Processing of nano copper materials for the production of conductive circuits

铜、银和镍等纳米金属的分散体允许使用适当的印刷和固化/烧结工艺来生产导电电路。这种电子电路制造的附加方法允许以最少的浪费和更少的生产步骤来制造大面积器件。该技术在许多大面积市场中都有应用，包括光伏、电磁屏蔽、智能窗户、分布式电力系统和大型电池。印刷电路的主要材料是银，但这有成本和资源可持续性的限制。铜资源丰富，具有显著降低成本的潜力，但纳米铜的快速反应性会导致氧化，破坏铜的导电性。为了保持导电性，纳米铜必须经历一个快速的(？lt；1s)控制的纳米颗粒到块体铜的转变。这样，纳米粒子的聚合动力学比氧化动力学发生得更快。该项目将研究以与批量生产相适应的生产速度沉积和烧结纳米铜的方法。这将利用相关的印刷工艺(喷墨、丝网和静电沉积)和固化设备(激光、近红外、紫外线和脉冲白光)。性能的宏观变化的实验室研究需要与纳米铜的微观结构和成分的变化相关联。该项目最初将以纳米铜材料为目标，但其他技术，如快速还原氧化铜和分解铜络合物也可能在范围内。在制造了电路之后，还可以检查铜电路与其环境之间的相互作用，或者它与器件中其他材料(如有机导体)的相互作用。1.研究的主要目的/目的。该项目打算回答哪些问题？该项目旨在识别和了解纳米铜墨水在烧结过程中发生的物理和化学机理。该项目将解决纳米铜烧结机制与铜颗粒尺寸、温度、能量输入动力学速率和局部气体环境之间的内在关系。高活性的纳米铜颗粒经历了相互竞争的物理熔化和化学氧化过程，理想地从多孔性的纳米铜骨架过渡到共格的连续非氧化金属结构。了解材料和加工性能对烧结膜的影响是本研究的一个主要目标。将在项目过程中实施的新的物理科学/工程方法。学生们将做什么？该项目将通过在热和气体环境(惰性、空气和还原)中选择一种材料(粒度分布的变化)来研究烧结过程的工作范围。在这些烧结环境下的印刷样品将在导电性、附着力和接触电阻方面进行宏观评估。我们将结合原子力显微镜、X射线衍射仪、X射线光电子能谱和扫描电子显微镜等分析方法，对微观尺度上的机理进行鉴定。学生还将研究高速烧结工艺，如近红外线、激光和光子烧结，这些工艺具有潜在的生产率和碳足迹优势。通过改进方法的迭代研究，将检查这些潜在有吸引力的过程的潜力。这项工作将重点放在50x50 mm的玻璃基板上，以提供热稳定(在考虑的250摄氏度范围内)。在结尾处加上一句话来说明研究领域会很有帮助--请从项目材料(材料工程-金属和合金)及其与新制造技术的互动中选择可能的最终用户

Dispersions of nano-metals such as copper, silver and nickel allow the production of conductive circuitry using an appropriate printing and curing/ sintering process. This additive approach to electronic circuit manufacture allows large area devices to be manufactured with minimal waste and fewer production steps. The technology has applications in a number of large area markets including PV, EM shielding, smart windows, distributed power systems and large batteries. The dominant material for printed circuitry is silver but this has a cost and resource sustainability limitations. Copper is earth abundant and has the potential to significantly reduce cost but the rapid reactivity of the nano-copper leads to oxidation, destroying the conductivity of the copper. In order to sustain conductivity the nano-copper must undergo a rapid (<1s) controlled nano-particle to bulk copper transition. In this way the kinetics of nano particle coalescence occur more rapidly than the kinetics of oxidation. The project will examine means by which nano-copper can be deposited and sintered at production speeds which are compatible with volume manufacturing. This will utilize relevant printing process (inkjet, screen and electrostatic deposition) and curing equipment (laser, NIR, UV and pulsed white light). Laboratory studies of macro changes in properties will need to be correlated to changes in the micro structure and composition of the nano-copper. The project will initially target nano-copper materials, but other technologies such as rapid reduction of copper oxide and decomposition of copper complexes may also be within scope. Having produced circuitry, there is also scope for examining the interaction between the copper circuitry and its environment or its interaction with other materials in a device, such as organic conductors. 1. The key objectives/aims of the research. What questions does the project intend to answer?The project aims to identify and understand the physical and chemical mechanisms which occur during the sintering of nano copper ink. The project will address the inter relationship between the nano copper sintering mechanism and the copper particle size, temperature, kinetic rate of energy input and local gaseous environment. The highly reactive copper nano particles are subject to competing processes physical melting and chemical oxidation, with an ideal transition from a porous nano copper framework to coherent continuous un-oxidized metallic structure. Understanding the impact of material and processing properties on the sintered film is a key objective of the research study.2. The novel physical sciences/engineering methodology that will be carried out during the course of the project. What will the students be doing?The project will examine the working envelope of sintering process, through sintering of a selection of materials (variations in particle size distribution) within thermal and gaseous environments (Inert, air and reducing). Printed samples subjected to these sintering environments will be assessed macroscopically in terms of conductivity, adhesion and contact resistance. Identification of mechanisms on a micro scale will be examined using a combination of analytical methods including AFM, XRD, XPS and SEM. The student will also examine high speed sintering processes such as near infra-red, laser and photonic sintering which offer a potential productivity and carbon footprint benefit. Through iterative studies with refinement of methods, the potential of these potentially attractive processes will be examined. This work will focus on glass substrates of 50 x 50 mm to provide a thermally stable (over the 250C range considered).3. It would be helpful to include a sentence at the end identifying the research area - please select from The project materials lie within (Materials engineering - metals and alloys) and its interaction with novel Manufacturing technologies with a likely end user in the