Corrosion in a closed-loop electronic device cooling system with water as coolant and its detection

This paper presents highlights of an investigation to develop methods of monitoring corrosion risk of a waterbased, closed-loop cooling system and also to identify the mechanism of reliability threats by corrosion. The current investigation finds that an array of multiple, in-line sensors is necessary to track the change in stability of the cooling system against corrosion. The coolant pressure and the flow-rate sensors are necessary to detect clogging resulting from scale deposition. On the other hand, pH and electrical conductivity sensors are needed to measure the cumulative corrosion activity. It is further found that the corrosion activity is alarmingly high in a closed-loop cooling system with a high Cu surface area relative to the coolant volume. Slowly developing failure both by flow blockage and a localized corrosion within a cold plate is observed. The rate of failure is seen to be fastest, when the starting coolant is untreated, while it decreases with deionization and inhibition treatment of water.