The galvanic corrosion rate depends on the electrical potential between the two metals. The Galvanic Series (fig. 2) orders metals based on the potential they exhibit in flowing seawater. The most reactive are at the top of the table and the least reactive at the bottom.
Elevated temperatures, which are likely in cooling loops, accelerate galvanic corrosion. A 10°C increase in temperature can approximately double the corrosion rate. Corrosion inhibitors can be added to the cooling water. This slows, but does not eliminate, galvanic corrosion. Corrosion inhibitors bind with the ions in solution to neutralize them. The inhibitors are consumed in this process so they need replacing regularly. Non-aqueous coolants, such as oils, eliminate galvanic corrosion because they do not support ions. However, thermal performance is sacrificed, as the thermal conductivities of heat transfer oils are generally significantly lower than water-based coolants.
To avoid galvanic corrosion, we highly recommend using the same materials, or materials with similar electrical potential, throughout your cooling loop. You should ensure that plumbing, connectors and other components do not introduce a reactive metal into the system.
Using the same materials throughout your circuit does not mean that you must sacrifice performance. Boyd offers high performance heat exchangers and cold plates with aluminum, copper and stainless steel fluid paths.
Boyd’s application engineers are available to consult on component material compatibility. With careful design and component selection, you can ensure years of reliable, corrosion free service from your cooling loop.
Check out our Ambient Liquid Cooling Systems or our Recirculating Chillers.