Galvanic corrosion & your razor/blade

I've been hanging around here a while and have seen many interesting things said, but never have I heard mention of a thing called "Galvanic Corrosion".

Of course, why would I? The majority of blades are of stainless steel and impervious to corrosion, right? Razors are protected by nickel, chrome, etc., so they can't be affected either, right?

No, not really.

Galvanic corrosion:

Long version: http://en.wikipedia.org/wiki/Galvanic_corrosion

Short version: If you have 2 different metals which are covered with a conducting liquid like water, soapy water, or, if you are having a bad day, bloody soapy water, then one or the other will beging corroding!

Galvanic corrosion occurs in an entirely predictable way and the following table will give a listing from More to less active metals. The thing to remember here is that metals higher on the list will be corroded in contact with those lower in the list.

(reference link: http://www.eaa1000.av.org/technicl/corrosion/galvanic.htm)

Corrosion Control - Galvanic Table
Lee Erb
Originally published August 1997

Listed below is the latest galvanic table from MIL-STD-889. I have numbered the materials for future discussion of characteristics. However, for any combination of dissimilar metals, the metal with the lower number will act as an anode and will corrode preferentially.

The table is the galvanic series of metals in sea water from Army Missile Command Report RS-TR-67-11, "Practical Galvanic Series."

The Galvanic Table

Active (Anodic)

Magnesium
Mg alloy AZ-31B
Mg alloy HK-31A
Zinc (hot-dip, die cast, or plated)
Beryllium (hot pressed)
Al 7072 clad on 7075
Al 2014-T3
Al 1160-H14
Al 7079-T6
Cadmium (plated)
Uranium
Al 218 (die cast)
Al 5052-0
Al 5052-H12
Al 5456-0, H353
Al 5052-H32
Al 1100-0
Al 3003-H25
Al 6061-T6
Al A360 (die cast)
Al 7075-T6
Al 6061-0
Indium
Al 2014-0
Al 2024-T4
Al 5052-H16
Tin (plated)
Stainless steel 430 (active)
Lead
Steel 1010
Iron (cast)
Stainless steel 410 (active)
Copper (plated, cast, or wrought)
Nickel (plated)
Chromium (Plated)
Tantalum
AM350 (active)
Stainless steel 310 (active)
Stainless steel 301 (active)
Stainless steel 304 (active)
Stainless steel 430 (active)
Stainless steel 410 (active)
Stainless steel 17-7PH (active)
Tungsten
Niobium (columbium) 1% Zr
Brass, Yellow, 268
Uranium 8% Mo.
Brass, Naval, 464
Yellow Brass
Muntz Metal 280
Brass (plated)
Nickel-silver (18% Ni)
Stainless steel 316L (active)
Bronze 220
Copper 110
Red Brass
Stainless steel 347 (active)
Molybdenum, Commercial pure
Copper-nickel 715
Admiralty brass
Stainless steel 202 (active)
Bronze, Phosphor 534 (B-1)
Monel 400
Stainless steel 201 (active)
Carpenter 20 (active)
Stainless steel 321 (active)
Stainless steel 316 (active)
Stainless steel 309 (active)
Stainless steel 17-7PH (passive)
Silicone Bronze 655
Stainless steel 304 (passive)
Stainless steel 301 (passive)
Stainless steel 321 (passive)
Stainless steel 201 (passive)
Stainless steel 286 (passive)
Stainless steel 316L (passive)
AM355 (active)
Stainless steel 202 (passive)
Carpenter 20 (passive)
AM355 (passive)
A286 (passive)
Titanium 5A1, 2.5 Sn
Titanium 13V, 11Cr, 3Al (annealed)
Titanium 6Al, 4V (solution treated and aged)
Titanium 6Al, 4V (anneal)
Titanium 8Mn
Titanium 13V, 11Cr 3Al (solution heat treated and aged)
Titanium 75A
AM350 (passive)
Silver
Gold
Graphite
End - Noble (Less Active, Cathodic)

Did that give you food for thought?

OK...so I'm a numbers guy not an engineer but I work closely with our engineers and my understanding is that the closer the two metals are on the list the slower and less the corrosion effect. Looking at the list steel/chrome/nickel/brass are all very close on the table.

Do you know what the difference between active / passive stainless and the number?

Unfortunately, I'm not a metallurgical engineer and can't say with certainty which situation the active/passive notations refer to. I would imagine it either has to do with the presence of a protective oxide on the surface (passive) or its absence (active). It could also refer to an externally applied charge.

For practical purposes it is likely irrelevant as we know not which stainless a given blade is made of and the chart is constructed presuming seawater as the electrolyte. If you change the electrolyte the series may change. Deconstructing the soapy water from your shave to determine its exact properties as an electrolyte and attempting to crunch the numbers would be a challenge beyond my time limitations. You are welcome to it!

I've already ruined a few new blades by failing to clean propely after a shave, as well as lending out a razor and having it come back severely pitted after being stored "in the shower". You are welcome to run that experiment as well. lol

I dry my razor and blade every day. Even so I have extremely hard water and at the end of a week of so the Astra SPs, or previously Derbys, will show stains on the blades that I assume are corrosion. I think as well as the Glavanic Corrosion we also have to remember that to some extent the soaps and creams have to introduce a slight acid or base to the metal. What effect that has I don't know and its probably moot as a blade changed every week is probably removed before to much damage occurs.

Jay

You would need an electrolyte, or an electric current, in order for ion migration (meaning corrosion) to begin. Soapy water is a mild base, but the length of exposure is insufficient for corrosion to occur, particularly considering the stainless steel razor blades, and the chrome, nickel, or gold plating typically used on razors (specifically to ward off corrosion). Rinse, and allow your razor and blades to dry, and galvanic corrosion should not be an issue.

T-Dog said:

You would need an electrolyte, or an electric current, in order for ion migration (meaning corrosion) to begin. Soapy water is a mild base, but the length of exposure is insufficient for corrosion to occur, particularly considering the stainless steel razor blades, and the chrome, nickel, or gold plating typically used on razors (specifically to ward off corrosion). Rinse, and allow your razor and blades to dry, and galvanic corrosion should not be an issue.

Click to expand...

+1

Basically, if galvanic corrosion was an issue there wouldn't be 100 year old Gillette, GEM, Star, Kampe or other razors around...

T-Dog said:

the length of exposure is insufficient for corrosion to occur,

.

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Tell that to my poor pitted superspeed, huh. Point being if people store their razors with no concern for conditions, then they CAN be exposed long enough to do damage. Water, especially soapy water (which cleans using ionic activity mind you), is a good electrolyte. You can test that by throwing your loaded razor in a bowl of shavewater overnight and then trying to shave with it tomorrow.

Please do! It will be noticeably sharper in the morning. I promise! (lol)

Nobody said:

Tell that to my poor pitted superspeed, huh. Point being if people store their razors with no concern for conditions, then they CAN be exposed long enough to do damage. Water, especially soapy water (which cleans using ionic activity mind you), is a good electrolyte. You can test that by throwing your loaded razor in a bowl of shavewater overnight and then trying to shave with it tomorrow.

Please do! It will be noticeably sharper in the morning. I promise! (lol)

Click to expand...

Simple rinsing and drying of the razor is enough to slow, if not completely stop, galvanic corrosion. Again, if it weren't, there wouldn't be 100+ year old safety razors around.

Nobody said:

Tell that to my poor pitted superspeed, huh. Point being if people store their razors with no concern for conditions, then they CAN be exposed long enough to do damage. Water, especially soapy water (which cleans using ionic activity mind you), is a good electrolyte. You can test that by throwing your loaded razor in a bowl of shavewater overnight and then trying to shave with it tomorrow.

Click to expand...

By "length of exposure" I meant the amount of time your razor and blade are exposed during a normal shave. Soaking overnight in soapy water may be good for for your frying pan, but not your vintage razor.