低温多效负压工艺下铝合金的腐蚀行为及金属配位驱动的防护机制研究

海水淡化是我国战略型新兴产业，低温多效（MED）海淡装置是大型负压热交换设备。铝合金热交换管成本低，MED工艺下铝合金的保护技术是我国海淡产业发展的关键之一。但是，对负压下铝合金热交换管的腐蚀行为尚需深入进行研究。本项目拟考察负压下海水气化蒸发、扩散及其对铝合金表面膜结构的影响。采用绿色缓蚀阻垢剂喹啉-2-羧酸和聚谷氨酸为模型化合物，其分子中含有氮、羧基等活性基团，能与多种金属离子（Cu2+、Fe3+等腐蚀性离子，Ca2+、Mg2+等结垢性离子）发生配位作用，具有相应的荧光发射。通过荧光显微成像技术，研究不同金属配合物的光谱行为及其在铝合金表面膜的荧光分形特征。结合微区电化学测量、表面分析和表面能计算，探讨MED使役条件下铝合金的腐蚀行为和缓蚀阻垢作用的新机制，获得MED工艺下铝合金缓蚀阻垢剂设计与筛选的理论，从而为大型MED装置铝合金热交换管应用技术开发提供指导。

Seawater desalination is a strategic emerging industry in China. Low-temperature multi-effect (MED) seawater desalination device is a large-scale negative pressure heat exchange equipment. Corrosion prevention of aluminum alloy heat exchange tube is the key problem restricting its industrial application in MED device. However, the corrosion characteristics and surface film structure of aluminum alloy under negative pressure need to be further studied. Quinoline compounds are the specific corrosion inhibitors of aluminum alloy. Polyamino acids are commonly used as . scale inhibitors in industrial water treatment. They are safe and non-toxic. This project intends to use quinoline-2 carboxylic acid and polyglutamic acid as the model compounds. There are nitrogen atom, carboxyl group and other corrosion and scale inhibiting active groups in its molecule. It can coordinate with a variety of metal ions (such as corrosive ions of Cu2+/Fe3+, scaling ions of Ca2+/Mg2+) to give the corresponding fluorescence emission. We plan to investigate the effect of seawater gasification and evaporation on the surface structure of aluminum alloy, and research the corrosion characteristics of aluminum alloy heat exchange tube under negative pressure. Through fluorescence spectrum and fluorescence microscopy, the spectral changes of different metal-complexes and their fractal characteristics on the surface film of aluminum alloy were studied. Combined with micro-area electrochemical measurement and surface analysis technology, the mechanism of corrosion inhibition and scale inhibition of aluminum alloy heat exchange tube under negative pressure will be discussed. It will provide a theoretical guidance for the development of the application technology of aluminum alloy heat exchange tube in the large-scale MED seawater desalination equipment.