Abstract Distillation column is a fundamental device for the production of the semiconductor polysilicon. Therefore, investigating corrosion leakage protection of the distillation column is of great significance because of the undetectable yet very significant consequences of corrosion leakage to the column. In this work, corrosion investigation of a polycrystalline silicon rectification tower is presented. The composition and crack morphology of the distillation column (316 L austenitic stainless steel) were detected and analysed using component and hardness analysers. The effects of pH and temperature on the corrosion rate were studied by conducting electrochemical experiments. According to the macroscopic test results, the surface of the tower was covered with a large number of pits and cracks of different depths. Furthermore, based on the metallographic analysis, SEM analysis, and energy spectrum analysis results, it was determined that the crack morphology was mostly intergranular and transgranular. Combined with the test data and process environment, it has been determined that the main forms of corrosion for rectification towers are pitting corrosion and stress corrosion caused by chloride ions. According to the results of electrochemical experiments, the corrosion rate of 316 L stainless steel is negatively correlated with pH value for a pH range of 4–6 at constant temperatures. However, the corrosion rate is positively correlated with temperature for the range of 60 °C–90 °C at constant pH values. From the analysis of the corrosion morphology, the corrosion failure mode of 316 L stainless steel is largely attributed to pitting corrosion when the column is operated at low temperatures (60 °C and 70 °C). However, at high temperatures (90 °C), a transformation from pitting corrosion to stress corrosion occurs along the crystalline form. To ensure the stable operation of the polysilicon rectification tower, this paper proposes corrosion protection measures based on the results of the analysis as described.

中文翻译：

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半导体多晶精馏塔腐蚀失效分析

摘要 蒸馏塔是生产半导体多晶硅的基本设备。因此，研究蒸馏塔的腐蚀泄漏保护具有重要意义，因为腐蚀泄漏到塔中的后果不可检测但非常显着。在这项工作中，介绍了多晶硅精馏塔的腐蚀研究。使用成分和硬度分析仪检测和分析蒸馏塔（316 L 奥氏体不锈钢）的成分和裂纹形态。通过电化学实验研究了pH和温度对腐蚀速率的影响。根据宏观测试结果，塔身表面布满了大量不同深度的凹坑和裂缝。此外，根据金相分析、SEM分析和能谱分析结果，确定裂纹形态多为晶间和穿晶。结合试验数据和工艺环境，确定精馏塔腐蚀的主要形式是点蚀和氯离子引起的应力腐蚀。根据电化学实验结果，316 L 不锈钢的腐蚀速率与 pH 值在恒定温度下的 4-6 范围内呈负相关。然而，在恒定 pH 值下，腐蚀速率与 60 °C–90 °C 范围内的温度呈正相关。从腐蚀形貌分析，316 L 不锈钢的腐蚀失效模式主要归因于色谱柱在低温（60 °C 和 70 °C）下运行时的点蚀。然而，在高温 (90 °C) 下，沿晶形发生从点蚀到应力腐蚀的转变。为保证多晶硅精馏塔的稳定运行，本文根据上述分析结果提出腐蚀防护措施。