of the time-dependent nucleation rates as a function of temperature, X-ray and elastic neutron scattering studies of the glass and nucleating crystal phases to assess the importance of glass structure on the nucleation barrier, extending the classical theory of nucleation to include the effects of the diffuse interface between the nucleus and the liquid/glass and to take into account ordering in the liquid/glass, and incorporating computer models and simulations to test these theories. The new insights gained lay the foundation for computer models that can guide the rapid development of new glasses and glass ceramics with an optimized microstructure. These activities mirror a broad approach for accelerated materials development that is a national priority. The US is in crisis, with a decreasing number of students seeking careers in science, technology, engineering and math (STEM). This research forms an integral part of graduate student training, both in an academic and industrial environment. This project exposes students to cutting edge glass production and characterization techniques and leads to an optimal career path for graduates.

非技术描述：几千年来，玻璃一直是重要的核心技术材料。玻璃陶瓷（部分结晶玻璃）也很重要，从灶台和炊具等低技术应用到光学波导、望远镜镜、骨假体和牙齿修复等高技术应用。在复合装甲中，陶瓷能够分解冲击弹丸，而金属背板则吸收弹丸的动能。控制成核是液体或玻璃结晶的第一步，对玻璃陶瓷的生产至关重要。然而，成核通常是在一个模型的背景下被理解的，这个模型是在上个世纪早期为气体中的液体形成而发展起来的，并在大约60年前扩展到液体的结晶。这种模式不足以满足当今所需的控制水平。以前的假设现在是有问题的，因此预测往往不能在数量上与实验数据一致。本研究旨在加深对晶体成核的理解，并建立更定量的模型。这一新模型为计算机模拟的发展提供了基础，可用于加速新玻璃和陶瓷的发现和设计。该项目为研究生提供了与康宁研发部门的工业科学家互动的机会，并为毕业生在工业界或学术界的职业发展铺平了道路。技术细节：玻璃和玻璃陶瓷是无处不在的现代材料，是广泛应用的基础。了解成核和生长对高质量玻璃和陶瓷的生产以及新产品的发现至关重要。这些过程必须精确控制，以产生所需的非氮化微结构，包括玻璃中形成的晶体的数量、类型和大小。目前，获得这种控制很大程度上是经验性的，导致新产品的开发时间较长。因此，玻璃和玻璃陶瓷公司正在努力开发改进的测量和建模能力，并增加对该领域最先进的成核和生长过程的基本理解。本研究由康宁研发部的科学家共同完成，重点是通过对两种模型硅酸盐玻璃（ba20 - 2sio2和na20 - 2cao - 3sio2）的协调实验/建模方法，加深对晶体成核的理解。主要内容包括扫描量热测量，以确定显着成核的温度范围，测量随时间变化的成核速率作为温度的函数，x射线和弹性中子散射研究玻璃和成核晶体相，以评估玻璃结构对成核势垒的重要性，扩展经典成核理论，包括核和液体/玻璃之间的扩散界面的影响，并考虑到液体/玻璃中的有序，并结合计算机模型和模拟来验证这些理论。获得的新见解为计算机模型奠定了基础，该模型可以指导具有优化微观结构的新型玻璃和玻璃陶瓷的快速发展。这些活动反映了作为国家优先事项的加速材料发展的广泛方法。美国正处于危机之中，寻求科学、技术、工程和数学（STEM）职业的学生数量正在减少。这项研究是研究生培训的一个组成部分，无论是在学术环境还是在工业环境中。该项目让学生接触到最前沿的玻璃生产和表征技术，并为毕业生提供最佳的职业道路。