Galvanic corrosion

[Man with no name]

I had to respoke a second wheelset this week as a result of the chemical reaction between alu spoke nipples and carbon rims.

 

Has anybody else had a similar experience?

 

This is caused by the catalytic reaction between the alu nipples and the carbon rims facilitated by the presence of salt water (I live in CT). Considering that a large portion of the population globally live at the coast, does this point to a design flaw?

 

https://en.m.wikipedia.org/wiki/Galvanic_corrosion?wprov=sfla1

 

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[MTBeer]

I had to respoke a second wheelset this week as a result of the chemical reaction between alu spoke nipples and carbon rims.

 

Has anybody else had a similar experience?

 

This is caused by the catalytic reaction between the alu nipples and the carbon rims facilitated by the presence of salt water (I live in CT). Considering that a large portion of the population globally live at the coast, does this point to a design flaw?

 

https://en.m.wikipedia.org/wiki/Galvanic_corrosion?wprov=sfla1

 

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can't you just use brass nipples?

[Man with no name]

can't you just use brass nipples?

You can and this is what I have now done, but it seems most pre built wheelsets do not do this, hence my point on design flaw

 

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[Fat Boab]

Interesting link here, specifically on CF.....

 

https://www.corrosionpedia.com/2/1556/corrosion/galvanic-corrosion-of-metals-connected-to-carbon-fiber-reinforced-polymers

[johannrissik]

Interesting, thanks.

 

This might help explain why some of the earliest bikes that had carbon tubing and aluminium lugs had so much corrosion on the lugs?

[Plentipotential]

Aluminium nipples are the most common because it's a cheaper material to buy and work as well as a lighter material than stainless or brass. Brass is cheap to work but more expensive as a raw material than stainless. The best combination would be aluminium rims aluminium nipples. carbon rims brass nipples. Worst combination is brass on aluminium. Copper and aluminium are a recipe for a caustic relationship. Brass contains 63% copper. Aluminium will always corrode and as such will be the sacrificial anode in any relationship. 

[David Marshall]

Aluminium nipples are the most common because it's a cheaper material to buy and work as well as a lighter material than stainless or brass. Brass is cheap to work but more expensive as a raw material than stainless. The best combination would be aluminium rims aluminium nipples. carbon rims brass nipples. Worst combination is brass on aluminium. Copper and aluminium are a recipe for a caustic relationship. Brass contains 63% copper. Aluminium will always corrode and as such will be the sacrificial anode in any relationship. 

I agree but disagree!  Failure on aluminium rim/aluminium nipple wheels is invariably the nipple so it must be a reaction between the spoke and the nipple.  I feel that with an aluminium rim/brass nipple combination the problem will take years to deteriorate to the same extent.

[SwissVan]

I had to respoke a second wheelset this week as a result of the chemical reaction between alu spoke nipples and carbon rims.

 

Has anybody else had a similar experience?

 

This is caused by the catalytic reaction between the alu nipples and the carbon rims facilitated by the presence of salt water (I live in CT). Considering that a large portion of the population globally live at the coast, does this point to a design flaw?

 

https://en.m.wikipedia.org/wiki/Galvanic_corrosion?wprov=sfla1

 

Sent from my SM-T561 using Tapatalk

Not a design flaw imo

What's the first or second thing you look for when buying bicycle wheels?

 

GRAMS.....WEIGHT of the part

 

Manufacturer can design bullet proof and more corrosion resistant wheels easy... but then they would not be sell as well because of the weight...and price

[Man with no name]

Not a design flaw imo

What's the first or second thing you look for when buying bicycle wheels?

 

GRAMS.....WEIGHT of the part

 

Manufacturer can design bullet proof and more corrosion resistant wheels easy... but then they would not be sell as well because of the weight...and price

That's a matter of perspective I guess. I prefer durability over weight, but feel equally scizo because I bought these wheels for their weight! Lesson learnt!

 

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[Plentipotential]

I agree but disagree!  Failure on aluminium rim/aluminium nipple wheels is invariably the nipple so it must be a reaction between the spoke and the nipple.  I feel that with an aluminium rim/brass nipple combination the problem will take years to deteriorate to the same extent.

 

Corrosion is between the aluminium rim and brass nipple not the spoke, unless the spoke is stainless steel.

[JXV]

I had to respoke a second wheelset this week as a result of the chemical reaction between alu spoke nipples and carbon rims.

 

Has anybody else had a similar experience?

 

This is caused by the catalytic reaction between the alu nipples and the carbon rims facilitated by the presence of salt water (I live in CT). Considering that a large portion of the population globally live at the coast, does this point to a design flaw?

 

https://en.m.wikipedia.org/wiki/Galvanic_corrosion?wprov=sfla1

 

Sent from my SM-T561 using Tapatalk

Its a galvanic reaction, not catalytic.

 

Caused by dissimilar metals simultaneously in contact with each other and with a body electrolyte. One metal will usually be severely corroded while nothing happens to the other.

Since it is conductive and can react, carbon fibre can act as a 'metal' for purposes of a galvanic couple. Batteries are probably the most ubiquitous examples of a galvanic couple in action.

 

The term electrolyte means basically any liquid that can transport an electric current - so, water, sea water, vinegar, blood, battery acid etc are all potential electrolytes. The stronger the concentration of salts in the liquid, the more effective it is as an electrolyte. This is why sea water is more corrosive than freash water.

 

There is a thing called the 'galvanic series' which is a list of galvanically active materials (nearly all metals) ranked in order of half-cell potential (reactivity). The further apart two materials are in this series, the more likely that the more reactive one will be corroded when it is used in simultaneous contact with the other and an electrolyte.

 

So.....how to prevent or reduce galvanic corrosion?

 

1) break the electrical circuit - by insulating the two metals from one another with a non conductive material like plastic or by insulating one or both from contact with the electrolyte (e.g. paint).

2) remove electrolyte - keep the metals dry....always

3) if two metals will contact each other in a wet environment, choose metals that are close to each other in the galvanic series where possible ( eg copper and brass will do better than a combination of alu and stainless steel.)

4) Dilute the electrolyte with fresh water

5) coat parts in moisture repellent coatings such as grease, oil, paint.

6) use a sacrificial anode ( attach a body of much more reactive metal - it will corrode preferentially - common on ships and submerged metal structures)

7) use impressed current to hold the part needing protection at a lower voltage relative to others. ( pipelines and railways are often protected this way)

 

Ok that's the lecture....now what can you do with your wheels.....?

 

A) keep them away from sea water and sea spray

B) dry immediately after washing and wash less frequently

C) use brass nipples rather than alu. It's closer to carbon in the galvanic series.

D) store indoors away from salty/ humid air

 

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[Christie]

Are these Campagnolo rims? Ive got a friend that has this problem on a Borat wheelset

[Man with no name]

Are these Campagnolo rims? Ive got a friend that has this problem on a Borat wheelset

Funny ????????????

 

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[Man with no name]

Its a galvanic reaction, not catalytic.

 

Caused by dissimilar metals simultaneously in contact with each other and with a body electrolyte. One metal will usually be severely corroded while nothing happens to the other.

Since it is conductive and can react, carbon fibre can act as a 'metal' for purposes of a galvanic couple. Batteries are probably the most ubiquitous examples of a galvanic couple in action.

 

The term electrolyte means basically any liquid that can transport an electric current - so, water, sea water, vinegar, blood, battery acid etc are all potential electrolytes. The stronger the concentration of salts in the liquid, the more effective it is as an electrolyte. This is why sea water is more corrosive than freash water.

 

There is a thing called the 'galvanic series' which is a list of galvanically active materials (nearly all metals) ranked in order of half-cell potential (reactivity). The further apart two materials are in this series, the more likely that the more reactive one will be corroded when it is used in simultaneous contact with the other and an electrolyte.

 

So.....how to prevent or reduce galvanic corrosion?

 

1) break the electrical circuit - by insulating the two metals from one another with a non conductive material like plastic or by insulating one or both from contact with the electrolyte (e.g. paint).

2) remove electrolyte - keep the metals dry....always

3) if two metals will contact each other in a wet environment, choose metals that are close to each other in the galvanic series where possible ( eg copper and brass will do better than a combination of alu and stainless steel.)

4) Dilute the electrolyte with fresh water

5) coat parts in moisture repellent coatings such as grease, oil, paint.

6) use a sacrificial anode ( attach a body of much more reactive metal - it will corrode preferentially - common on ships and submerged metal structures)

7) use impressed current to hold the part needing protection at a lower voltage relative to others. ( pipelines and railways are often protected this way)

 

Ok that's the lecture....now what can you do with your wheels.....?

 

A) keep them away from sea water and sea spray

B) dry immediately after washing and wash less frequently

C) use brass nipples rather than alu. It's closer to carbon in the galvanic series.

D) store indoors away from salty/ humid air

 

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Thanks v much. Very good advice but practically almost impossible. Will try though

 

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[Christie]

Funny ????????????

 

 

My Dura-Ace C24s had drainage holes so that water could not get trapped inside the rim

[BaGearA]

Its a galvanic reaction, not catalytic.

 

Caused by dissimilar metals simultaneously in contact with each other and with a body electrolyte. One metal will usually be severely corroded while nothing happens to the other.

Since it is conductive and can react, carbon fibre can act as a 'metal' for purposes of a galvanic couple. Batteries are probably the most ubiquitous examples of a galvanic couple in action.

 

The term electrolyte means basically any liquid that can transport an electric current - so, water, sea water, vinegar, blood, battery acid etc are all potential electrolytes. The stronger the concentration of salts in the liquid, the more effective it is as an electrolyte. This is why sea water is more corrosive than freash water.

 

There is a thing called the 'galvanic series' which is a list of galvanically active materials (nearly all metals) ranked in order of half-cell potential (reactivity). The further apart two materials are in this series, the more likely that the more reactive one will be corroded when it is used in simultaneous contact with the other and an electrolyte.

 

So.....how to prevent or reduce galvanic corrosion?

 

1) break the electrical circuit - by insulating the two metals from one another with a non conductive material like plastic or by insulating one or both from contact with the electrolyte (e.g. paint).

2) remove electrolyte - keep the metals dry....always

3) if two metals will contact each other in a wet environment, choose metals that are close to each other in the galvanic series where possible ( eg copper and brass will do better than a combination of alu and stainless steel.)

4) Dilute the electrolyte with fresh water

5) coat parts in moisture repellent coatings such as grease, oil, paint.

6) use a sacrificial anode ( attach a body of much more reactive metal - it will corrode preferentially - common on ships and submerged metal structures)

7) use impressed current to hold the part needing protection at a lower voltage relative to others. ( pipelines and railways are often protected this way)

 

Ok that's the lecture....now what can you do with your wheels.....?

 

A) keep them away from sea water and sea spray

B) dry immediately after washing and wash less frequently

C) use brass nipples rather than alu. It's closer to carbon in the galvanic series.

D) store indoors away from salty/ humid air

 

Sent from my SM-G935F using Tapatalk

Thank you Sir , Now I have learned something new today