镍-石墨烯复合涂层在高温混合气体中的氧化机理研究

High temperature heat exchanger components are widely used in industrial systems. High temperature oxidation is an important factor that restricts the development of high temperature heat exchanger components. Due to the interaction among oxidation medias coupled with the interaction between oxidation medias and materials, the high temperature oxidation mechanism is complex and needs to be further studied. The nickel-graphene composite coatings are applied in the high temperature gas mixture (oxygen, water vapor, carbon dioxide and nitrogen). The microscopic model of the interaction/reaction between gas mixture and metal interface and the microscopic model of nickel-graphene composite coatings are established. The two models are coupled to form a complex microscopic simulation system of nickel-graphene and high-temperature gas mixture. The microscopic dynamic characteristic is studied that molecular bonds form, crack and exchange among the gas mixture component moleculars and between the gas moleculars and metal atoms. The influences of gas mixture temperature and pressure, graphene ratio and nickel crystal orientation are discussed. The surface morphology and oxidative corrosion weight gain of the coatings are tested by high temperature oxidation test of the coatings, which verifies the results of the molecular dynamics simulation qualitatively. The high temperature oxidation mechanism of nickel-graphene composite coatings in gas mixture is obtained through the combination of molecular dynamics simulation and experiment, which provides theoretical guidance for the development and optimization of coatings against high temperature corrosion.

高温换热部件被广泛应用于工业系统中，高温氧化是制约其发展的一项重要因素。由于氧化介质之间和介质与材料之间相互影响，造成高温氧化机理复杂，需要对其进行深入研究。本项目提出将镍-石墨烯复合涂层应用于高温混合气体（氧气、水蒸气、二氧化碳、氮气）中，采用分子动力学模拟与实验测试相结合的方法，建立混合气体与金属界面结合/反应微观模型和镍-石墨烯复合涂层微观界面模型，以及两种模型耦合形成镍-石墨烯与高温混合气体的复杂微观模拟体系，协同考虑组分含量、温度和压力以及石墨烯配比和镍晶体取向等多种影响因素，研究高温混合气体各组分分子间及气体分子与金属原子间离子键形成、裂化和互换的微观动态特性。通过涂层高温氧化实验，测试涂层表面形貌和氧化腐蚀增重，定性验证分子动力学模拟结果，共同揭示镍-石墨烯复合涂层在高温混合气体中的氧化微观机理。项目研究成果将为有效防治换热部件高温氧化的涂层研发及优化技术提供理论指导。

高温换热部件被广泛应用于工业系统中，高温氧化是制约其发展的一项重要因素。由于氧化介质之间和介质与材料之间相互影响，造成高温氧化机理复杂，需要对其进行深入研究。本项目采用实验测试与分子动力学相结合的方法，研究了镍-石墨烯复合涂层在高温混合气体（氧气、水蒸气、二氧化碳、氮气）中的氧化机理。主要完成了基于310S不锈钢的镍-石墨烯复合涂层制备和优化，通过优化关键影响因素获得最优制备工艺；实验研究了镍-石墨烯复合涂层在高温混合气体中氧化特性，对比分析了涂层性质、氧化温度和氧化时间等因素对涂层抗氧化特性的影响；采用分子动力学研究了镍在高温高压环境中的微观反应进程，建立了高温氧气与镍界面结合和反应微观模型，并分析了晶体方向、温度、压力和电场强度等因素对界面处镍氧结合和反应的影响规律。研究结果揭示了镍-石墨烯复合涂层在高温混合气体中的氧化机理，为有效防治换热部件高温氧化的涂层研发及优化技术提供理论指导。项目资助共完成学术论文7篇，其中SCI论文5篇，EI论文1篇，培养硕士研究生4名，申请发明专利1项。项目共投入直接研究经费24万元，已支出12.6124万元，剩余11.3876万余，计划用于后续的研究支出。