Corrosion (T)

• What is the definition of corrosion?

  Destruction of materials by chemical reactions
• What is a common example of corrosion?

  Rusting
• To which metals does rusting apply?

  Iron and alloys of iron
• What term should be used for metals other than iron when they corrode?

  Corroding
• What is the setup of the first test tube in the rusting experiment?

  Iron nail in distilled water, open to air
• What is the setup of the second test tube in the rusting experiment?

  Iron nail in boiled distilled water, covered with oil
• What is the setup of the third test tube in the rusting experiment?

  Calcium chloride powder, sealed to prevent moisture
• What were the results of the rusting experiment?

  Rust formed in test tube one only
• What does rusting require to occur?

  Both air and water
• How can corrosion be prevented?

  By using a barrier between materials and environment
• What are some methods to create a barrier against corrosion?

  Grease, paint, or electroplating
• What happens to aluminum when it reacts with oxygen?

  Forms a protective layer of aluminum oxide
• What is galvanizing?

  Coating metal with zinc to prevent corrosion
• What is sacrificial protection?

  Using a more reactive metal to prevent corrosion
• Why do zinc bars get replaced on a ship?

  Because they corrode instead of iron
• What is the expected frequency of replacing zinc bars on a ship?

  Every couple of years
• What are the conditions required for rusting?

  • Presence of air
  • Presence of water
• What are the methods to prevent corrosion?

  1. Use of barriers (grease, paint)
  2. Electroplating
  3. Galvanizing (zinc coating)
  4. Sacrificial protection (more reactive metal)