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Water
Industry Corrosion |
Corrosion Process
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The
natural corrosion of steel involves the formation of an electrochemical
corrosion cell. This cell is made up of an anode and a cathode,
typically at two different sites on the steel component, an electrolyte, and
an electrical connection between the anode and cathode. |
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The chemical
reaction at the steel anode site is the oxidation of the metal, followed
generally by oxide or hydroxide formation: |
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Fe
® Fe++
+ 2 e-
(1)
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Fe++ +
2OH-®
Fe(OH)2
(2)
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At the same time, an
electrochemical reaction, generally the reduction of atmospheric oxygen,
occurs at the steel cathode site: |
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½O2
+ H2O + 2e- ®
2OH-
(3)
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Course
Outline
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The Corrosion Process
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1. Definition |
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2. Costs of Corrosion |
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3. Expressions for Corrosion Rate |
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4. The Corrosion Cell |
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5. Reference Electrodes
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6. The Galvanic Series |
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7. Importance of the Cathode
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8. The Rusting of Steel
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9. Problems
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10.
Practical and Demonstrations |
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Electrochemistry of Corrosion
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1. Electrode Potentials
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2. Oxidation-Reduction Potentials
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3. The Nernst Equation
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4. Pourbaix Diagrams
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5. Problems
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Corrosion Kinetics
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1. Faraday's
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2. Polarization
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3. Types of Polarization
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4. The Nature of Passivity
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Failure Case
Studies
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