Corrosion 7 Flashcards
- Occurs in the presence of a liquid containing ions.
Wet Corrosion
Occurs at elevated temperatures above 400°C.
High- Temperature Corrosion
high carbon-iron alloys containing silicon.
Cast Iron
Contain 2% to 4% carbon and 1% to 3% silicon.
- Considered as the least expensive of the engineering metals.
Gray Cast Iron
- all the carbon in the form of iron carbide.
White Cast Iron
– high-temperature heat treatment of white iron of proper composition.
- The graphite forms as rosettes or clusters.
Malleable Cast Iron
The graphite is present as nodules or spheroids as a result of a special treatment of the molten metal.
Ductile Cast Iron
When the silicon content of gray cast iron is increase to 14%, it extremely becomes corrosion resistant to many environments.
High Silicon Cast Iron
- Composed of up to 2.14% carbon.
Steels
Contained at least 11% chromium.
Stainless Steels
Can be hardened by heat treatment similar to ordinary steel.
Martensitic Stainless Steels
Essentially nonmagnetic and cannot be hardened by heat treatment.
- Can only be hardened by cold working.
Austenitic Stainless Steels
Cannot be hardened by heat treatment.
- Can only be hardened by cold working, just like Austenitic stainless steel.
Ferritic Stainless Steels
Hardened and strengthened by solution-quenching.
Precipitation-hardened Stainless Steels
is different from most other metals in that it combines corrosion resistance with high electrical and head conductivity, formability, machinability, and strength when alloyed.
Copper
have better physical properties than copper alone, and they are also more resistant to impingement attack; hence, brasses are used in preference to copper for condenser tubes.
Copper – zinc alloys
Lightweight metal having good corrosion resistance to the atmosphere and most aqueous media.
- Aluminum corrosion can occur at Extreme pH (>8 and <4 pH)
ALUMINUM
Has the lowest density of all structural metals (1.7g/cm3 vs steel with 7.85g/cm3)
MAGNESIUM
Magnesium alloys are sought after for its high strength-to-weight ratio.
MAGNESIUM ALLOYS
is ductile and tough mainly because of its face-centered cubic structure.
Pure nickel
Consists of 10-30% copper and 70-90% nickel.
CUPRONICKELS
Also known as Nichrome.
NICKEL-CHROMIUM ALLOYS
It is a device used in an electrochemical cell for connecting its oxidation and reduction half cells wherein an inert electrolyte is used.
SALT BRIDGE
lists elements and compounds in terms of how strongly they desire to pull electrons.
Standard Reduction Potential
a container in which chemical reactions produce electricity.
- The source of this energy is a spontaneous chemical reaction.
- The energy conversion is achieved by spontaneous.
- Electrons move, hence there is electricity.
Electrochemical Cell
electrical energy is used to drive a non-spontaneous.
- electrical energy is used to drive a non-spontaneous.
ELECTROLYTIC CELL
cells with two identical electrodes, each in contact with a solution of different composition.
Salt concentration cell
