Plate heat exchangers are widespread type of equipment that suffers from pitting corrosion in chloride containing solutions. Anodic behaviour of AISI 316 stainless steel was tested in 3.5% NaCl solution in conditions of ultrasound vibration (27 kHz, 10 W). The potentiodynamic sweep, potentiostatic technique, and galvanostatic technique were used coupled with surface morphology investigation after polarization. The pitting potential increased from 0.26 ± 0.02 V/SSCE to 0.42 ± 0.05 V/SSCE, and repassivation potential increased from 0.03 ± 0.01 V/SSCE to 0.18 ± 0.04 V/SSCE when vibration was applied. The anodic current at applied potential in pitting region was two orders of magnitude lower in conditions of ultrasound vibration. A possible mechanism of vibration influence on pitting is proposed, which is the elimination of pit covers from the vibrating surface, vibration-induced electrolyte motion in and out of the pits, and repassivation of active metal inside the pits.

中文翻译：

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超声振动条件下AISI 316不锈钢板的点蚀抑制

板式换热器是一种广泛使用的设备，在含氯化物的溶液中会出现点蚀。在3.5％NaCl溶液中，在超声振动（27 kHz，10 W）的条件下，对AISI 316不锈钢的阳极行为进行了测试。极化后使用了电位动力学扫描，恒电位技术和恒电流技术以及表面形态研究。当施加振动时，点蚀电位从0.26±0.02 V / SSCE增加到0.42±0.05 V / SSCE，重钝化电位从0.03±0.01 V / SSCE增加到0.18±0.04 V / SSCE。在超声振动条件下，点蚀区域中施加电势的阳极电流要低两个数量级。提出了振动对点蚀的可能影响机理，