静水压力对超纯Fe腐蚀行为的影响  

Influence of Hydrostatic Pressure on Corrosion Behavior of Ultrapure Fe

作　　者：马荣耀 王长罡[1] 穆鑫[1] 魏欣[1] 赵林[1] 董俊华[1] 柯伟[1] MA Rongyao;WANG Changgang;MU Xin;WEI Xin;ZHAO Lin;DONG Junhua;KE Wei(Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院金属研究所,沈阳110016 [2]中国科学院大学,北京100049

出　　处：《金属学报》2019年第7期859-874,共16页Acta Metallurgica Sinica

基　　金：国家重点研发计划项目No.2017YFB0702302;国家自然科学基金项目Nos.51671200、51501204、51801219~~

摘　　要：采用失重测试、动电位极化和电化学噪声研究了静水压力对超纯Fe在3.5%NaCl中腐蚀行为的影响。利用离散小波分析方法去除噪声信号的直流漂移,然后进行散粒噪声和随机分析;利用Hilbert-Huang变换对噪声信号进行时频分析;用SEM观察腐蚀试样的表面形貌。失重测试和动电位极化的研究结果表明,增大静水压力提高了超纯Fe在3.5%NaCl中的腐蚀速率。电化学噪声分析结果表明,在整个浸泡期间,增大静水压力促进了点蚀的发展,提高了局部腐蚀的倾向。在浸泡初期,超纯Fe以发生局部腐蚀(如点蚀形核、亚稳态点蚀、点蚀)的模式为主,增大静水压力对点蚀形核过程有一定的抑制作用,降低了点蚀孕育速率,但对亚稳态点蚀和稳态点蚀的发展过程有促进作用,提高了点蚀生长概率;随着浸泡时间的延长,其逐渐转为以均匀腐蚀的模式为主,增大静水压力仍然促进亚稳态点蚀和稳态点蚀的发展,提高点蚀生长概率,但是却相对地抑制了均匀腐蚀过程。Hydrostatic pressure is part of the crucial factors affecting deep sea corrosion. At present,there have been a lot of studies on the pitting behavior of metallic materials under hydrostatic pressure,but most of them take passive metallic materials as the research object, and the influence rule of hydrostatic pressure on the pitting behavior of metallic materials also presents diversity. People not only have no clear understanding of its mechanism, but also have some disputes. The generation and growth of pitting corrosion are dependent on the structure of materials, chemical composition and service environment. Inclusion, passivation ability and surface roughness can all affect the pitting behavior of metal materials. Due to the single composition and simple structure of ultrapure Fe, the influence of phase, inclusion and other factors on corrosion behavior under hydrostatic pressure can be avoided, which is more conducive to elucidate the mechanism of hydrostatic pressure on metal corrosion behavior. In addition, the influence of hydrostatic pressure on the corrosion behavior of ultrapure Fe is rarely reported. So, the effect of hydrostatic pressure on the corrosion behavior of ultrapure Fe exposed to 3.5%NaCl aqueous solution is investigated by potentiodynamic polarization curves and electrochemical noise method. The noise signals are analyzed by shot noise theory, stochastic analysis and Hilbert-Huang transform. Besides, the surface morphology of the corrosion sample is observed by SEM. The results of weight loss test and potentiodynamic polarization study show that increasing hydrostatic pressure accelerated the corrosion rate of ultrapure Fe exposed to 3.5%NaCl. The results of electrochemical noise study show that increasing hydrostatic pressure promotes the development of pitting corrosion and increases the tendency of local corrosion throughout the immersion. At the beginning of soaking, local corrosion(such as pitting nucleation, metastable pitting and stable pitting) mainly occurred in ultrapure Fe, incr

关 键 词：静水压力 电化学噪声 散粒噪声理论 随机分析 HILBERT-HUANG变换 

分 类 号：O646.6[理学—物理化学] TG171[理学—化学]