海水流速对DH36平台钢阴极保护的影响  

Effect of Flow Velocity on Cathodic Protection of DH36Steel in Seawater

作　　者：范丰钦 宋积文[2] 李成杰[1] 杜敏[1] 

机构地区：[1]中国海洋大学化学化工学院海洋化学理论与工程技术教育部重点实验室,青岛266100 [2]中海油能源发展股份有限公司北京分公司信息技术发展中心,北京100027

出　　处：《中国腐蚀与防护学报》2014年第6期550-557,共8页Journal of Chinese Society For Corrosion and Protection

摘　　要：利用自行设计的管流式海水循环实验装置模拟在0.20~2.00 m/s流速范围内的阴极保护情况,采用恒电流极化法进行阴极保护,通过电位的变化、电极宏观形貌和钙质沉积层的生成情况评价阴极保护效果。结果表明,流速越大,电位达到保护电位-800 m V(vs Ag/Ag Cl海水)时所需的电流密度越大;而且当流速大于1.20 m/s时,即使电位达到了保护电位仍可能发生明显的冲刷腐蚀;生成的钙质沉积层主要是单层的富镁层,只有电流密度较大时,才会在富镁层上进一步沉积富钙层。A series of cathodic polarization experiments for DH36 steel has been performed with seawater flow in a range of flow velocities: 0.20, 0.40, 0.60, 0.80, 1.00, 1.20, 1.40 and 2.00 m/s in a pipe flow circulating seawater device. For each flow velocity, at least three different polarization current densities were chosen to perform galvanostatic cathodic polarization for 7 d. The results showed that the current density demand for an adequate cathodic protection(CP) increased with the flow velocity; the potential could be also polarized to achieve-800 m V vs the silver/silver chloride(seawater) reference electrode(Ag/Ag Cl [sw]) when the velocity was up to 1.00 m/s; however when the velocity was above 1.20 m/s, erosion- corrosion probably could occur even the polarization potential has achieved the protective potential; the calcareous deposits formed on the steel surface were most single magnesium- rich layers. Exceptionally, calcium- rich deposits could form on top of the magnesium-rich layer only when a very high current density was applied.

关 键 词：阴极保护 海水流速 保护电流密度 钙质沉积层 恒电流极化 

分 类 号：TG174.41[金属学及工艺—金属表面处理]