I'd get a book on Galvanic corrosion (dissimilar metals) and study the standard practices. EX: Alum washer under the head of a steel bolt where it contacts an Aluminum surface. Prevents the Aluminum surface (Anode)from pitting and the washer is sacrificial.
A quick version.
https://www.assda.asn.au/technical-i...etal-corrosion
A bit more info.
https://www.faa.gov/documentLibrary/...r/AC_43-4B.pdf
And from the experts. Navair 01-1A-509-1 is the introduction to corrosion manual.
https://www.nsncenter.com/Library/TM/TM-1-1500-344-23-1