Study of Corrosion on Film Properties of High Strength Cu-Sn-Zr Alloys in Tap Water

Abstract

Corrosion has been reported to occur in the copper tubes of heat ex-changers in multiple-circulation hot water supply systems. We have been investigating the applicability of high-strength Cu-0.65 mass% Sn-0.014 mass% Zr-0.020 mass% P alloy to counteract this corrosion. Immersion tests, electrochemical measurements, and field tests were performed. Excellent corrosion resistance of the alloy was established under conditions with flowing water due to the formation of composite films containing tin. The alloy is expected to be better than copper as a corrosion-resistant material for heat exchanger tubes.