Thread: Sacrificial anode

Aluminum forms spontaneously a non-reactive aluminum-oxide film on its surface that inhibits further corrosion. This is called passivation.

This protective film makes aluminum unsuitable as a sacrificial anode, but special aluminum alloys have been developed that do not passivate.

In other words your experiment did not work because you can't use regular aluminum as a sacrificial anode.

The reason that rust formed only on the side that was "up" is that more oxygen is available closer to the surface of the water.

Sacrifical anodes can only be used with an electrolyte (like the water in the experiment). So it's not possible to use this method of protection with objects like razors.

A more practical way to protect a blade made of carbon steel is to keep it clean, and coat it with oil before you store it (even cooking oil will do).

Even better solution: switch to stainless steel.

Originally Posted by baglamas

Aluminum forms spontaneously a non-reactive aluminum-oxide film on its surface that inhibits further corrosion. This is called passivation.

This protective film makes aluminum unsuitable as a sacrificial anode, but special aluminum alloys have been developed that do not passivate.

In other words your experiment did not work because you can't use regular aluminum as a sacrificial anode.

The reason that rust formed only on the side that was "up" is that more oxygen is available closer to the surface of the water.

Sacrifical anodes can only be used with an electrolyte (like the water in the experiment). So it's not possible to use this method of protection with objects like razors.

A more practical way to protect a blade made of carbon steel is to keep it clean, and coat it with oil before you store it (even cooking oil will do).

Even better solution: switch to stainless steel.

I was going to revolutionize the razor industry!

But my innovation now sits rusting in a bucket on my desk....

I coulda been a contender

It won't work out in the air without an electrolyte but you could always store it in water! (Imagine recommending that to someone)

Originally Posted by baglamas

Aluminum forms spontaneously a non-reactive aluminum-oxide film on its surface that inhibits further corrosion. This is called passivation.

This protective film makes aluminum unsuitable as a sacrificial anode, but special aluminum alloys have been developed that do not passivate.

In other words your experiment did not work because you can't use regular aluminum as a sacrificial anode.

The reason that rust formed only on the side that was "up" is that more oxygen is available closer to the surface of the water.

Sacrifical anodes can only be used with an electrolyte (like the water in the experiment). So it's not possible to use this method of protection with objects like razors.

A more practical way to protect a blade made of carbon steel is to keep it clean, and coat it with oil before you store it (even cooking oil will do).

Even better solution: switch to stainless steel.

I was wondering if that was the problem. Would magnesium work then?

I thought this method was also used with pipelines, to reduce corrosion.

I have noticed a similar effect when I was etching razors--the one-sized thing, that is. I think it has to do with bubbles getting trapped on one side of the blade or something. Anyway, if one side of the blade is down and the other is up, the down side doesn't etch very well.

Josh

This came up out of a thread over at B&B and I'll repeat what I said there. Those living in the S.W where we use evaporative coolers to cool our homes in summer will put an anode in the water in the tank and attach it to the metal chassis and the anode is about 4 inches or so long and an inch or so thick and at the end of a season the anode is totally gone and the chassis is clean. I really don't know what the anode is made of. I used to think zinc.

So the anode idea is a no go because the razor would have to be submerged in water.

Originally Posted by baglamas

Even better solution: switch to stainless steel.

Them's fightin' words, sir.








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Sacrafichal anode is a good idea, but if u want to be simple about it just store naked blades in oil. lol, oh and one last thing, water isnt an electrolyte, tap water is, because of impruities, but distilled water, aka pure H2O is not,

My guess?

Aluminium forms a tough oxide layer that makes it impervious to further corrosion.

Try a metal like Zinc (most popular industrial sacrificial annode) and you might find a difference.

The general rule of thumb is that the more reactive the anode the better the protection.

Okay, I'm going to bed soon, I have an exam tomorrow, I'll tell more later.

But I can tell you a sacrificial anode is a PREVENTIVE method. It will create a galvanic cell helping in protection of the metal you want to keep.

I think what happened in your case was a mix of galvanic cell and differential aeration cell, so your sacrificial side became the up and the down became protected.

I could try to scan a few diagrams for you. But for the records I think a sacrificial anode for a razor is a bad idea. Cleaning and oiling will be easier and more efficient.


As for the sacrificial anode, magnesium would be the best. That's what is in the water tanks.