Capital investment in an Instrument to Measure Particle Size Distribution (PSD)

我们建议采购一种专用仪器，用于测量湿磨料浆中的粒度分布（PSD）。这将在两个STFC资助的项目中优化金属精细抛光工艺方面发挥至关重要的作用，并大大提高英国满足英国和国际科学基地仪器要求的能力。这包括望远镜和天文仪器的光学器件，从微波到X射线，高功率激光系统，同步加速器反射镜和其他应用。第一个项目涉及抛光软材料的非常困难的挑战，如铝，用于地面和空间天文学的反射镜和许多其他应用。第二类涉及硬材料，如用于工业大规模生产的工具钢中的复杂模具。“化学镀镍”福尔斯的特殊情况落在项目之间的边界上--它是一种硬金属涂层，有时作为薄层涂在铝镜上，以便于抛光和增加耐用性，或者涂在模具上，以复制用于X射线成像的薄壳镜。在开发这些工艺时，研磨抛光浆料有一个关键特性，我们目前还没有相关信息：- 磨料颗粒的尺寸分布。是否有一个硬的最大尺寸，或者有一些较大的颗粒，可以损坏表面？工作浆料中的颗粒是聚集在一起（“聚集”），还是破碎（“碎片”），还是较大的颗粒沉淀出来，搅拌在实现颗粒均匀分布方面的作用是什么？重要的是，抛光液是否被任何可能干扰抛光过程的物质污染（例如，降低表面粗糙度，导致划痕或凹陷等）。在任何材料上抛光期间PSD的变化还有另一个后果，无论是金属，玻璃还是玻璃陶瓷-它可以改变材料去除的速率，这被认为是工艺无法完全预测的原因之一。这反过来又会影响制造的时间、成本和实际风险。我们选择的仪器既经济又通用。它有两种用途：第一，它可以测量通过循环泥浆管理系统回流管的未稀释泥浆。这将给出关于浆料PSD的实时数据。其次，它可以与样品容器一起部署在工作台上-非常适合定期评估不循环但用于“全损耗”系统的专业浆料的小样品。考虑到精细抛光磨料的尺寸通常为2微米或更小，所选仪器可以测量非常合适的粒度范围-从约10微米到约1纳米（约10个原子！）。它有望提供丰富的基本数据的过程，这是目前超出了我们和许多其他工作人员在该领域。这将为我们对流程如何运作的基本理解增加一个新的维度，帮助我们在竞争中保持领先地位，并使我们能够开发出上级和具有成本效益的流程。

We propose to procure a specialised instrument for measuring particle size distribution (PSD) in wet abrasive slurries. This will play a vital role in optimising processes for fine-polishing of metals in two STFC-funded projects, and materially enhance UK capability to meet instrumentation requirements of the British and International Science Base. This embraces optics for telescopes and instruments for astronomy from microwaves to X-rays, high-power laser systems, synchrotron mirrors and other applications besides.The first project involves the very difficult challenge of polishing soft materials such as aluminium, used for mirrors in ground-based and space astronomy and many other applications. The second concerns hard materials such as complex moulds and dies in tool-steels, used for industrial mass production. The specific case of 'electroless nickel' falls on the boundary between the projects - it is a hard metal coating, sometimes applied as a thin layer to aluminium mirrors for ease of polishing and increased durability, or on moulding dies to replicate the thin shell-mirrors used for X-ray imaging.In developing these processes, there is a key property of abrasive polishing slurries about which we currently have no information:- the distribution of the sizes of the abrasive particles. Is there a hard-maximum size, or are there a few larger particles that can damage surfaces? Do particles in working slurry clump together ('agglomerate'), or break up ('fragment'), or do larger particles settle out, and what is the role of agitation in achieving a uniform population of particles? And of great importance, does the slurry become contaminated with anything that could disturb the polishing process (e.g. degrade surface-roughness, cause scratches or digs, etc). There is another consequence of a change in PSD during polishing on any material be it metal, glass or glass-ceramic - it can change the rate of material removal, and this is believed to be one reason why processes are not fully predictable. This in turn impacts the time, cost and indeed risk of manufacture. The instrument we have selected is both economic and versatile. It can be used in two ways: first, it can measure undiluted slurries as they pass through the return pipe of our recirculating slurry management system. This will give real-time data on the slurry PSD. Second, it can be deployed on the bench with a sample container - very suitable for periodically assessing small samples of specialist slurries which are not recirculated, but used in a "total-loss" system. Given that fine polishing abrasives are typically 2 micron in size or less, the selected instrument can measure over a very suitable range of particle sizes - from about ten microns down to about a nanometre (~10 atoms!). It promises to provide a wealth of fundamental data on processes, which is currently beyond the reach of both ourselves and many other workers in the field. This will add a new dimension to our basic understanding of how processes operate, help us to stay ahead of the competition, and enable superior and cost-effective processes to be developed.