Al基牺牲阳极的生物污损——“阳极苞”的解析

Biofouling of Al based sacrificial anode——analysis of “anode bract”

本文介绍了铝(Al)基牺牲阳极在青岛中港海鸥浮码头超期服役五年半的阴极保护情况。现场勘查结果发现少部分 Al阳极是以"苞"状出现,暂命名为"阳极苞"。其外层为以苔藓虫(Bryozoa/Polyzoa)为主体的生物群落构成的具有一定强度的生物硬壳,内层为白色膏状物,暂命名为"阳极泥"。对生物硬壳进行了生物鉴定,利用扫描电镜(scanning electron microscope,SEM)测试其微观结构,红外光谱(infrared spectroscopy,IR)测定其化学组成,结果表明该生物硬壳由复杂的有机混合物组成,并且具有微米级多孔结构;对"阳极泥"进行了酸碱性测定、能谱分析(energy dispersive spectrometer,EDS)及 X射线衍射(X-ray diffraction,XRD)分析,结果表明"阳极泥"主要由铝的水合氧化物和污损生物的代谢产物及机体分解产物组成。在此基础上初步讨论了"阳极苞"的形成过程及其对阴极保护的影响。

This paper introduces the cathodic protection situation of Al based sacrificial anode in Qingdao Zhong-gang seagull floating dock which extended service five and a half years, field investigation showed that a small part of Al anodes appeared in the form of "bract", tentatively named "anode bract". The outer layer is a biological hard shell composed of a biological group with bryozoan as the main body, and the inner layer is a white paste, which is called "anode mud" in this paper. The biological shell was identified by bioassay, scanning electron microscopy (SEM) was used to test its microstructure, infrared spectroscopy (IR) was used to determine its chemical composition , the results show that the biological shell consists of complex organic mixtures, and it has micron scale porous structure;at the same time, we have carried out acid base test, energy spectrum analysis (EDS) and X ray diffraction (XRD) analysis of "anode mud", and results show that the anode mud is mainly composed of the aluminum oxide hydrate and the metabolites and decomposition products of fouling organism. On this basis, we have discussed the formation process of "anode bract" and its influence on cathodic protection.