Chapter 2 Corrosion Flashcards

1
Q

Define corrosion

A

The deterioration of a material, usually a metal, that results from a reaction with its environment

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2
Q

What is passivation?

A

A layer of oxides formed on the surface of a metal that provides corrosion protection. Stainless steel for example.

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3
Q

What are the elements of a corrosion cell?

A

Anode, Cathode, Metallic Pathway, Electrolyte

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4
Q

Describe what happens at the anode

A

The metal dissolves into the electrolyte

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5
Q

What is the function of the electrolyte?

A

It allows the passage of ions to conect the corrosion cell

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6
Q

What is the function of the metallic pathway?

A

It allows the flow of electrons to connect the corrosion cell

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7
Q

What is the galvanic series?

A

A listing of metals in order of reactivity (more or less noble) in seawater at 25*C

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8
Q

The general rules of galvanic corrosion are:

A

The less noble ( or more reacitive ) metal when connected to a more noble ( or less reactive metal ) will corrode preferentially

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9
Q

Name at least five factors that affect the rate of corrosion.

A

Oxygen, Temperature, Chemical Salts, Humidity (wetness), Pollutants & Acid Gases

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10
Q

General corrosion is:

A

Results in a relatively uniform loss of material over the entire surface.
Results in a general thinning of the affected surface.
Relatively east to inspect.
Does no cause catastrophic failures.

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11
Q

Localized corrosion is:

A

Typically Pitting and Crevice Corrosion. It is typically of the most concern as damage is concentrated and loss of integrity or structural failure can result.

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12
Q

List some of the common tools/methods used for corrosion control

A

Design, Inhibitors, Material selection, Cathodic protection, Protective coatings, Alteration of the environment

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