单相流冲刷条件下一种低合金高强钢的腐蚀行为研究

Erosion-corrosion Behavior of a High Strength Low Alloy Steel in Flowing 3.5%NaCl Solution

通过腐蚀失重、电化学阻抗谱、动电位极化曲线等测试方法,结合腐蚀形貌宏观/微观表征及Raman光谱等手段,系统研究了一种新研制低合金高强钢在单相流冲刷条件下的腐蚀行为。结果表明,低合金高强钢在单相流冲刷条件下的腐蚀失重是静态浸泡条件下的10倍以上;静态浸泡和动态冲刷条件下,低合金高强钢的腐蚀失效均可分为3个不同的阶段,在静态浸泡条件下的性能恶化主要体现在第2和第3阶段,而在动态冲刷条件下耐蚀性能会在第一阶段迅速降低。单向流冲刷阻碍了稳定性腐蚀产物α-FeOOH的生成,从而加速O_(2)、Cl^(-)等的传质以及破坏钝化膜和腐蚀产物膜完整性,最终导致加速腐蚀。

Erosion corrosion behavior of a newly developed high strength low alloy(HSLA)steel in flowing 3.5%NaCl solution was systematically investigated via a home-made rotating erosion device,mass loss measurement,electrochemical impedance spectroscopy and potentiodynamic polarization curve measurement,as well as macroscopic/microscopic characterization of corrosion morphology and Raman spectroscopy.The results revealed that the mass loss of the HSLA steel in flowing 3.5%NaCl so-lution exceeded that in static immersion test by over 10 times.Failure of the HSLA steel in both static immersion and dynamic erosion conditions exhibited three distinct stages.Degradation of the HSLA steel in static immersion conditions primarily manifested in the second and third stages.In contrast,the corrosion resistance of the HSLA steel in dynamic erosion conditions rapidly declined in the first stage.Flow erosion may hinder the formation of a stable corrosion product scale ofα-FeOOH.The relevant accelerating corrosion mechanism may primarily be ascribed to the following two aspects:accelerating the mass transfer of O_(2),Cl^(-)and other species,and compromising the passivation film as well as the integrity of the corrosion product film.