Does dezincification always lead to dark red spots on brass?

  • Thread starter gomerpyle
  • Start date
In summary, dezincification is a common form of corrosion in brass that can occur due to exposure to water, acid, or salt. It can result in the appearance of dark red spots, and the greenish color of corrosion is usually due to the formation of verdigris, a mixture of different copper compounds. Dezincification can also cause brass to become porous, making it more susceptible to corrosion. Other factors, such as electrolytic corrosion and alloy composition, can also contribute to dezincification.
  • #1
gomerpyle
46
0
I have a brass part that is showing signs of corrosion, namely the appearance of dark red spots. Through research I've learned that this is probably caused by dezincification, which can occur after exposure to water, acid, or salt. My question is I have noticed brass corrosion also involves the formulation of copper carbonates from the copper oxidizing (green color). Is this simply a later stage of corrosion after dezincification has taken place, i.e.: once the zinc is selectively leached away then the copper is the only element left to react? So is it a fair assumption to assume dark red sports are simply an early stage of corrosion in brass?

OR, is the greenish color of corrosion the result of a different chemical reaction causing the copper to react and not the zinc? (EX, ammonia attacking brass causing copper to react and not zinc?)
 
Engineering news on Phys.org
  • #2
The greenish color is independent of the red rot (dezincification) you see.
 
  • #3
The green coloured corrosion is mostly verdigris . The actual composition of verdigris varies a lot . Usually it is a mixture of several different Copper compounds .

White coloured corrosion sometimes seen is mainly simple zinc compounds .

Dezincification causes the Brass to become porous . Sometimes areas of porosity become active sites for corrosion .

There is always the possibility of electrolytic corrosion when brass is in contact with ferrous metals in wet conditions .
 

1. What is dezincification of brass?

Dezincification of brass is a corrosion process that occurs when zinc is removed from the surface of brass alloys, leaving behind a porous copper structure. This can weaken the brass and cause it to fail over time.

2. How does dezincification of brass occur?

Dezincification of brass occurs due to a combination of chemical and electrochemical reactions. It typically happens in the presence of oxygen, water, and certain impurities in the brass alloy, such as sulfur and ammonia.

3. What are the effects of dezincification of brass?

The effects of dezincification of brass include changes in the physical and mechanical properties of the alloy, such as reduced strength and ductility. It can also lead to pitting and perforation of the brass, causing it to fail.

4. How can dezincification of brass be prevented?

Dezincification of brass can be prevented by using brass alloys that are resistant to dezincification, such as those with a low zinc content or the addition of other alloying elements, such as tin and aluminum. Proper design and maintenance of brass components can also help prevent dezincification.

5. Can dezincification of brass be reversed?

No, once dezincification of brass occurs, it cannot be reversed. It is a permanent degradation of the alloy and the affected brass components will need to be replaced. However, preventive measures can be taken to avoid dezincification in the first place.

Similar threads

Chemically regenerating my auto's catalytic converter?
    • Chemistry
Replies
16
Views
2K
What colors and attributes could alien flora & fauna have?
    • Sci-Fi Writing and World Building
Replies
15
Views
3K

Hot Threads

Recent Insights

Back
Top