In case anyone is interested and for sake of completeness the addition of Sodium Molydbate at approximately 0.1% concentration did the trick, eliminating the solder corrosion.
Thanks for the responses appreciate it
lighterthief
Thanks for the responses, I have undergone a new set of corrosion tests using an addition of sodium molybdate to see how that effects my results.
As for using Calcium Hydroxide I think that is a no-go looking at the Health Risks of using it on an industrial scale.
The acid of question is 2-ethyl hexanoic acid, however it is reacted with a base (potassium hydroxide) to for a potassium salt, so there shouldnt be much free acid in the heat transfer system.
I am actually working in the automobile coolants buisness, as part of the procedure for developing new products we need to ensure that they do not corrode a selection of metals. The coolant I am working on performs well against everything but the solder. I'm afraid I cant simply go and buy an...
Thanks for the responses, Im afraid the solder is non-negotiable, the solder type is ASTM Alloy Grade 30A (SAE 3A). I am working on finding the exact make up of the solder which I will post as soon as I can.
The heat transfer fluid is water with a 5% organic acids as corrosion inhibitors...
