ME06: GALVANIC CORROSION TABLE (GALVANIC VOLTAGES RELATIVE TO GOLD)

METALINDEX [V]
Most cathodic (most noble)
Gold, solid and plated; gold-platinum alloy-0.00
Rhodium-plated on silver-plated copper-0.05
Silver, solid or plated; monel metal; high nickel-copper alloys-0.15
Nickel, solid or plated; titanium and its alloys; monel-0.30
Copper, solid or plated; low brasses or bronzes; silver solder; German silvery high copper-nickel alloys; nickel-chromium alloys-0.35
Brass and bronzes-0.40
High brasses and bronzes-0.45
18%-chromium-type corrosion-resistant steels-0.5
Chromium plated; tin plated; 12%-chromium-type corrosion-resistant steels-0.6
Tin-plate; tin-lead solder-0.65
Lead, solid or plated; high lead alloys-0.7
2000 series wrought aluminium-0.75
Iron, wrought, gray, or malleable; low alloy and plain carbon steels-0.85
Aluminium, wrought alloys other than 2000 series aluminium, cast alloys of the silicon type-0.9
Aluminium, cast alloys (other than silicon type); cadmium, plated and chromate-0.95
Hot-dip-zinc plate; galvanized steel-1.2
Zinc, wrought; zinc-base die-casting alloys; zinc plated-1.25
Magnesium and magnesium-base alloys; cast or wrought-1.75
Beryllium-1.85
Most anodic (least noble)

For high humidity and salty (harsh) environments, outdoors there should be no more than 0.15V difference in the anodic index of the two metals. This is 0.25 for normal conditions like warehouses and 0.5 for air controlled rooms.

The main logic is the closer two metal to each other in the table, they will be more suitable to use together.