Correlative Chemical Metrology

相关化学计量

• 批准号: EP/X019071/1
• 负责人: John Walker
• 金额: $ 25.74万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FX019071%2F1
• 关键词: Correlative; Chemical; Metrology

The interaction of surfaces is fundamental to how we live our lives. How surfaces behave when they move against each other as part of engineered components in machines depends to a large extend on what they are made from and how they are made. This is important because surfaces made from the wrong material or the wrong surface finish could cause the component to fail before it was designed to do so. This leads to a cost penalty for repair and replacement but there is also the additional energy wastage incurred as the material needs to be recycled and re-made. Thus measuring surface composition and roughness is quite important but to do so accurately involves lots of different scientific techniques which can make it time consuming and expensive. It would be much better from a sustainability perspective if surfaces could be measured quickly and accurately when they were being made at a relatively low cost to give information about both their composition and roughness.This project aims to try and achieve this goal by combining two scientific techniques into one sensor measurement. Roughness is often measured by tracing a diamond tip across a surface to measure differences in height. Diamond is a good material for doing this as it is very hard and is not easily damaged when in contact with surfaces. Diamond is an insulator but this can be changed if it is doped with boron. This makes the diamond conductive and means we could potentially use a technique called electrochemical impedance spectroscopy, or EIS, to measure changes in the contact resistance at different AC frequencies (called the impedance) between the diamond and an engineered surface like a steel. The impedance is likely to change as the probe moves across different parts of the steel structure, for example, it will probably be different for the iron part of the steel compared to a part that has lots of carbon in it. This means we might be able to correlate the high and low points of the roughness to the different materials phases of a surface.It will be quite challenging to achieve this as EIS take several minutes to scan all the AC frequencies, but measuring the topography only takes a few seconds. The influence of vibrations, thermal drift and relative humidity will need to be taken account of when the measurement is performed. The data will be collected from a very sensitive nano-indentation machine that uses capacitance plates to provide very accurate data of surface positions. The amount of water in the air when the measurements are taken will be controlled with a chamber than can be filled with dry nitrogen. This is because water in the air will desorb near the probe when the measurements are made and could allow impedance of ambient surfaces to be measured.If the technique were to work it could be very useful across a number of different sectors. These include manufacturing, where it might be used as a quality control device, checking that manufactured components have been made to the correct surface roughness and that no contamination of the surface is present. When some manufacturing processes go wrong they sometimes 'burn' or oxide the surface and this new sensor might be capable of detecting that before a human notices. Other sectors that could benefit would be the chemical industry, especially the catalysis sector, where the surface area of different catalytic species could be correlated to surface height, allowing optimisation for particular applications. This approach would also be relevant to engineering components that experience sliding or rolling contacts as the technique could determine how surfaces change in response to damage accumulation. This could be from both a surface engineering design optimisation point of view or indeed as a condition monitoring approach, where the surfaces are measuring in-situ within their application environment to warn of potential problems developing during operation.

表面的相互作用是我们生活的基础。作为机器中工程部件的一部分，表面相互运动时的行为在很大程度上取决于它们是由什么制成的以及它们是如何制成的。这一点很重要，因为由错误材料制成的表面或错误的表面光洁度可能会导致组件在设计之前失效。这导致了维修和更换的成本罚款，但也有额外的能源浪费，因为材料需要回收和重新制造。因此，测量表面成分和粗糙度是非常重要的，但要准确地做到这一点涉及到许多不同的科学技术，这可能会使它既耗时又昂贵。从可持续性的角度来看，如果能够以相对较低的成本快速准确地测量表面，从而提供有关其成分和粗糙度的信息，那就更好了。本项目旨在通过将两种科学技术结合到一个传感器测量中来尝试实现这一目标。粗糙度通常是通过在表面上追踪钻石尖端来测量高度的差异来测量的。金刚石是一种很好的材料，因为它非常坚硬，与表面接触时不易损坏。金刚石是绝缘体，但如果掺入硼，这种绝缘体可以改变。这使得金刚石具有导电性，这意味着我们有可能使用一种叫做电化学阻抗谱（EIS）的技术来测量金刚石和钢等工程表面在不同交流频率下接触电阻的变化（称为阻抗）。当探针穿过钢结构的不同部分时，阻抗可能会发生变化，例如，钢的铁部分与含有大量碳的部分相比，它可能会有所不同。这意味着我们可能能够将粗糙度的高点和低点与表面的不同材料相联系起来。这将是相当具有挑战性的，因为EIS需要几分钟来扫描所有的交流频率，但测量地形只需要几秒钟。在进行测量时，需要考虑振动、热漂移和相对湿度的影响。数据将从一台非常灵敏的纳米压痕机收集，该机器使用电容板提供非常精确的表面位置数据。测量时，空气中的含水量将由一个可以装满干氮气的容器来控制。这是因为在进行测量时，空气中的水会在探头附近解吸，从而可以测量环境表面的阻抗。如果这项技术能够发挥作用，它将在许多不同的领域发挥非常大的作用。这些包括制造，在那里它可能被用作质量控制装置，检查制造的组件已经被制造到正确的表面粗糙度，并且表面没有污染。当一些制造过程出现问题时，它们有时会“燃烧”或氧化表面，而这种新的传感器可能能够在人类注意到之前检测到这一点。其他可能受益的行业是化学工业，特别是催化行业，在该行业中，不同催化物质的表面积可以与表面高度相关，从而可以针对特定应用进行优化。这种方法也适用于经历滑动或滚动接触的工程部件，因为该技术可以确定表面如何响应损伤积累而变化。这可能是从表面工程设计优化的角度来看，也可能是作为一种状态监测方法，在应用环境中对表面进行现场测量，以警告在操作过程中出现的潜在问题。