Change in Electrochemical Impedance Spectrum of Coated Steel Plate by High Temperature・High Humidity-Cold Cycle test

Abstract

Painted steel panel uses for automotive body. Therefore, assessments of painted steel corrosion protecting life are important. Automotive body is exposed to various atmospheric environments. Atmospheric environmental factors (temperature, humidity, adhering salt type, etc.) are influenced on corrosion protecting life of the painted steel. In order to evaluate the corrosion protection performance in a short time, we study evaluation of coating film degradation using EIS (Electrochemical Impedance Spectroscopy) . As a result, it was found that coating thickness, adhesion salt type and presence/absence of freezing process may contribute to degradation of corrosion protection performance.

Change in Electrochemical Impedance Spectrum of Al/CFRP Adhesive Lap Joint by High Temperature, High Humidity-Cold Cycle Test

“…The tests were performed in constant low temperature/humidity chamber (THE051FA) made by Toyo Engineering Works, Ltd. Similar to a previous report, 11) a mixture of 98 mass% NaCl1 mass% CaCl 2 1 mass% MgCl 2 (40 mg•cm ¹2 ) that imitated the snow-melting salt used in cold regions was applied to the joint.…”

“…Examining the degradation of adhesive joints in severe corrosive environments such as cold regions is particularly useful, as the corrosion of coated steel plates was proved to be promoted in such an environment in a previous study. 11) Therefore, we investigated the changes in the impedance and dielectric loss tangent of CFRP and metal (aluminum) joints by various adhesives, which are indispensable for the multi-materialization of automobiles, in corrosive environments such as cold regions through EIS.…”