耐候钢锈层在大气环境中的防护机制及其稳定化处理技术

Protective Mechanism of Weathering Steel Rust Layer in Atmospheric Environment and Its Stabilization Treatment Technology

  • 摘要: 耐候钢能够自发形成具有防护作用的锈层。稳定致密且贴附表面的锈层能够有效地阻碍腐蚀介质与基体的接触,可在自然环境中发挥优异的耐腐蚀性。本文从锈层内外结构、锈层成分和形成机制等方面对耐候钢的锈层保护性能进行了阐述,详细分析了合金化元素、环境因素(盐度、温度、湿度、辐照等)对保护性锈层形成和稳定化的影响机制,但复杂大气环境(如海洋-工业大气复合环境)对锈层形成的作用机制、多种合金元素共存的负面影响等方面的研究存在明显不足。此外,由于完整稳定锈层的形成条件苛刻,在恶劣环境中甚至难以形成保护性锈层,本文详细讨论了现有的锈层稳定化处理技术,对提升耐候钢的可靠性、稳定性和适用性具有重要意义,高效环保的锈层稳定化处理技术将是未来重要的发展方向之一。

     

    Abstract: Corrosion is a major form of steel loss, which results in material thinning, perforation, and stress concentration, triggering deterioration of mechanical properties, ultimately causing failure of the engineering structure and safety accidents. Weathering steels are widely used in various fields (e.g. bridges, buildings, and vehicles) and are recognized as economical and environment-friendly steel materials. Protective rust layers can spontaneously form on weathering steels. Stable, compact and adhesive rust layers can effectively inhibit the contact between corrosive media and steel substrate, which exerts superior corrosion resistance in natural environment. With the increase of exposure time length, the corrosion resistance of the weathering steel rust layer becomes more evident. This paper elaborated the protective mechanisms of weathering steel rust layer from the aspects of inner/outer structure, the composition and the formation mechanism of rust layers. The effects of alloying elements and environmental factors (salinity, temperature, humidity, and irradiation) on the formation and stabilization of protective rust layers have been discussed in details. However, there is still a lack of study on the protective rust layers especially on the effect of complicated atmospheric environment (e.g. marine-industrial complex environment), the negative effect of the co-existence of multi alloying elements. Besides, the forming condition of integral and stable rust layers is strict, and the protective rust layers even cannot form in harsh environments. To resolve problems that may exist before stabilization of the rust layer and to ensure the stable formation of the rust layer on the weathering steels, it is still recommended to take appropriate protective measures. This paper also particularly discussed the available rust stabilization treatment technology, which is highly important for improving the reliability, stability and applicability of weathering steels. The development of efficient and environment-friendly rust stabilization treatment technology would be an important research area in the future.

     

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