아연 이온화 장치의 상수 중 철 시편과 수도 배관에 미치는 부식억제 효과 예측

Abstract

This study quantitatively investigated the inhibition effect of corrosion on iron coupons and water pipes by ionization of zinc metal in tap water line. After installing iron coupons into water pipes and running tap water for 20 days, the average difference of the annual corrosion rates calculated from the weight losses of iron coupons with or without the ionization device was estimated to be 12.8 %. Comparing corrosion rates with or without corrosion inhibitor on new iron coupons showed higher difference in corrosion rates, but over time, the difference of corrosion rates between absence and presence of inhibitor had decreased gradually. It was also confirmed that the less rust-free pure iron area on the iron specimen and the less pure iron surface to react with oxygen in water gradually reduces the corrosion rate. X-ray diffraction analysis of the rust generated on iron coupons confirmed that most of them were red hematite(Fe₂O₃), and that some of the blackish parts were magnetite. It is known that the rust generated causes red tap water to fall, some of which develop into foot corrosion, resulting in pin-holes in the water pipes. Therefore, based on existing research results, we predicted the breaking time due to foot corrosion of iron coupons with or without corrosion inhibitors. Zinc corrosion suppressors were installed in water pipes where corrosion had already progressed and rusted, and the internal surface of the water pipes was observed to increase the relative ratio of the black magnetite components over time, and it was believed that corrosion suppressors could be expected for a long time.