金属氮化物涂层提升N80管线钢阻氢性能与机理研究

Study on the hydrogen permeation resistance and protective mechanism of N80 pipeline steel coated with metal nitride coatings

  • 摘要: 【目的】为解决N80管线钢在氢气储运等环境下面临的氢脆风险,在金属材料表面制备阻氢涂层是解决金属材料氢渗透和氢损脆的重要手段之一,亟需开发高效的阻氢防护涂层。然而,目前缺少在统一标准下对不同代次氮化物涂层进行系统性的性能对比,且涂层的“结构-性能”内在关联机制尚不明确。因此,本研究旨在通过对比TiN、AlCrN与(TiAlCrSiY)N三种涂层的综合防护性能,探究其防护机理,为临氢环境下的涂层选材与设计提供科学依据。【方法】采用多弧离子镀技术在N80钢基体上制备了三种氮化物涂层。利用扫描电镜(SEM)、数码显微镜、显微硬度计和微米划痕仪对涂层的微观结构与力学性能进行表征。通过电化学极化曲线测试评估其耐腐蚀性。采用Devanathan-Stachurski双电解池,在电化学监测的液相和气相两种充氢模式下,系统评价各涂层的阻氢渗透性能。【结果】AlCrN涂层表现出最佳的综合性能,其表面最致密平整、缺陷最少,并展现出最高的硬度和最强的结合力。(TiAlCrSiY)N涂层虽因多元素协同效应而耐腐蚀性最优,但其存在较多表面团聚颗粒与微观缺陷,结合力在三种涂层中最差。关键的阻氢渗透性能测试表明,无论液相还是气相充氢,AlCrN涂层均表现出最佳的阻氢效果,与N80基材相比,有效扩散系数降低了83.68%,在气相和液相条件下阻氢效率分别高达99.23%和84.76%。测试结果表明,涂层的阻氢效率与其微观结构致密性高度相关。【结论】综合评估认为,三种金属氮化物涂层,不仅有良好的阻氢效果,而且耐腐蚀性和界面结合性等综合性能优良。涂层微观结构的致密性是决定其阻氢性能的首要因素,AlCrN涂层有着最致密的微观结构、均衡的力学性能和最优的阻氢效率,是三种涂层中最适用于氢气环境的防护方案。未来阻氢涂层开发过程中应优先通过工艺优化来获得低缺陷的致密结构,其次进行成分优化增强化学稳定性,同步提升其耐腐蚀特性和机械性能,这对于保障氢能储运设施安全具有重要的工程指导意义。

     

    Abstract: Objective To address the risk of hydrogen embrittlement facing N80 pipeline steel in environments like hydrogen storage and transportation, the development of effective hydrogen permeation barrier coatings has become a crucial approach. However, a systematic, standardized comparison across successive generations of nitride coatings is still lacking, and the intrinsic structure–property correlation governing their hydrogen permeation resistance remains unclear. Therefore, this study comparatively evaluates the comprehensive protective performance of TiN, AlCrN, and (TiAlCrSiY)N coatings, elucidating their hydrogen barrier mechanisms to inform coating selection and design for hydrogen service environments. Methods Three types of nitride coatings were prepared on N80 steel substrates using multi-arc ion plating technology. The microstructure and mechanical properties of the coatings were characterized by scanning electron microscopy (SEM), digital microscopy, microhardness testing, and micro-scratch testing. Their corrosion resistance was evaluated via electrochemical polarization curves. A Devanathan-Stachurski dual electrochemical cell was employed to systematically evaluate the hydrogen permeation resistance of each coating under two distinct hydrogen charging modes: electrochemical (liquid-phase) and gaseous (gas-phase). Results The AlCrN coating exhibited the best overall performance, featuring the densest, flattest surface with the fewest defects, and it demonstrated the highest hardness and the strongest adhesion. Although the (TiAlCrSiY)N coating showed optimal corrosion resistance due to the synergistic effect of its multiple elements, it suffered from numerous surface agglomerates and micro-defects, resulting in the weakest adhesion among the three. Hydrogen permeation tests revealed that, regardless of the charging mode, the AlCrN coating provided the most effective barrier against hydrogen. Compared to the bare N80 substrate, it reduced the effective diffusion coefficient by 83.68%, with hydrogen blocking efficiencies reaching as high as 99.23% (gas-phase) and 84.76% (liquid-phase). The results clearly indicate a strong correlation between the hydrogen blocking efficiency of the coatings and their microstructural density. Conclusion A comprehensive evaluation confirms that all three nitride coatings provide good hydrogen resistance and other beneficial properties like corrosion resistance and adhesion. The microstructural density of the coatings is the primary factor determining their hydrogen permeation resistance. The AlCrN coating, with its superior microstructural density, balanced mechanical properties, and optimal hydrogen blocking efficiency, represents the most suitable protective solution for hydrogen service among the three options. Future development of hydrogen barrier coatings should prioritize process optimization to achieve low-defect, dense microstructures, followed by compositional optimization to enhance chemical stability and mechanical properties. This approach holds significant engineering guidance for ensuring the safety of hydrogen energy infrastructure.

     

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