1. CORROSION THEORY What Is Corrosion? Why Does Corrosion Happen?
How Does Corrosion Happen?
What are some different types?

2. To Make a Metal
Open Pit Butte, MT
Cu Copper Element
Copper Wire

3. What is Corrosion?
Deterioration of a metal as it reacts to its environment……… in an attempt to return to its natural state

4. Why Corrosion Happens Most Metals Not Stable in Normal Environments
They Want to Revert to a More Stable Condition

5. Terms Chemical Properties:
The way matter behaves when it is placed in contact with other kinds of matter
Physical Properties:
Color, Odor, Taste, Density, Freezing
Corrosion Cell:
Anode + Cathode + Metal Path + Electrolyte
Oxidation & Reduction:
1 Substance is being oxidized = Another substance is being reduced
Happens Simultaneously

6. How Do Metals Corrode? Direct Chemical Attack Electrochemical Reaction
Chemical Change + Production of Electrical Energy
Electrochemical Reaction

7. Direct Chemical Attack
Pitting Corrosion
Uniform Surface Corrosion
Localized Attacks
Salts Deposited From Coastal Waters
Urine Spray
Battery Acid Spillage
Gases Absorbed From Environment

8. Electrochemical Reaction
Cathode:
Passive Metal
Less Likely to Corrode Than Anode
Anode:
Active (weak) Metal
Electrolyte:
Any Liquid Path
Metal Path:
Conductor
Carries Flow of Electrons From Anode To Cathode
Usually Metal-to-Metal Contact – Fasteners in Metal

9. Galvanic Corrosion

10. Development All Corrosive Attacks Start on Surface
Uniform Surface Corrosion
Pitting
Galvanic
Protect Surface or Remove 1 Condition = Stop Corrosion
Penetrates Into Granular Structure
Results in Extensive Surface & Structural Damage
Intergranular Corrosion
Exfoliation
Stress Cracking
Fatigue

11. Destructive Corrosion
Exfoliation
Stress Cracking
Fatigue Failure

12. Corrosion & Rust Corrosion Video
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13. Corrosion Review Why Does Metal Corrode? What is Corrosion?
How Does Metal Corrode?
What are Some Different Kinds of Corrosion?