Carrier corrosion

Anyone had problems with corrosion on the flange connections causing leaks , I think it is due to dissimilar metals , any suggestions ?

Attachment 11966

Yes,
called cathodic corrosion. Dis-similar metals and acidic / PH water levels. Basically ground electrically everything to ground induced voltages. Plus manage water quality and PH as neutral.
Do a loop impedence voltage check to see what voltages are not being grounded which are creating your problems

Thanks for the reply Magoo . I have considered bonding between the stud and the copper pipe to get them at the same potential . I should have said this is the condenser coil , the only water is rain so it would be difficult to manage the ph value :-)