Role of Selected Major and Minor Alloy Alloying Elements in Copper Alloys on Copper Ion Release and Oxide Formation for Anti-Microbial Functionality

技术概述：耐甲氧西林金黄色葡萄球菌(MRSA)对抗生素耐药，通过与金属表面的手面接触传播，经常导致医院患者感染。铜(铜)和银(银)具有抗微生物的能力，这是因为在潮湿的空气中汗液盐沉积形成复杂的表面环境时，被氧化的铜或银离子通过电化学过程释放出来。由于手汗液引起的快速变色，铜表面目前在医院中并不受欢迎。具有抗菌能力和颜色稳定性的铜合金非常适合目前使用不锈钢但没有抗菌能力的高触摸面。理想的合金表面通过合金化以一定的速率释放出铜离子。然而，对铜合金的电化学氧化、钝化和释放的科学认识还存在差距。以往的研究很少集中在主要和次要合金元素对合金中铜释放的影响上。以前对商业合金的研究证实了合金元素的复杂效应；合金元素可能通过目前尚不清楚的机制抑制或促进铜离子的释放。目的是阐明合金元素系统变化所导致的铜合金中铜的释放特征和机制。采用系统添加合金元素合成的二元和三元铜合金，研究合金化对铜释放、钝化和颜色稳定性的影响。腐蚀/释放行为将与氧化过程中合金元素去向的原子尺度测量有关。使用各种技术进行的全球和高分辨率表面和原子尺度的实验研究都将跟踪铜在金属中的命运、氧化物以及释放的熔剂。智力上的优势包括对主要和次要合金元素在这些过程中的作用的新的固/液界面的理解。将出现改进试验和错误方法的功能合金设计的基础。非技术总结：该项目涉及发展材料科学，从而能够更好地设计具有抗微生物功能的铜和银基合金，作为最终控制医院获得性感染的方法。例如，耐甲氧西林金黄色葡萄球菌(MRSA)对抗生素具有耐药性，通过手与面接触传播，经常导致感染。铜(铜)和银(银)金属合金具有抗微生物功能，因为金属离子在人体汗液等复杂的化学环境中会释放出来。由于手汗液导致的快速变色，CU在医院并不受欢迎。不锈钢可防止变色，但不具有任何抗菌能力。该项目旨在确定和了解控制合金性能的因素，使抗菌功能和颜色稳定性得以实现。这些特性对于高接触表面来说是非常理想的。本项目将进行研究，以确定选定的铜合金中铜的释放特征和机制，并由选定的合金化元素介导。智力上的优势包括对合金元素在铜合金氧化/人体汗液离子释放中的作用的新理解。这将使合金成分的智能设计成为可能，从而实现理想的抗微生物功能和最小的变色。更广泛的影响包括发展必要的洞察力，使多功能铜合金能够在抗微生物应用中使用，以减少致病细菌的传播。这可以对世界健康产生积极的影响，也有助于理解金属在其他应用中的释放。材料科学和工程以及腐蚀科学领域将出现重大的人力资源开发，这是STEM培训中的关键空白，也是美国国家科学院确定的国家需求。材料科学领域的研究生将接受教育，并完全融入所有研究任务。本科生和高中生也将参加。目前正在与美国铜发展协会和各种铜合金生产商进行合作。

TECHNICAL SUMMARY: Methicillin-resistant Straphylococcus aureus (MRSA) is antibiotic-resistant and spread by hand-to-surface contact with metal surfaces, often leading to hospital patient infection. Copper (Cu) and silver (Ag) possess anti-microbial capability due to the release of either oxidized Cu or Ag ions via electrochemical processes in response to complex surface environments formed during deliquescence of perspiration salt deposits in humid air. Cu surfaces are not presently favored in hospitals due to rapid tarnishing caused by hand perspiration. A Cu alloy that has antimicrobial capability and color stability is highly desirable for high touch surfaces where stainless steel is now used but has no antimicrobial capabilities. The ideal alloy surface releases Cu ions at rates mediated via alloying. However, there is a gap in scientific understanding of electrochemical Cu oxidation, passivity and release from copper alloys. Few past studies focus on the role of major and minor alloying elements on Cu release from alloys. Prior research on commercial alloys confirms the complex effects of alloying elements; alloying elements may either suppress or enhance release of Cu ions by mechanisms which are presently unknown. The objective is to elucidate the Cu release characteristics and mechanisms in selected Cu alloys as mediated by systematic variation of alloying elements. The effects of alloying on copper release, passivity and color stability will be investigated using binary and ternary Cu alloys synthesized with systematic additions of selected alloying elements. Corrosion/release behavior will be connected with atomic scale measurements of the fate of alloying elements during oxidation. Both global and high resolution surface and atomic scale experimental studies using a variety of techniques will track the fate of Cu in the metal, the oxide as well as the flux released. Intellectual merits include new solid/liquid interfacial understandings of the role of major and minor alloying elements on these processes. A foundation for functional alloy design that improves trial and error approaches will emerge.NON-TECHNICAL SUMMARY: This project concerns developing the materials science which enables better design of copper and silver based alloys that have anti-microbial functionality as a way to ultimately control hospital acquired infections. For instance, Methicillin-resistant Straphylococcus aureus (MRSA) is antibiotic-resistant and spread by hand-to-surface contact, often leading to infection. Copper (Cu) and silver (Ag) metallic alloys possess anti-microbial function due to the release of metal ions in response to complex chemical environments such as human sweat. Cu is not favored in hospitals due to rapid tarnishing caused by hand perspiration. Stainless steels resist tarnishing but do not possess any antimicrobial capability. This project seeks to identify and understand factors controlling alloy properties that enable both antimicrobial function and color stability. These properties are highly desirable for high touch surfaces. This project will conduct research to define the Cu release characteristics and mechanisms in selected Cu alloys as mediated by selected alloying elements. Intellectual merits include new understandings of the role of alloying elements on copper alloy oxidation/ion release in human perspiration. This will enable intelligent design of alloy compositions for ideal anti-microbial function and minimal tarnishing. Broader implications include development of the insight necessary to enable use of multi-functional copper alloys in anti-microbial applications to reduce the spread of disease-causing bacteria. This can positively affect world health, and also contribute to understanding of metal release in other applications. Significant human resource development will occur in the fields of materials science and engineering as well as corrosion science - crucial gaps in STEM training and a national need identified by the US National Academy. Graduate students in the materials science area will be educated and fully integrated with all research tasks. Undergraduate as well as high school students will also participate. Collaboration is underway with the Copper Development Association of America and various copper alloy producers.