Effect of Cathodic Protection of Adjacent Steel Piles on the Life of Sacrificial Anode

J. Ocean Eng. Technol. 2008;22(3):76-81.

Moon Kyung-Man,Lee Kyu-Hwan,Cho Hwang-Rae,Lee Myung-Hoon,Kim Yun-Hae,Kim Jin-Gyeong

Dept. of Mechanical and Materials Engineering Korea Maritime Univ.,Education and Research Division Korea Institute of Maritime and Fisheries Technology,Dept. of Mechanical and Materials Engineering Korea Maritime Univ.,Dept. of Marine System Engineerin

희생양극의 수명에 미치는 인접 강파일의 음극방식 영향

문경만,이규환,조황래,이명훈,김윤해,김진경

한국해양대학교 공과대학 기계소재공학부,한국해양수산연수원 교육연구처,한국해양대학교 공과대학 기계소재공학부,한국해양대학교 해사대학 기관시스템공학부,한국해양대학교 공과대학 기계소재공학부,한국해양수산연수원 교육연구처

Keywords: Sacrificial anode, Protection current, Polarization potential, Cathodic protection, Self corrosion

핵심용어: 희생양극, 방식전류, 분극전위, 음극방식, 자기부식

Abstract

There are two cases when the life of a sacrificial anode is shortened from the designed life: one case results from self-corrosion of the anode due to contamination by sea water in the other case, however, electrical current to protect some given steel piles overflows to protect other, adjacent non-protected steel piles. In this study, the variation of polarization potential of nine steel piles, being protected cathodically and with anode-producing current between anode and steel piles, was investigated. Parameters were varied, such as the eighth and ninth steel piles either connected electrically or not, and whether the ninth steel pile was protected by another sacrificial anode or not. The current produced by the sacrificial anode decreased when the ninth steel pile was cathodically protected by the anode of another pile. However, produced current increased when the ninth steel pile was not connected to another anode. The study concludes that the life of a sacrificial anode can be prolonged or shortened depending on whether adjacent steel piles are cathodically protected or not.