高温影响下化工设备钛合金的电化学腐蚀机制  

Electrochemical corrosion mechanism of titanium alloy in chemical equipment under influence of high temperature

作　　者：王静虹 孟庆龙 王仓天 支有冉[3] WANG Jinghong;MENG Qinglong;WANG Cangtian;ZHI Youran(College of Safety Science and Engineering,Nanjing Tech University,Nanjing Jiangsu 211816,China;Sobute New Materials Co.,Ltd.,Nanjing Jiangsu 211103,China;College of Mechanical Engineering,Nanjing Institute of Technology,Nanjing Jiangsu 210009,China)

机构地区：[1]南京工业大学安全科学与工程学院,江苏南京211816 [2]江苏苏博特新材料股份有限公司,江苏南京211103 [3]南京工程学院机械工程学院,江苏南京210009

出　　处：《中国安全科学学报》2021年第1期95-101,共7页China Safety Science Journal

基　　金：国家自然科学基金资助(51606092,21406115)。

摘　　要：为预防化工用钛设备在遭遇火灾等高温影响后由于耐蚀性下降而导致的设备腐蚀失效事故,利用电化学试验技术,通过极化曲线与电化学阻抗谱(EIS)研究化工设备钛合金Ti-6Al-4V(TC4)在高温处理后叠加空冷与水冷后的腐蚀行为特征,并构建相应的电化学腐蚀模型,利用该模型探究EIS特征与孔洞深度之间的关系。研究结果表明:高温处理后经空冷与水冷的TC4试样分别在1050和910℃下的腐蚀电流密度最低,且水冷更低于空冷,即在接近相变点温度(约1000℃)附近,水冷相较于空冷可使TC4获得更好的抗腐蚀能力,故钛设备过火后水冷是更好的冷却措施;EIS特征与孔洞深度之间的关系可较为准确地反映TC4的腐蚀情况。In order to prevent corrosion accidents of equipment due to decrease in corrosion resistance of titanium materials after suffering from high temperature of a fire in chemical industry,corrosion behavior characteristics of titanium alloy TC4 after being treated by high temperature and different cooling methods,i.e.,air cooling and water cooling,were studied through polarization curve and electrochemical impedance spectroscopy(EIS)by using electrochemical test technology.Then,a corresponding electrochemical corrosion model was constructed to explore relationship between characteristics of EIS and pore depth.The results show that TC4 sample can obtain the lowest corrosion current density after air cooling and water cooling treatment respectively at 1050 and 910℃with that of water cooling lower than air cooling.This means that when heating temperature is close to phase transition point temperature(about 1000℃)of TC4,water cooling can make samples more resistant to corrosion than the other.Therefore,it proves to be a better cooling measure after titanium equipment is exposed to fire.In addition,based on results of scanning electron microscope,it is found that relationship between EIS characteristics and hole depth could reflect corrosion of TC4 more accurately.So the proposed model provides a theoretical basis for corrosion severity evaluation of titanium alloy equipment.

关 键 词：高温热处理 化工设备 钛合金 Ti-6Al-4V(TC4) 电化学腐蚀 冷却方式 

分 类 号：X937[环境科学与工程—安全科学]