Report on simple accelerated corrosion tests on the corrosion of copper by the chloride ions contained in groundwater

Abstract

A high concentration of chloride ions was detected from the groundwater in hilly and mountainous areas of the Chugoku Region. An electric water heater, which had used this high chloride groundwater, failed after a short term due to corrosion, etc. In general, low corrosive metals, such as copper, are used for electric water heaters. Thus, the relationship between the cause of failure and the high chloride concentration is considered to be close. In this report, firstly, we showed the relationship between the high concentration of chloride ions included in groundwater and the cause of the failure of an electric water heater. Simple corrosion tests were carried out to estimate the relationship between the lifetime of copper and the degree of corrosion affected by the chloride concentration. As a result, it was found that corrosion may occur in corrosion-resistant copper in ten years under high temperature and high humidity conditions even if the chloride concentration is about 20 mg/L.