I had recently received a CPU water block from the RMA of a friendly dealer, which I should investigate. Please “take a closer look”. That’s exactly what I did after my first inspection, because although you could see the dirt with the naked eye – how about some really fancy macro shots of the horror? And since there was just the chance to test a Keyence VHX 7000 digital microscope here in the lab, I naturally took it.
The metallic copper surface of such a cooler bottom runs through various phases of metamorphosis from a shiny block to a clogged crystal base, if not handled correctly. In our case, a cheap aluminum radiator and dubious coolant were said to have been in the system. Then it may well happen within a few months that the original copper first oxidises to copper(I) oxide (Cu2O) and then, under further sustained oxidation, is converted to green, basic copper(II) carbonate, which contains further additives such as sulphates or chlorides – depending on the composition of the coolant and the production residues in the radiator.