Fe-B合金组相形态诱发界面“取向钉扎”效应及其耐锌液冲蚀-磨损机理

The serious corrosion of galvanizing equipment in liquid zinc is a key problem which restricts the development of galvanizing industry. It becomes a significantly important project in urgent need of solution currently. Microstructural morphologies and interfacial microstructures of corrosion-resistant phases in the corrosion-resistant materials are two critical factors which can affects the corrosion-resistant properties of materials in liquid zinc, and their efficient controls are the foundation of microstructural design and improving performance of materials in liquid zinc. Based on the unique microstructure of Fe-B alloy containing matrix plus corrosion-resistant skeleton of Fe2B, and considering the actual damage of galvanizing equipment produced by the erosion-corrosive wear characteristics of component surface in flowing liquid zinc, a new and novel idea on morphological efficient control between Fe2B and matrix as well as a strong interfacial structures of "orientation-pinning effect" is conceived in this project in order to enhance the erosion-corrosive wear performance of galvanizing equipment in flowing liquid zinc. This idea comes from the recent finds that the corrosion interface with "orientation-pinning effect" is induced by Fe2B and matrix morphologies of Fe-B alloy during corrosion. The relationships between microtructural factors and interfacial microstructures and erosion-corrosive wear properties in flowing liquid zinc are extensively and systematically investigated by effectively controlling the morphologies and distribution of Fe2B as a corrosion-resistant phase. The key factors and relevant mechanisms during the corrosion process in this situation are deeply discussed because the microstructural morphologies of Fe2B and matrix can affect the corrosion interfacial microstructures and erosion-corrosive wear performance of Fe-B alloy in flowing liquid zinc. It is likely to clarify the effect and its interaction mechanism of corrosion interface with strong "orientation-pinning effect" on erosion-corrosive wear properties of Fe-B alloy in flowing liquid zinc in present research proposed in this project, and it will also put forward an novel idea and an new approach to control the microstructural morphologies and interfacial microstructures of corrosion-resistant materials in flowing liquid zinc, which can improve the erosion-corrosive wear performance of galvanizing components in flowing liquid zinc.

镀锌设备的腐蚀是制约热镀锌工业发展的关键，已成为当前亟待解决的重要课题。耐锌蚀材料中抗蚀相结构形态及腐蚀界面微观结构是决定耐蚀性的两个重要因素，其有效控制是组织设计和大幅提高服役效能的基础。本项目基于Fe-B合金具有基体+Fe2B抗蚀骨架这一独特组织特点，在已澄清其静态腐蚀损伤机制的基础上，着眼于实际损伤是从流动锌液对部件表面微区的冲蚀-磨损损伤这一特征，基于近期发现的Fe2B与基体的组相形态诱发具有"取向钉扎"效应的微观界面，提出有效调控Fe2B与基体形态及强化界面"取向钉扎"效应来提高Fe-B合金抗锌液冲蚀-磨损性能的新思路。通过有效控制抗蚀相Fe2B的定向排列及分布特征，研究组织因素与界面微结构条件及冲蚀-磨损性能之间的关联性；揭示组相形态对界面结构影响的控制因素与机制，阐明强"取向钉扎"效应界面对锌液冲蚀-磨损性能的影响及作用机制，为有效控制组相形态与界面微结构提供新的思路与方法。

镀锌设备的腐蚀是制约热镀锌工业发展的关键，已成为当前亟待解决的重要课题。耐锌蚀材料中抗蚀相结构形态及腐蚀界面微观结构是决定耐蚀性的两个重要因素，其有效控制是组织设计和大幅提高服役效能的基础。本项目基于此思想，采用旋转试样冲蚀的实验方式首先研究了流动锌液对Fe-B合金抗冲蚀性能的影响以及不同参数条件下Fe-B合金的抗冲蚀性能，澄清了冲刷-腐蚀体系中冲刷与腐蚀的交互作用机制；紧接着采用定向凝固手段控制Fe-B合金中Fe2B相的组织尺寸参数和位向关系，研究了界面微观结构的形成及其对冲刷-腐蚀动态损伤过程、Fe-B合金抗冲蚀性能的影响，并探索了腐蚀界面产生“取向钉扎效应”的条件。最后研究了Fe-B合金在流动锌液中的腐蚀-磨损性能及损伤机制，通过合理改变腐蚀与磨损强度澄清了腐蚀与磨损的交互作用机制。主要获得以下结论：.锌液的流动加速了合金溶解和传质过程，冲蚀初期，合金中铁素体的溶解是冲蚀的控制过程；随着冲蚀的进行,控制过程转变为元素在冲蚀产物层中的扩散；冲蚀进入稳定状态后，铁锌化合物和Fe2B骨架形成独特的冲蚀产物层有效弱化了冲刷与腐蚀的交互作用，使得Fe-B合金具有优异抗冲蚀性能。.定向Fe-B合金垂直试样（Fe2B⊥）在流动锌液的冲蚀条件下，铁锌化合物能以合金中的Fe2B为“模板”取向生长，并与Fe2B紧密结合形成“取向钉扎效应”，极大地提高Fe-B合金抗流动锌液冲蚀性能。Fe2B间距能够影响铁锌化合物在流动锌液中的生成和长大，当Fe2B间距较小时，狭小的空间阻碍了铁锌化合物的进一步生长，在流动锌液的作用下易于溶解、清除；当Fe2B间距较大时，过多的铁锌化合物在Fe2B相间隙中形核，导致Fe2B相间的铁锌化合物组织致密性变差，适当的Fe2B间距使Fe2B骨架与铁锌化合物结合最为紧密，具有好的“取向钉扎效应”。.Fe-B合金较316L不锈钢表现出优异的抗锌液腐蚀磨损性能；腐蚀-磨损界面结构依赖于材料内部抗蚀相Fe2B的形态和取向，界面结构的改变会造成腐蚀界面前沿腐蚀产物的生长方式和结构发生变化，影响抗锌液腐蚀-磨损性能；腐蚀-磨损过程中，基体与锌液的腐蚀在界面前沿形成腐蚀产物层、造成Fe2B失去基体支撑、促进磨损。反之，磨损破坏腐蚀产物层、加速Fe2B的碎裂与剥落，促进基体腐蚀。最终腐蚀与磨损产生强烈交互作用，加速材料的损失。