杨志勇,李明哲,郝义磊,刘凯俐,司慧玲,刘冬梅.黄铜晶间腐蚀机理的实验及模拟研究[J].表面技术,2018,47(8):244-250.
YANG Zhi-yong,LI Ming-zhe,HAO Yi-lei,LIU Kai-li,SI Hui-ling,LIU Dong-mei.Experimental and Simulation Study on Intergranular Corrosion Mechanism of Brass[J].Surface Technology,2018,47(8):244-250 |
| 黄铜晶间腐蚀机理的实验及模拟研究 |
| Experimental and Simulation Study on Intergranular Corrosion Mechanism of Brass |
| 投稿时间：2018-03-24 修订日期：2018-08-20 |
| DOI：10.16490/j.cnki.issn.1001-3660.2018.08.033 |
| 中文关键词: 黄铜 晶间腐蚀 电化学法 第一性原理 |
| 英文关键词:brass intergranular corrosion electrochemical method first principles |
| 基金项目: |
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| Author | Institution |
| YANG Zhi-yong | 1.Sinopec Northwest Oilfield Branch, Urumchi 830011, China |
| LI Ming-zhe | 2.Department of Electronic Information Engineering, School of Electronic Information Engineering, Tianjin University, Tianjin 300072, China |
| HAO Yi-lei | 3.Faculty of Science, China University of Petroleum (East China), Qingdao 266580, China |
| LIU Kai-li | 3.Faculty of Science, China University of Petroleum (East China), Qingdao 266580, China |
| SI Hui-ling | 3.Faculty of Science, China University of Petroleum (East China), Qingdao 266580, China |
| LIU Dong-mei | 1.Sinopec Northwest Oilfield Branch, Urumchi 830011, China |
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| 中文摘要: |
| 目的 为了探究黄铜在含氨介质中的晶间腐蚀加速试验方法，明确黄铜中 Zn 含量对晶间腐蚀敏感性的影响规律和机理。方法 采用电化学方法加速实现了黄铜表面的晶间腐蚀过程，利用 XRD 和金相显微镜分析腐蚀产物及表面形貌，对比分析 H70 和 H80 黄铜的晶间腐蚀规律。使用 Materials Studio 中的 DMol3 模块模拟 NH4 +和 NH3在 H70 和 H80 黄铜晶界表面的吸附和反应过程，对比腐蚀粒子在黄铜表面的吸附规律和反应能垒，揭示黄铜晶间腐蚀敏感性的机理。结果 试验结果表明，在 NH4Cl 溶液中，以 100 倍自腐蚀电流密度恒电流处理的黄铜，在 4 h 内能够发生明显的晶间腐蚀。黄铜晶间腐蚀的产物主要为铜氨络合物和锌氨络合物，H70 黄铜的晶间腐蚀敏感性大于 H80 黄铜。模拟研究表明，NH4Cl 溶液中的 NH4 +会优先在黄铜表面的晶界处发生物理吸附，随后 NH4 +跨越 1.15 eV（H70）和 1.17 eV（H80）反应能垒分解为 NH3和H+，其中 NH3优先吸附于晶界中偏析的 Zn 原子顶位形成络合物，其次与晶界的 Cu 形成络合物，H70 晶界中的 Zn 含量更高，因此 H70 的晶间腐蚀敏感性更强。结论 通过电化学恒电流处理法将黄铜的晶间腐蚀发生时间从 7 d 减少到 4 h，并通过量子化学计算和腐蚀产物分析确定了黄铜在 NH4Cl 溶液中发生晶间腐蚀的机理。 |
| 英文摘要: |
| The work aims to explore intergranular corrosion accelerated testing method of brass in ammoniated medium, and clarify law and mechanism of influence of Zn content on brass intergranular corrosion susceptibility. During the experiment, intergranular corrosion process of brass surface was accelerated in electrochemical method, then corrosion products and surface morphology were analyzed by XRD and metallographic microscope, and intergranular corrosion rules of brass H70 and H80 were comparatively analyzed. During the simulation, adsorption and reaction process NH4 +/NH3 on the surface of H70/H80 grain boundaries were simulated by using DMol3 module in Materials Studio. Adsorption law and reaction energy barrier of corrosion particles on brass surface were compared to reveal the mechanism of intergranular corrosion susceptibility of brass. Experimental study showed that, in the NH4Cl solution, obvious intergranular corrosion could happen in 4 hours to the brass treated at 100 times self-corrosion current density. Main products of intergranular corrosion were [Cu(NH3)4]Cl2 and [Cu(NH3)4]Cl2, and intergranular corrosion susceptibility of brass H70 was higher than that of H80. Simulation study showed that physical adsorption of NH4 + in the NH4Cl solution would preferentially occur on the grain boundary, then NH4 + was decomposed into NH3 and H+ beyond reactive barrier of 1.15 eV (H70) and 1.17 eV (H80), respectively. NH3 was preferentially adsorbed on Zn atom being segregated on the grain boundary to form a complex, then it formed a complex with Cu on grain boundary. The Zn content on H70 grain boundary was higher than that on H80 grain boundary, thus brass H70 had higher intergranular corrosion susceptibility. This work cuts intergranular corrosion time of brass in NH4Cl solution solution from 7 days to 4 hours in electrochemical galvanostatic method. Besides, intergranular corrosion mechanisms of brass are clarified based upon quantum chemistry calculation and corrosion products analysis. |
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