Copper Stainless Steel Reaction

I am constructing a project utilizing a knock down aluminum tube frame.

Copper stainless steel reaction.

The elbows must be permanently joined to one frame member at each knock down joint. In addition the area ratio of stainless steel to copper altered copper corrosion behavior. These metals are used because of their durability and long lifespans. Galvanic corrosion can be controlled by the use of sacrificial anodes isolation of the metals from electrical continuance protective plastic coatings or epoxy coatings or with corrosion inhibitors.

I wish to use hard copper elbows to join aluminum tube frame members. In the copper stainless steel couple the open circuit potential of stainless steel was found to play a decisive role. Lead and copper are quite close on the nobility table to stainless steel and so the bimetallic corrosion risks should be small. Iron and steel are generally not a problem unless their mass is similar or smaller than that of the copper.

Corrosion issues with aluminum copper and stainless steel 2004. The principal metals of concern in terms of direct contact are aluminum and zinc. If copper is connected to stainless steel type 304 then the copper will corrode to sacrifice to the stainless steel. It is not necessary to isolate copper from lead tin or stainless steel under most circumstances.

In most cases when stainless steel was in the passive state and acted as the cathode the contact accelerated copper corrosion.