Corrosion Study on Single-Phase Liquid Cooling Cold Plates With Inhibited Propylene Glycol/Water Coolant for Data Centers

Abstract

Single-phase cold plate liquid cooling attracts more and more attention to high-performance computing (HPC), cloud computing, and general computing data centers for the thermal management of modern microprocessors and adjacent components due to liquid’s inherent advantage of higher specific heat compared to air. Deionized (DI) water is usually used as a coolant for liquid cooling in data centers. On the contrary, propylene glycol/water is recommended as a coolant for single-phase cold plate liquid cooling in this study for following reasons. The inhibited propylene glycol-based fluids of 25+% vol have the benefit of being biostatic and not requiring addition of biocides. They also offer freezing protection in the usage of data centers in cold climates. The cold plates made from copper is prone to oxide even under the room temperature, and the dissimilarity between brazing material and copper can also cause galvanic corrosion in the usage. In this paper, a study was carried out to investigate cold plate corrosion with inhibited propylene glycol/water using design of experiments (DOE) method. This study shows manufacturing process plays an important role on corrosion of cold plates made from copper and the corrosion risk can be mitigated by enabling new manufacturing processes, including friction stir welding (FSW) and nickel plating to the inside surface of the cold plate in the manufacturing process.