Fabrication of novel glasses and glass micro-spheres by acoustic levitation and laser heating.

通过声悬浮和激光加热制造新型玻璃和玻璃微球。

基本信息

批准号：
EP/V001736/1
负责人：
Adrian Barnes
金额：
$ 65.92万
依托单位：
University of Bristol
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2020
资助国家：
英国
起止时间：
2020 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FV001736%2F1
关键词：
Fabrication novel glasses glass micro

项目摘要

Oxide glasses have been important materials for millennia. Their transparency at optical wavelengths makes them ubiquitous in windows for houses and cars and their use in lenses for microscopes and telescopes has been key to much scientific development. Today they remain key technological materials with additional applications in, for example, the hard glasses used in mobile phone screens, the fibre optics that underpin current high-speed communications and as laser host materials to name a few.The process of making a typical oxide glass involves melting the material and allowing it to cool (quench) into a form in which the atoms have a disordered, non-crystalline arrangement. In practice, this non-crystalline form is difficult to achieve for most materials, apart from those that contain significant quantities of silicon dioxide, boron oxide or phosphorus oxide. In order to produce glasses with improved properties (e.g. refractive index, infrared transmission, rare-earth ion content ...) these components need to be avoided which has a significant impact on their glass forming ability. Hence, new methods for glass fabrication are required. The ability of a material to form a glass reliably depends on how fast it can be cooled (the quench rate), the container it is in and the presence of any solid impurities (that promote crystallization). The rate at which a very hot material will cool freely in air by radiation depends on its size. Hence to improve the quench rate for a given material we need to make it as small as possible. To avoid crystallization due to a container we need to use either, a very smooth container, or no container at all. Hence to discover and produce new glassy materials it is ideal to work with small samples under containerless conditions.In this project we will develop acoustic levitation methods to allow us to process materials at high temperatures without the need for a container. In this project we will exploit new techniques that have been developed recently in Bristol. In particular, we will develop further the 'TinyLev' device that allows routine levitation of materials with moderate density (up to 5 g. cm-3) and auto-tuning Langevin Horn based devices for use with high density materials (in excess of 12 g. cm-3).To achieve high melt temperatures we will use an aligned carbon dioxide laser system to heat the samples to temperatures in excess of 2500K. The use of a laser heating system means that the samples may be heated and melted in a matter of seconds with small thermal gradients. As a heat source the lasers may be switched off instantaneously so that the sample will be free cooled at its maximum rate so that for a size of less than 1mm diameter, quench rates of the order of 10,000 Kelvin/second will be achieved. The system will be very suitable for rapid processing/prototyping of new glass materials.The acoustic levitation and laser heating systems will be used to study the structure of novel silica-free glass forming systems, based on aluminium oxide, titanium oxide and gallium oxide, by X-ray and neutron diffraction. In particular, we will use the system to follow, in situ, the evolution of the liquid structure as it is rapidly cooled, to form either a glass or to observe the processes giving rise to crystal nucleation. The experiments will be coupled with state-of-the-art computer simulations to give new insight into the glass forming process.There is increasing interest in the use of high quality glass spheres with sizes of the order 10-100 microns diameter for applications in Whispering Gallery Mode (WGM) devices such as biosensors, temperature sensors and lasers. This acoustic levitation and laser heating system will be ideal to produce these spheres and the final part of this project will be to explore and evaluate this method for producing WGM spheres for these applications.

氧化物眼镜一直是数千年的重要材料。它们在光波长方面的透明度使它们在房屋和汽车的窗户中无处不在，并且在显微镜和望远镜的镜头中使用它们是许多科学发展的关键。如今，它们仍然是关键的技术材料，例如手机屏幕中使用的硬眼镜，基础电流高速通信的光纤以及以激光宿主材料为单便的光纤。制造典型的氧化物玻璃的过程涉及将材料融化并允许其冷却（quench），以使其冷却（Quench），使其成为一种不混乱的综合效果，并将其放置为无序的层次。实际上，除了包含大量二氧化硅，氧化硼或氧化磷的材料外，这种非结晶形式很难实现。为了产生具有改善特性的玻璃（例如折射率，红外传输，稀土离子含量...），需要避免这些组件，这对它们的玻璃形成能力产生了重大影响。因此，需要新的玻璃制造方法。材料形成玻璃的能力可靠地取决于其冷却的速度（淬火速率），其所在的容器以及任何固体杂质的存在（促进结晶）。非常热的材料通过辐射在空气中自由冷却的速度取决于其尺寸。因此，要提高给定材料的淬火率，我们需要使其尽可能小。为了避免由于容器而导致的结晶，我们需要使用一个非常光滑的容器或根本没有容器。因此，要发现和生产新的玻璃材料，是在无容器条件下使用小样品的理想选择。在此项目中，我们将开发声音悬浮方法，使我们能够在高温下处理材料而无需容器。在这个项目中，我们将利用最近在布里斯托尔开发的新技术。特别是，我们将进一步开发“ TinyLev”设备，该设备允许在密度中等密度（最高5g。cm-3）和自动调整Langevin Horn基于高密度材料的材料（超过12g。cm-3）（超过12g。cm-3）的材料。激光加热系统的使用意味着可以在几秒钟内用较小的热梯度加热样品和融化。作为热源，激光器可以立即关闭，以便以最大速率自由冷却，以使直径小于1mm的尺寸，将达到10,000 kelvin/秒的淬火率。该系统将非常适合于新玻璃材料的快速加工/原型化。声音和激光加热系统将用于研究基于X射线和中子衍射的新型无硅玻璃形成系统的结构，该结构基于氧化铝，氧化钛和氧化铝，基于氧化铝氧化铝，氧化钛和氧化甲壳虫的结构。特别是，我们将使用该系统在原位遵循液体迅速冷却的液体结构的演变，以形成玻璃或观察产生晶体成核的过程。该实验将与最先进的计算机模拟结合起来，以提供对玻璃形成过程的新见解。在使用尺寸为10-100微米的高质量玻璃球体中，对于在窃窃私图库模式（WGM）设备（例如生物传感器，温度传感器和激光器）中的应用中，具有尺寸为10-100微米的高质量玻璃球。这种声学悬浮和激光加热系统将是生产这些球体的理想选择，该项目的最后部分是探索和评估为这些应用生产WGM球的方法。