Corrosion in Liquid Cooling Systems with Water-Based Coolant – Part 1: Flow Loop Design for Reliability Tests

With increasing thermal loads in electronic packages, liquid cooling is a preferred option for superior cooling capability. Closed loop liquid cooling systems with microchannel cold plates have demonstrated superior thermal performance. The widespread adaptation of this technology, however, is subject to long term reliability concerns, especially caused by corrosion with a water-based coolant. Galvanic corrosion, which is caused by the difference in electrode potentials is observed to be the dominant failure mechanism. In this paper, the design and development of flow loops suitable for capturing the corrosion behavior within the loop is discussed. Careful consideration of all components within the loop and the rationales behind the choices are highlighted. The experimental methodology details various sensors and measurements required to assess corrosion development in the loop. Experimental results from the flow loop tests are presented and engineering recommendations are made for flow loop design, choice of working fluid and measurements to be made in-situ. Although there is a clear indication of corrosion progression based on the experimental data of fluid chemistry degradation, no significant impact is observed on thermal performance of the current microchannel cold plate design for the duration of the current test conditions.