Corrosion behavior of Al-alloys 3A21, 5a05 and 6063 in low-conductive ethylene glycol coolant

As a substitute of theconventional ethylene glycol coolant, low-conductive ethylene glycol coolant was developed to alleviate the corrosion of cooling plate and the blocking of circulation channels. However, scarce researches focus on it currently. In the present work, corrosion behavior of three Al-alloys, 3A21, 5A05 and 6063, in low-conductive ethylene glycol coolant was comparatively studied by methods of potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and immersion test. The results show that 5A05 has the best corrosion resistance in the low-conductive ethylene glycol coolant, which was suffered mainly from uniform corrosion along with mild local corrosion. While Al-alloys 3A21 and 6063 were suffered from pitting corrosion. The Al-alloy 6063 has the poorest pitting-corrosion resistance with the fastest thinning rate and pitting growth rate. The different corrosion behavior of the three Al-alloys in low-conductive ethylene glycol coolant can be attributed to higher Mg content and moderate Mn content of the Al-alloy 5A05.