Galvanic Series, or Nobility Chart for Dissimilar Metals
Use this chart to avoid galvanic corrosion in seawater when different metals come in to contact. Alloys with higher nobility are at the top, and metals that are less noble (or more base) are at the bottom.
How to read and apply the Galvanic Series chart above
Galvanic corrosion of the least nobel alloy can be a serious issue when two different alloys are coupled together or touching. The chart above gives the voltage difference when dissimilar metals are in a seawater environment. If the alloys are different you can always expect SOME galvanic corrosion, but it's not usually a concern unless the voltage difference between the two metals is 0.2v or more.
For example, manganese bronze fittings could be fastened with silicon bronze bolts in a sea water environment and experience little to no galvanic corrosion because the voltage difference is so very small. However, mild steel or stainless steel screws or bolts would cause an adverse reaction and lead to significant galvanic corrosion on that same manganese bronze fitting.