非晶合金涂层的结构调制及其对涂层冲击韧性的影响研究

The amorphous alloy coating of excellent corrosion and wear resistance is one kind of the most important surface protected materials,showing great potential in many industry applications such as ocean development and petrochemical. However,under the impact loading,cracks are easily initiated in the amorphous coatings and subsequently coating/substrate debonding occurs, which will affect siginificantly the performance and lifetime of the coating.Up to now,study concerning on how to improve the impact toughness of the amorphous alloy coating is very lacking.In this project,a newly degsigned multilayered composite coating systems containing Fe-based amorphous layers and tough NiCrAl layers will be chosen as the research object. The research contents include: (1)Designing and fabrication of the multilayered amorphous composite coatings; (2)Analyzing the features of interfacial structure between two kinds of layers and each component as well as their effects on the mechanical properties of the coatings; (3)Study on the failure behavior and mechansim for the amorphous composite coatings under impact loading. The present project can enhance the understanding of interfacial structure features in the multilayered coatings and their factors, as well as the micro-mechanism for the effect of the interfacial structure features on the mechanical properties of the coatings. On the other hand, this project is also of an important significance for the manufacture of amorphous composite coatings with high impact toughness, and for their practial application in various industrial fields.

非晶合金涂层其优异的防腐耐磨性能，使其成为最重要的表面防护材料之一，在海洋开发、石油化工等工业领域有广阔的应用前景。然而，非晶合金涂层在冲击载荷条件下易产生微裂纹并引起与基体剥离，极大地影响了其使用性能与服役寿命。目前，国内外针对改善非晶合金涂层冲击韧性的研究十分欠缺。本项目拟以Fe基非晶合金涂层/NiCrAl晶态层复合形成的多层调制结构涂层为研究对象,重点研究：（1）多层调制结构非晶基复合涂层的设计与制备；（2）非晶/晶态层界面结构及组元材料对涂层力学性能的影响规律及机制；（3）冲击载荷作用下多层调制涂层的失效行为及机理。通过上述研究，弄清楚非晶/晶态层之间界面结构特征及影响因素，揭示异质层界面结构对涂层力学性能的影响规律及机制。本项目的研究将对制备高冲击韧性非晶基复合涂层，促进其在工业各领域的应用具有重要的科学意义和应用价值。

Fe基非晶涂层较差的抗冲击性能已成为当前阻碍非晶涂层工程应用最核心的问题之一。本项目提出多种结构调控方法来改善其冲击韧性，并对界面结构特征以及涂层的冲击破坏与韧化行为进行了系统研究。主要成果如下：（1）开发出高结合力、抗冲击的Fe基非晶/NiCrAl多层调制结构涂层。其界面结构特征如下：两相完全浸润、存在成分梯度、致密且局部冶金结合。多层结构中层数越多，则涂层冲击性能越好。多层结构的韧化机制为NiCrAl层的能量吸收以及多层结构降低冲击过程中的应力集中。（2）开发出高结合力、韧性较好的316L不锈钢颗粒强化非晶复合涂层。确定了不锈钢增强相的最优添加量约为8 vol%。研究发现韧性不锈钢相能阻碍裂纹扩展，因而在拉伸或弯曲载荷作用下，提高非晶涂层界面结合强度以及断裂功。（3）开发出抗冲击Al2O3颗粒强化Fe基非晶涂层。发现陶瓷增强相能在不影响耐蚀性前提下提高非晶涂层冲击韧性。Al2O3/非晶的界面结构不存在成分梯度与冶金结合。研究发现其增韧机制主要是硬质陶瓷相对主裂纹的偏析以及降低冲击过程的应力集中，以及陶瓷相自身的微裂纹增韧。（4）重新认识了界面结构对非晶复合涂层腐蚀行为的影响机制。金属韧性相以及界面的引入通常被认为会产生电偶效应而恶化涂层腐蚀性能。发现不锈钢相与非晶基体界面处是点蚀起源位置，但两者之间仅存在微弱的电偶效应。不锈钢/非晶涂层腐蚀性能降低的本质来源于不锈钢粉末在热喷涂过程的表面氧化所形成的不稳定的Fe3O4纳米晶。这一结果首次提出将增强相抗氧化性能用于今后高性能非晶复合涂层的设计中。截止目前，相关研究成果已经在Acta Materialia、Electrochimica Acta等期刊上发表SCI收录论文9篇，参加学术会议3次，申请发明专利4项，其中已授权2项，培养硕士生3人。项目研究对涂层界面调控、高冲击韧性涂层体系设计有重要的指导意义与应用价值。