The Corrosion of Copper and Aluminum Tubes in Water Cooling Systems for Thermal Stabilization of Multi-purpose Detectors

Abstract

A scientifically substantiated forecast is given for the possibility of using a sealed copper-aluminum circuit for thermal stabilization of multipurpose detectors using distilled water as a coolant. Model installations for continuous water pumping through copper, aluminum, and mixed copper-aluminum circuits have been developed and assembled to compare the corrosion resistance of various materials. A technique for full-scale corrosion tests of closed water cooling circuits based on changes in the specific electrical conductivity of the coolant over different time intervals has been proposed for the first time. Using X-ray phase analysis, it has been established that aluminum hydroxide is the product of aluminum corrosion. Based on changes in the surface morphology of copper and aluminum revealed by scanning electron microscopy, an assumption has been made about the slow dissolution of these metals during long-term pumping of distilled water through them: with the formation of a strong but not continuous film on the surface of aluminum, and by smoothing the microrelief of the copper surface. The comparison of the change in water electrical conductivity from the time of its continuous pumping through copper, aluminum and copper-aluminum circuits for 100 days, as well as the extrapolation of the straight-line sections of the dependence of ρ on t to 365 days showed that, provided there is no direct contact between copper and aluminum, a slight increase in water electrical conductivity is observed when using Al (ρ =19 μS/cm), Cu (ρ =24 μS/cm) and mixed Cu–Al (ρ =25 μS/cm) circuits.