吴广春,李德明,张梦梦.交流电对X80钢腐蚀行为影响研究[J].表面技术,2022,51(6):307-316.
WU Guang-chun,LI De-ming,ZHANG Meng-meng.Alternating Current on Corrosion Behavior of X80 Steel[J].Surface Technology,2022,51(6):307-316 |
| 交流电对X80钢腐蚀行为影响研究 |
| Alternating Current on Corrosion Behavior of X80 Steel |
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| DOI：10.16490/j.cnki.issn.1001-3660.2022.06.029 |
| 中文关键词: X80钢 交流电流密度 腐蚀行为 阴极保护 |
| 英文关键词:X80 steel AC current density corrosion behavior CP |
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| 中文摘要: |
| 目的 明确交流电对X80钢的腐蚀电化学动力学参数、腐蚀发展历程和腐蚀速率的影响规律。方法 利用交流电流密度作用下X80钢试样的动电位极化测试，分析交流电对X80钢腐蚀电化学动力学参数的影响。搭建室内腐蚀质量损失模拟试验，并对试验过程中试样的阴极保护和交流干扰参数进行监测，分析交流电对X80钢试样腐蚀速率、扩散电阻和直流电流密度的影响规律。利用拉曼光谱测试和微观形貌相结合的方法，对交流电作用下X80钢试样的腐蚀形貌和腐蚀产物成分变化过程进行分析。结果 交流电使X80钢的自腐蚀电位负向偏移，交流电流密度小于100 A/m2时，负移幅度随交流电流密度的增加而明显增大;交流电流密度大于100 A/m2时，腐蚀电位则整体接近。自腐蚀电流密度呈现同样的规律，阴极和阳极塔菲尔斜率无明显变化。试样极化电位从–0.428 V(vs. SCE)负移至–0.928 V时，面积为6.5、1.0 cm2试样的扩散电阻分别从约0.063、0.048 Ω.m2减小至0.051、0.036 Ω.m2。交流电流密度从0增大到300 A/m2，极化电位–0.428、–0.878、–0.928 V对应的直流电流密度平均值的变化系数分别为0.83、1.72、2.30。交流电加速了X80的腐蚀，交流电流电流密度从0 A/m2增大到300 A/m2时，腐蚀速率增幅呈现先显著后平缓的规律，腐蚀形貌由均匀腐蚀→点腐蚀→局部腐蚀转变，交流电流密度达到200、300 A/m2时，试样的腐蚀产物中出现了γ-FeOOH。结论 交流电促进了X80钢的阴阳极反应过程，且对阳极反应过程的影响大于对阴极，X80钢自腐蚀电位出现负向偏移，自腐蚀电流密度增大。交流电加速了离子传质过程，表现为阴极极化下试样扩散电阻变小，同时增大了阴极保护所需的电流密度。交流电改变了X80钢的腐蚀形貌，随着交流电流密度的增大，腐蚀形貌由均匀腐蚀→点腐蚀→局部腐蚀转变。高的交流电流密度下，腐蚀产物中出现的γ-FeOOH为强氧化剂，进一步加速了腐蚀。 |
| 英文摘要: |
| This paper aims to clarify the influence of alternating current on the electrochemical kinetic parameters of corrosion process, corrosion development and corrosion rate of X80 steel. The influence of AC on the electrochemical kinetic parameters of X80 steel corrosion was analyzed by using the dynamic potential polarization test of X80 steel specimens under the action of AC current density; The indoor corrosion weightlessness simulation test was built and the cathodic protection and AC interference parameters of the specimens were monitored during the test to analyze the influence of AC on the corrosion rate, diffusion resistance and DC current density of X80 steel specimens; The corrosion morphology and the change process of corrosion product composition of X80 steel specimens under the action of AC were analyzed by using the combination of Raman spectroscopy test and microscopic morphology. The results show that the A.C. negatives the free-corrosion potential of X80, when the AC current density is less than 100 A/m2, the negative shift amplitude increases significantly with the increasement of the AC current density, and when the AC current density is greater than 100 A/m2, the corrosion potential is close to each other. The free-corrosion current density shows the same rule as the free-corrosion potential, and no significant change in the slope of the cathode and anode Tafel. When the polarization potential of the X80 steel sample is negatively shifted from –0.428 V (vs. SCE) to –0.928 V, the diffusion resistance of the sample with the surface area of 6.5 cm2 and 1.0 cm2 decreases from 0.063, 0.048 Ω.m2 to 0.051, 0.036 Ω.m2. When the alternating current density increases from 0 to 300 A/m2, the average DC current density corresponding to the polarization potentials of –0.428, –0.878 and –0.928 V increased 0.83, 1.72 and 2.30 times, respectively. The alternating current accelerated the corrosion of X80. When the alternating current density increased from 0 A/m2 to 300 A/m2, the corrosion rate increased significantly and then slowly. The corrosion morphology shows that as the AC current density increased, the corrosion morphology changes from uniform corrosion to pitting corrosion and finally to local corrosion. When the AC current density reaches 200 and 300 A/m2, γ-FeOOH appears in the corrosion products of the specimens. These results show that AC promoted the cathode and anode reaction process of X80 steel, and had a greater impact on the anode reaction process. The AC result in a negative shift to X80 free-corrosion potential and increased the free-corrosion current density. The AC accelerated the mass transfer process of ions, which is manifested by the decrease of the diffusion resistance under cathodic polarization. Also, the AC changed the development morphology of corrosion, with the corrosion morphology changed from uniform corrosion to pitting corrosion and finally localized corrosion. At high AC current density, a strong oxidant γ-FeOOH appears in the corrosion products, which accelerates the corrosion further. |
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