What should be placed between dissimilar metals to prevent electrolytic action?

To prevent electrolytic action, which can occur when dissimilar metals come into contact in the presence of moisture, a protective separator is the best solution. This separator acts as a barrier that reduces the likelihood of galvanic corrosion, where one metal corrodes preferentially when in contact with another metal of a different electrochemical potential.

The use of a protective separator can take various forms, such as plastic or rubber gaskets, which not only keep the two metals apart but also create an isolating layer that inhibits the flow of electrical current between them. This isolation is crucial, particularly in aerospace applications where the integrity and safety of structures are paramount.

While lubrication oil, heat insulating materials, and electrical tape might serve specific purposes in particular contexts, they do not effectively address the prevention of electrolysis between metals. For example, lubrication oil primarily reduces friction and may not provide adequate separation to prevent corrosion. Heat insulating materials are designed to prevent heat transfer and do not necessarily provide a barrier to moisture or electrical conduction. Electrical tape can provide some degree of insulation but is not robust enough for structural applications, especially in environments where moisture is present and corrosion is a concern.

In summary, using a protective separator is the most effective means of preventing electrolytic action between dis