TA2-B10管不同电偶腐蚀防护方式对B10管腐蚀特性的影响

为研究TA2-B10合金管在不同电偶腐蚀防护方式下对B10管腐蚀特性的影响，在青岛小麦岛海水试验场设置TA2-B10管直接连接、电绝缘连接、电绝缘＋涂层连接三组不同电偶腐蚀防护方式对照管道，依次进行1m/s、3m/s、4m/s流动海水与浸泡交替腐蚀试验。对试验后的三组B10管道线切割，通过管道内表面电位分布试验分析不同电偶腐蚀防护方式下B10管道的腐蚀类型；采用动电位极化曲线、电化学阻抗谱和微观表征，分析不同电偶腐蚀防护方式下距离法兰接头250mm处B10管试样的腐蚀特性。结果表明，直接连接TA2-B10管处于电偶腐蚀状态，B10端内电位正移腐蚀加速，电绝缘连接和绝缘＋涂层连接TA2-B10管均处于自腐蚀状态，但电绝缘＋涂层连接具有更好的绝缘效果；电绝缘＋涂层连接防护下的B10试样，腐蚀电流密度最小，自腐蚀电位最负；三组B10试样阻抗谱均呈现单容抗弧特征，电绝缘＋涂层连接防护下的B10试样具有更大的传递电阻和膜层电阻；电绝缘＋涂层连接能有效减缓点蚀、坑蚀和晶间腐蚀三种腐蚀倾向。以上结果综合说明，绝缘＋涂层防护方式具有更好的电偶腐蚀防护效果。

Influence of different galvanic corrosion protection methods of TA2-B10 pipe on the corrosion characteristics of B10 pipe

In order to study the influence of TA2-B10 alloy tube on the corrosion characteristics of B10 tube under different galvanic corrosion protection methods. At the Qingdao Xiaomaidao Sea Water Test Site, three sets of TA2-B10 pipelines with different galvanic corrosion protection methods are set up with direct connection, electrical insulation connection, and electrical insulation+coating connection. Then carry out 1m/s, 3m/s, 4m/s flowing seawater and immersion alternate corrosion tests in sequence. Cut the three sets of B10 pipe lines after the test. Through the pipeline inner surface potential distribution test, analyze the corrosion type of the B10 pipeline under different galvanic corrosion protection methods; use the potential polarization curve, electrochemical impedance spectroscopy and microscopic characterization to analyze the corrosion characteristics of the B10 at a distance of 250 mm from the flange joint under different galvanic corrosion protection methods. The results show that the directly connected TA2-B10 tube is in a galvanic corrosion state, the potential in the B10 terminal is positively shifted and the corrosion is accelerated, and the electrical insulation connection and the insulation+coating connection TA2-B10 tube are in a self-corrosive state, but the electrical insulation+coating connection has better insulation effect; the B10 sample under electrical insulation+coating connection protection has the smallest corrosion current density and the most negative self-corrosion potential; the impedance spectra of the three groups of B10 samples all show the characteristics of single capacitive impedance arc, the B10 sample of electrical insulation+coating under the protection of layer connection has greater transmission resistance and film layer resistance; electrical insulation+coating connection can effectively slow down the three corrosion tendencies of pitting, pointed and intergranular corrosion. The above results comprehensively show that the insulation+coating protection method has a better galvanic corrosion protection effect.