荷温耦合对金属表面纳米再制造涂层作用机理研究

Remanufacturing of the metallurgical equipments is an important approach to the development of high-efficiency green steel industry. The durability and safety of metallurgical equipments are theoretically based on two key scientific issues, the cross-scale damage mechanism caused by both load and temperature and the behavior and mechanism of the coating interface, both unsolved up till now due to the current limitations in the study of surface analysis technology of the material failure. The key parts of the metallurgical equipments under the operating condition of both load and temperature are taken as the research object in this project, new remanufacturing coating process will be researched and developed, and functional nano-particles will be filled to realize the self-lubricating and self-repairing performance, the relationship between the evolution of fatigue damage, wear, corrosion from micro, mesoscopic to macro scale and the evolution of coating microtexture and microstructure will also be explored. The following four aspects will be studied in this project: the microscopic physical mechanism of cross-scale fatigue damage under the operating condition of both load and temperature; the cross-scale wear, corrosion damage behavior and mechanism under the operating condition of both load and temperature; the characteristics of metastable structure of remanufacturing parts' surface and coating interface; the self-lubricating and self-repairing behavior and mechanism of remanufacturing parts' coating surface. This project can provide basic theory for hot strip mill equipment key parts' remanufacturing under the condition of both load and temperature，and promote the development of new methods in remanufacturing research.

冶金设备再制造是实现高效绿色钢铁工业发展模式的重要途径，其涂层服役耐久性与安全性的重要理论基础是荷温耦合作用下跨尺度损伤机理和涂层表/界面行为与机理两个关键科学问题，由于现今表面分析技术在材料表面失效研究中的局限性，上述问题尚未解决。本项目针对热轧设备核心零部件，研究通过高速电弧喷涂工艺可控添加纳米WS2与BaF2-CaF2共晶协同剂实现其自润滑自修复功能，揭示跨微观-介观-宏观尺度的疲劳损伤、磨损、腐蚀与涂层显微组织和结构演变关联性,具体包括以下四个方面：荷温耦合作用下跨尺度疲劳损伤的微观物理机制；荷温耦合作用下跨尺度磨损、腐蚀损伤行为与机理；涂层界面的服役匹配行为、机理及设计；涂层表面自润滑与自修复作用行为与机理。本项目能够为荷温耦合作用下的热轧设备核心零部件再制造奠定理论基础，同时也促进再制造研究新方法的发展。

在高载荷、高温、高压长时间条件下工作的冶金设备，每年消耗大量的备品配件。针对其重载高温工作状况，以延长金属设备服役寿命为目标，有必要进行设备再制造的涂层应用研究。内容包括：有机聚酰亚胺、水性超薄防火涂层，其它四类有机树脂粘结涂层，激光重熔合金涂层，以及针对设备再制造的水性纳米转化带锈涂层。四类有机树脂粘结涂层中，又分别对比研究了二硫化钨包覆、微胶囊化二硫化钨、润滑油微胶囊涂层，分别研究了各自的摩擦磨损性能及其延寿服役机理。在此基础上，针对特殊高温场合和重腐蚀介质研究了PEI改性介孔二氧化硅和改性石墨烯/PANI防腐涂层的作用机理。.当滑石粉为2%、Al2O3为6%~8%时，含二硫化钨的聚酰亚胺涂层耐热性能和减摩耐磨性能最佳，含二硫化钨涂层的磨损机理以磨粒磨损为主。经KH550改性五个小时和经环氧树脂E44改性的涂层磨痕形貌较光滑，同时在涂层表面仍然保留有WS2粉末，涂层耐磨性能优良。.PAM包覆机油所形成的固体润滑涂层的磨损量与摩擦系数最小。分别采用密胺树脂和脲醛树脂包覆的两类润滑油微胶囊涂层显著提升了涂层摩擦学性能，适当的外壳强度可以保证在润滑试验中微胶囊有效地释放出足够的润滑油，保证涂层的润滑性能，本文首次提出的该独创性技术有利于微胶囊技术在摩擦学领域的推广应用。.利用聚乙烯亚胺对介孔TiO2进行改性，当meso-TiO2/PEI 为0.5g，水性环氧树脂10g，固化剂4g，水3g，涂层电阻Rc达到1217Ω·cm2。加入PGO/PANI填料，环氧树脂涂层附着力由3级提高到1级，腐蚀等级由6级提高到0级；通过Tafel曲线，复合涂层的腐蚀电压为-194.59mV、腐蚀电流为2.12×10-9A/cm2、电阻为3078.62KΩ·cm2以及防腐效率达到99.99%；PGO质量占PANI质量10%时防腐蚀效果提高2个数量级。.本文水性带锈转化涂料可直接涂刷于锈蚀钢铁表面，所含有效成分能与铁锈相互作用，将铁锈转化为涂层中具有独特螯合作用的稳定填料。以此为基础制得的系列涂料在马钢集团和南钢集团应用之后已经在船体和铁路器材推广应用。