Papers by Keyword: Cathodic Protection Method

Abstract: A sacrificial anode cathodic protection method has been widely used in the steel pile by galvanic current by potential difference between sacrificial anode and corrosive structural steel. And, the sacrificial anode cathodic protection method have generally merits compared to impressed current method because it can be applied to everywhere which is not connected with electricity. However, when the steel piles of the pier are submerged in low conductivity solution mixed with fresh water and sea water, the structural steel piles mentioned above have not been protected occasionally perfectively due to decreasing of galvanic current caused by deposited with oxide film on the surface of anode. In this study, five types of samples which are added with NaCl(g) to Zn anode were prepared with ratio of NaCl(g)/Zn(g)x100(%). And galvanic currents, surface morphologies characteristics of these samples was investigated using electrochemical methods such as polarization curves, galvanic current and analysis of surface morphologies before and after reduction weight ratio test in order to evaluate the effect of addition of NaCl(g) affecting to quality of zinc anode. The 2.6 % sample added with NaCl(5g) showed the highest value of galvanic current density in 0.8% NaCl solution, however, the highest reduction weight ratio was also observed at the 2.6% sample. Therefore, it is considered that the higher galvanic current density, the higher reduction weight ratio, that is, the life of sacrificial anode is shorted with increasing of galvanic current. Moreover, all samples added with NaCl(g) to Zn sacrificial anode indicated higher galvanic current density compared to the sample with no addition of NaCl(g) in low conductivity solution. Eventually, it is supposed that the galvanic current can be increased with addition of NaCl(g) to Zn sacrificial anode in low conductivity solution.

Abstract: There have been two cathodic protection methods to inhibit corrosion of the structural steel piles which are being immerged under seawater, or to control corrosion of a hull part of the ship exposed to sea water. One of them is a sacrificial anode cathodic protection method that the steel pile can be protected with galvanic current by potential difference between sacrificial anode and corrosive structural steel. And, the sacrificial anode cathodic protection method have generally merits compared to impressed current method because it can be easily applied to everywhere which is not connected with electricity. However, when the steel piles are being submerged in low conductivity solution mixed with fresh water and sea water, the structural steel piles mentioned above have not been protected occasionally perfectively due to decreasing of galvanic current of zinc anode caused by deposited with oxide film on the surface of anode. In this study, four types of zinc anodes samples which are included with three types of additives such as NaCl, KCl, and ZnCl₂ were prepared, and galvanic currents, the polarization characteristics of these anodes was investigated using electrochemical methods such as polarization curves, impedance, cyclic voltammogtam and galvanic current in order to evaluate the effect of additive affecting to quality of zinc anode. The sample added with NaCl indicated the highest value of galvanic current density compared to other samples in the case of lower and higher conductivity solutions such as 0.32 and 2.97mS respectively, and the sample added with KCl revealed the smallest galvanic current density in middle value of conductivities such as 1.53 and 2.27 mS. Moreover, Zn sample no added with additive exhibited the smallest value of galvanic current density in the lowest conductivities such as 0.32 and 0.98 mS. Therefore, it is considered that the galvanic current of the sacrificial anode can be increased by adding of additive when the anode is submerged in low conductivity solution mixed with fresh water and sea water.

Abstract: Cathodic Protection Method was introduced as a corrosion protection method of metals under the ground or sea. Since 1970, it was applied to corrosion protection method of reinforced concrete structures. After 1990, this method has been used around the world, and its usability was proved. But this method has some problems on the aspect of construction and economy. In order to solve these problems, Cathodic Protection Method by using high durable metal spray was developed. First, the specimen was covered with anodic materials (Zn, Al) by using metal spray. And a performance of corrosion protection was confirmed by measuring corrosion current and halfcell potential of specimen. Through the result of experiment, it is possible to know that Cathodic Protection Method by using high metal spray is good protect to corrosion on reinforced concrete structures.