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Vol.56, No.2, 103 ~ 113, 2018
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| Title |
| Study on the Part Unit Corrosion Evaluation for Automotive Lower Arm Using Electrochemical Cyclic Corrosion Test |
| 김선홍 Seon-hong Kim , 이지훈 Ji-hoon Lee , 김정구 Jung-gu Kim , 장민 Min Jang |
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| Abstract |
| This research focused on the development of the part unit evaluation for an organic coated automotive lower arm using the electrochemical cyclic corrosion test (E-CCT). The E-CCT accelerates both the coating degradation and the perforation corrosion. The applied potential for the coating degradation was determined to be -500 mVSCE for anodic polarization and -900 mVSCE for cathodic polarization. The applied current for the perforation corrosion was equivalent to the applied anodic potential. The E-CCT was conducted for the duration of 8 cycles, which is considered to be equivalent to 4 years of driving. After the E-CCT, the coating degradation was evaluated by electrochemical impedance spectroscopy (EIS) measurements. Especially, the Z100 mHz value (impedance value at a frequency of 100 mHz) of the part unit represented the amount of corrosion damage of the lower arm parts. The Z100 mHz of the degraded coating area had a decisive effect on the Z100 mHz value of the entire lower arm. This result was caused by electrochemical interaction between the non-degraded coating area and degraded coating area. The non-degraded coating area and the degraded coating area of the lower arm formed the parallel circuit which provides a satisfactory result.
(Received July 24, 2017; Accepted December 11, 2017) |
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| Key Words |
| metals, oxides, coating, corrosion, electrochemistry |
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