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The Galvanic Series
ANODIC OR LEAST NOBLE END (Active)
Millivolts (mV)
Magnesium (Mg)
-1
Magnesium (2% Manganese (Mn))
-1
Magnesium (9%Aluminum (Al), 1% Mn,1.5% Zinc (An))
-1
Galvanized Iron (hot dipped)
-1
Zinc Electroplating
-1
Cadmium (Cd) Zinc Solder (71%/29%)
-1
Zinc (Zn)
-1
Cadmium (Cd)
-
Cadmium Plated Steel (Cd 0.001 in.)
-
Aluminum (Marine Alloys 5086, 5083, 6061)
-
Mild or Structural Steel(A36)
-
Alloy Steel
-
Aluminum (forged alloy)
-
Stainless Steel (316,317,321,347,302,304 — active, oxygen starved)
-
Tin (Sn)
-
Manganese Bronze, CA-464 Naval Brass (58%Cu,39%Zn,1%Alum,0.25%Mg)
-
Naval Brass (60% Copper, 39% Zinc)
-
Yellow Brass
-
Admiralty Brass (70% Copper, 29% Zinc)
-
Copper CA-110 (Cu)
-
Brass (60% copper, 40% zinc)
-
Gunmetal (88% Copper, +Tin)
-
Silicon Bronze (96% Copper, 1.5% Silicon)
-
Tin Bronze
-
Lead (Pb)
-
Copper/Nickel (CA-715 - 70% Cu, 30%Ni)
-
Aluminum Bronze (90% Copper, 10% aluminum)
-
Stainless Steel (316,317,321,347,302,304 — passive, oxygenated)
-
Monel 400 & 500
-
Titanium (Ti)
-
Silver (Ag)
Graphite and Carbon Fiber (C)
(+
Platinum (Pt)
(+
CATHODIC OR MOST NOBLE END (Passive)
Millivolts (mV)
• All measurements taken relative to a silver/silver chloride
(Ag/AgCl) electrode, at 77
˚
F.
• The sign of potential applies with the negative (black) probe
of the voltmeter connected to the reference electrode, and
positive (red) terminal connected to the fitting being tested
• If using a zinc reference electrode, add 100 mV to the poten-
tial. For instance, silicon bronze is - 260mV, then + 100 mV =
-160 mV.
• Average variability of potential is ±40 mV for alloys with iron
and/or nickel. ±20 mV for copper-based alloys without nickel.
• Readings 200 to 400 mV more negative (more anodic) th
given indicate the material is protected.
• Readings at or near those given, up to 200 mV above tho
given, indicate the material is unprotected and freely corr
ing.
• Readings over 400 mV more negative than given indicate
overprotection.
• Stray current corrosion is indicated by metals reading mor
cathodic (more positive) than indicated on the table.