On Cold Plate Corrosion with Propylene Glycol/Water Coolant

In order to address the inherent limitation of air cooling for increasing power of the server and rack in the data centers, 1-phase indirect liquid cooling has been proposed for inherent advantage of liquid’s higher specific heat than air. The inhibited propylene glycol- based fluids at 25 vol% or higher have the benefit of being biostatic and not requiring the addition of biocides. They also offer freeze protection for shipping particularly to data centers in colder climates and regions. Propylene glycol/water is recommended as coolant for 1- phase cold plate liquid cooling. The metal material for cold plate to work with inhibited propylene glycol in the secondary liquid loop is copper. It’s known that copper is prone to oxide even under room temperature and the dissimilarity between brazing material and copper can also cause galvanic corrosion in usage. A thorough study was conducted to investigate cold plate corrosion with inhibited propylene glycol/water using design of experiments (DOE) method. The chemical analysis of the collected liquid was conducted and used to correlate with liquid discolor to guide us to select appropriate manufacturing process in cold plate manufacturing.