CAREER: Complex Lead Oxides as Corrosion Films and Extended Inorganic Hybrids

铅及其合金的羧酸腐蚀是导致风琴管等历史文物退化的主要原因。复杂的铅氧化物羧酸盐形式作为该腐蚀过程的产物，并构成了结构丰富但未充分研究的化合物家族。该项目由固态和材料化学计划支持，对腐蚀膜的生长和组成进行分析，并对氧化铅羧酸盐腐蚀产物及其相关合成相进行先进的结构表征。实验室暴露研究将确定铅锡合金对羧酸侵蚀的敏感性如何取决于合金成分和湿度。氧化物腐蚀膜中的相鉴定、元素绘图和高分辨率氧化态鉴定将深入了解每种金属在腐蚀过程中的作用。该项目旨在将铅锡合金的羧酸侵蚀从现象学理解为机械学。模型研究将通过分析真实的器官管道样本和使用器官病例的环境数据与人工制品退化联系起来。将采用水热法合成一系列的铅氧化物羧酸盐，观察到的腐蚀产物形成的基础。这些混合材料包含基于边共享Pb 4 O四面体的无限组件。部分电荷模型将提供洞察的解决方案的影响，管理形成不同的0，1，和2-D Pb 4 O为基础的架构。207 Pb NMR将补充X射线衍射表征Pb 2+孤对立体活性。该项目发生在一个主要的本科院校，并集中在本科研究人员的参与。该研究在艺术保护领域的应用将被用作本科非科学专业和跨学科K-12外展教育综合计划的基础。非技术总结：铅及其合金的腐蚀会导致铅酸电池和历史上的风琴管等各种物体的性能损失。特别是鉴于其毒性，充分了解铅与环境的相互作用及其腐蚀产物的化学性质至关重要。该项目由固态和材料化学计划支持，将使用实验室暴露实验以及真实样品的表征来阐明铅锡合金管风琴管腐蚀的原因和机制。作为腐蚀产物形成的化合物以及相关的合成相将进行详细的结构分析。其成果将应用于保护音乐会和录音中所欣赏的具有重要文化意义的器官，这些器官因其与着名作曲家的联系而受到音乐学家的珍视，并被视为前工业手工艺和技术的物理文件。该项目将在奥伯林学院进行，这是一所以本科为主的学院，有着为学生的研究生学习和科学职业做准备的悠久传统。本科生将是项目研究各个阶段的主要参与者。 他们将接受材料表征技术的培训，这些技术在规范化学课程中并不总是遇到。PI将利用项目研究和艺术保护之间的联系作为艺术材料化学非科学专业本科课程的起点。通过与奥伯林的合作？的全国公认的艾伦纪念艺术博物馆（AMAM），在课程中的学生将产生书面，音频和动手工具，以创建一个博物馆的材料之旅。这些媒体将在AMAM？建立了K-12外展计划。

TECHNICAL SUMMARY:Carboxylic acid corrosion of lead and its alloys is a major cause of degradation of historic cultural objects such as organ pipes. Complex lead oxide carboxylates form as products of this corrosion process and constitute a structurally rich yet understudied family of compounds. This project, supported by the Solid State and Materials Chemistry program, pairs analysis of the growth and composition of corrosion films with advanced structural characterization of lead oxide carboxylate corrosion products and their related synthesized phases. Laboratory exposure studies will establish how susceptibility of lead-tin alloys to carboxylic acid attack depends on alloy composition and humidity. Phase identification, elemental mapping, and high-resolution oxidation state identification in oxide corrosion films will provide insight into the role of each metal in the corrosion process. The project aims to move understanding of carboxylic acid attack of lead-tin alloys from the phenomenological to the mechanistic. Model studies will be linked to artifact deterioration through analysis of authentic organ pipe samples and use of environmental data from organ cases. Hydrothermal methods will be employed to synthesize a family of lead oxide carboxylates, for which observed corrosion products form the basis. These hybrid materials contain infinite components based on edge-sharing Pb4O tetrahedra. The partial charge model will provide insight into the solution influences governing formation of diverse 0-, 1-, and 2-D Pb4O-based architectures. 207Pb NMR will complement X-ray diffraction in characterization of Pb2+ lone pair stereoactivity. This project takes place at a primarily undergraduate institution and is centered on the participation of undergraduate researchers. Applications of the research to the field of art conservation will be used as the basis for an integrated program of education of undergraduate non-science majors and interdisciplinary K-12 outreach. NON-TECHNICAL SUMMARY:Corrosion of lead and its alloys leads to loss of performance in objects as varied as lead acid batteries and historic organ pipes. Particularly in light of its toxicity, full understanding of the interactions of lead with its environment and the chemistry of its corrosion products is critical. This project, supported by the Solid State and Materials Chemistry program, will use laboratory exposure experiments, as well as characterization of authentic samples, to elucidate the causes and mechanisms of corrosion of lead-tin alloy organ pipes. Compounds that form as corrosion products, as well as related synthesized phases, will be subjected to detailed structural analysis. Outcomes will have applications to the conservation of culturally important organs that are enjoyed in concerts and recordings, treasured by musicologists for their ties to notable composers, and valued as physical documents of pre-industrial handcraft and technology. This project will take place at Oberlin College, a primarily undergraduate institution with a strong tradition of preparing students for graduate study and careers in science. Undergraduate students will be the primary participants in all phases of the project research. They will receive training in techniques of materials characterization that are not always encountered in the canonical chemistry curriculum. The PI will use the link between the project research and art conservation as the starting point for an undergraduate course for non-science majors on the chemistry of art materials. Through partnership with Oberlin?s nationally recognized Allen Memorial Art Museum (AMAM), students in the course will produce written, audio, and hands-on tools to create a materials tour of the museum. These media will be implemented in the AMAM?s established K-12 outreach program.