Chapter 2: Corrosion Flashcards
What tools are used to control corrosion
- Design
- Inhibitors
- Material selection
- Cathodic protection
- Protective coatings
- Splash Zone Systems
- Alteration of the environment
Define corrosion
The deterioration of a substance, usually a metal from a reaction with its environment.
What is passivation?
A layer of oxides formed on the surface of a metal that provides corrosion protection. Stainless steel is an example
What are the elements of a corrosion cell?
- Anode
- Cathode
- Metallic Pathway (Return Path)
- Electrolyte
Describe what happens at the Anode?
The metal dissolves into the electrolyte
What is the function of the metallic pathway?
Allows the flow of electrons to connect to the corrosion cell
What are the galvanic series?
A listing of metals in order of reactivity (more or less noble) in seawater at 25 celsius
The general rules of galvanic corrosion are?
The less noble (or more reactive) metal when connected to a more noble (or less reactive metal) will corrode preferentially
Name the five most important factors that affect the rate of corrosion
- Humidity
- Oxygen
- Chemical Salts
- Pollutants
- Temperature
General corrosion is
- Results in a relatively uniform loss of material over the entire surface
- Results in a general thinning of the affected surface
- Relatively easy to inspect
- Does not cause catastrophic failures
Localized corrosion is
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
What is the function of the electrolyte
Allows the passage of ions to connect to the corrosion cell
