| Title |
Study on the Part Unit Corrosion Evaluation for Automotive Lower Arm Using Electrochemical Cyclic Corrosion Test |
| Authors |
김선홍(Seon-hong Kim); 이지훈(Ji-hoon Lee); 김정구(Jung-gu Kim); 장민(Min Jang) |
| DOI |
https://doi.org/10.3365/KJMM.2018.56.2.103 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
metals; oxides; coating; corrosion; electrochemistry |
| 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) |