Effects of temperature on dezincification and electrochemical behaviour of 70—30 brass in sulphuric acid

This paper presents the results of experiments to investigate the effects of temperature on the dezincification and corrosion of 70–30 brass in 0·5 M H2SO4, Zinc and copper losses from specimens tested at various temperatures were estimated at various time intervals by atomic absorption spectroscopic analysis of the corrodent. Corrosion of the brass as a whole was studied by electrochemical techniques. Attacked surfaces were analysed by optical metallography, scanning electron microscopy and energy dispersive X-ray analysis (EDAX). The results show that at temperaturesbelow 50°C the potential remained more or less constant at −400 m V(SCE) forthe duration of the test. An electropositive shift in potential was observed at temperatures above 50°C. Potentiostatic polarisation curves were also shifted to lower current densities at temperatures above 50°C. Dezincijication 0f 70–30 brass hasbeenfound to take place by different mechanisms depending on temperature.