快速动态原位合成AlSi基非晶涂层及其损伤行为研究

The operational reliability and service life of the key parts of marine engineering equipment have been seriously limited by corrosion and wear behaviors under marine environment. Thermal spraying technology is one of the key techniques for corrosion and protection of marine engineering. However, the type and quality of thermal spraying marine materials are short and deficient, which has become a bottleneck for long life protection system of ocean engineering. In order to improve performance and long life safety service of key components of marine engineering equipment, a series of AlSi-based metallic glass coatings were in situ synthesized by using high velocity electrical arc spray processing. The aim of this project is to investigate the heat transfer, deformation and other basic scientific problems of in-flight particles during arc-spraying. The formation mechanisms of the metallic glass coatings are also analyzed. The effects of the addition elements on improving amorphous content, reducing the oxide and enhancing wettability of AlSi-based coatings are explored in details. The corrosive behaviors of the AlSi-based metallic coatings with varied microstructure and surface characteristic are studied in simulated marine environment. The tribochemistry mechanisms on mechanics and chemistry synergism action of the coatings are illuminated. The life prediction model of the coating is established. In this interdisciplinary program, the material science, corrosion science and tribology analyses are included. This project could provide high efficient, energy-saving and environment friendly new protective materials and advanced technology support for prolonging service life and operational reliability of key parts of marine engineering equipment.

海洋环境下的腐蚀和磨损行为已严重影响着海洋工程装备关键部件运行可靠性和服役寿命，热喷涂技术是海洋工程腐蚀防护关键技术之一，但其海洋防护材料种类短缺与质量不足成为海洋工程长寿命防护体系的制约瓶颈。本项目拟以实现海洋工程装备关键部件高性能和长寿命安全服役为目标，基于高速电弧喷涂含非晶形成元素的粉芯丝材，在快速动态冶金过程中原位合成AlSi基非晶涂层：研究涂层制备中粒子传热/形变等基本科学问题，探讨非晶涂层原位形成机理；揭示添加元素对涂层提高非晶含量、降低氧化物及改善润湿性的科学机制；澄清涂层结构和表界面特性对其在模拟海洋环境因素下腐蚀损伤行为与机理；揭示非晶涂层在力学-化学协同作用下摩擦化学机制，构建涂层寿命预测模型。本项目研究内容体现了材料学、腐蚀、摩擦科学等多学科领域交叉，为延长海洋工程装备关键部件服役寿命和运行可靠性等方面提供高效、节能、环境友好的新型防护材料和先进再制造技术支撑。

本项目针对海洋工程装备关键部件的腐蚀与防护难题，自主研发了具有强非晶形成能力的AlFeSi粉芯丝材，采用自动化高速电弧喷涂技术在Q235钢基体表面原位合成了AlFeSi非晶涂层。研究了涂层的组织结构与非晶原位形成机制，揭示了涂层在NaCl溶液中的电化学腐蚀行为以及在力学-电化学作用下的损伤机制。结果表明，涂层呈现典型的层状结构，其结构致密，结合紧凑。涂层的非晶相含量为74.9％，孔隙率为1.2%，平均显微硬度为375 HV0.1，结合强度为36.4MPa。与晶态结构纯铝涂层相比，兼具疏水特性和非晶结构的AlFeSi涂层呈现出优异的耐蚀性能。随着浸泡时间的延长，非晶涂层的耐蚀性能呈现出先升高后下降的趋势；随着溶液温度和速度的升高，涂层的耐蚀性能逐渐降低。干摩擦条件下和腐蚀介质作用下，随着磨损线速度和外加载荷的增加，AlFeSi非晶涂层的磨损率均随之降低。高非晶含量和良好弹性性能的AlFeSi涂层具有优异的耐磨性能：干摩擦条件下，当磨损线速度为15mm/s，外加载荷为25N时，其耐磨性能为6061铝合金的4.3倍，非晶涂层的主要失效机制为脆性剥落和氧化磨损。腐蚀介质条件下，当磨损线速度为45mm/s，载荷为30N时，其耐磨性能为6061铝合金的4倍，其主要失效机制为脆性剥落和腐蚀损伤。本项目相关研究成果为最大限度延长海洋工程装备的服役寿命和运行可靠性等方面提供高效、节能、环境友好的新型再制造防护材料和先进技术支撑，这对降低重大灾害性事故的发生，发展我国海洋经济、建设海洋强国等方面具有重要的意义。