전해부식시험을 이용한 니켈-크롬도금강판 및 아연도금강판의 내식성 비교평가시험

Abstract

An Eectrolytic Corrosion(EC) test method was evaluated by the comparison with Copper Accelerated Acetic Salt Spray(CASS) and Neutral Salt Spray(SS) tests. Those methods were applied in order to evaluate corrosion resistance of Ni-Cr plated and Zn-plated Fe substrates. The correlations between results obtained by different test methods were investigated. Results showed that the electrochemical method such as the EC test method was superior to the conventional methods such as CASS and SS, in terms of the quantitative accuracy and the test-time span. Furthermore, the EC test method provided the useful means to estimate the initiation of corrosion of each layer by monitoring the rest potentials of the coated layers such as Ni, Cr, and Zn on Fe substrate. With regard to test time spans, the EC test provided the 78 times and 182 times faster results than the CASS test in cases of Fe + 5㎛ Ni + 0.5 ㎛ Cr and Fe + 20 ㎛ Ni + 0.5 ㎛ Cr respectively,while the EC test was 85 times faster results than the Salt Spray test in the case of Fe + 20 g/m2 Zn. Therefore, the EC test can be the better method to evaluate the resistance to corrosion of coated layers than the conventional methods such as the SS test and the CASS.