碳钢/Ti和碳钢/Ti/海军黄铜在海水中电偶腐蚀的研究

采用动电位极化技术及失重法研究Q235B碳钢/TA2钛和Q235B碳钢/TA2钛/海军黄铜在海水中的电偶腐蚀规律.测定了Q235B碳钢、TA2钛和海军黄铜在海水中的自然腐蚀电位、腐蚀速率和稳态极化曲线,测定了不同面积比时电偶对电偶电流的大小、方向,电偶电位以及电偶对阳极和阴极的失重速率,由电偶对不同面积比的数据得到Q235B碳钢被Ti电偶极化的动态极化曲线.结果表明,阳极的腐蚀速率随阴/阳极面积比的增大而增加;阳极腐蚀速率随阴/阳极面积比的增大有一个极限值,即当阴/阳极面积比大于这个极限值时,阳极腐蚀速率不再增加.这三种金属构成的电偶对,海军黄铜是这个系统的阴极,受到碳钢的保护.

GALVANIC CORROSION OF CARBON STEEL/TITANIUM AND CARBON STEEL/TITANIUM/NAVEL BRASS IN SEAWATER

The natural corrosion potential, corrosion rate and steady- state polarization curves of Q235B carbon steel, TA2 titanium and navel brass in seawater were measured. The galvanic current, galvanic potential and galvanic corrosion rate of anode and cathode of couple with different area ratio, at different temperature and different velocity of seawater were measured. According to the data of the couple with different area ratio, a dynamic polarization curve of Q235B carbon steel was obtained. The galvanic corrosion characters of Q235B carbon steel / TA2 titanium and Q235B carbon steel/TA2 titanium/navel brass in seawater were investigated. The results showed that corrosion rate of anode increased with increasing of area ratio of cathode/anode, temperature and velocity of seawater. But there was a limited area ratio. The corrosion rate of anode did not increase when area ratio of cathode/anode was larger than the limit. When the galvanic couple consists of the three metals, navel brass was cathode in the system and was protected by carbon steel.