Influence of Current Density Application Time on the Corrosion Damage of Offshore Wind Steel Substructure in Galvanostatic Corrosion Experiment
해상풍력 하부 구조물용 강재의 정전류 부식 시험 시 전류밀도 인가 시간이 부식손상에 미치는 영향
이정형;박재철;한민수;장석기;김성종;
Lee, Jung-Hyung;Park, Jae-Cheul;Han, Min-Su;Jang, Seok-Ki;Kim, Seong-Jong;
목포해양대학교 기관시스템공학부;(사)한국선급;
Division of Marine Engineering, Mokpo National Maritime University;Korean Register;
DOI : 10.5695/JKISE.2016.49.5.431
This research investigated the relationship between the corrosion damage characteristics of offshore wind steel substructure and the time of current density application by electrochemical accelerated short-term corrosion test. The galvanostatic corrosion was conducted on the steel specimens in natural seawater with a constant current density ranging from $1mA/cm^2$ to $200mA/cm^2$ for 1 ~ 180 min. Macro and micro observation was carried out on the surface of the corrosion damaged area using SEM and 3-dimensional analysis microscope. The weight loss of the specimens before and after was calculated as the difference between the initial weight prior to corrosion and weight after removal of the corrosion product. It was shown that during galvanostaic corrosion process, the corrosion behavior could be characterized by the onset of pitting corrosion in the early stage and the uniform corrosion in the late stage, showing damage development in the depth direction with the time of current application. The result of the 3D analysis revealed that both damage depth and surface roughness increased with increasing time of current application. The weight loss curves with time showed that a coefficient of determination ($R^2$) was relatively high for the relationship between the time of current application and weight loss. As a result, the degree of corrosion can be controlled by simply varying the time of current application.