Corrosion 7

Question 1

• Occurs in the presence of a liquid containing ions.

Answer 1

Wet Corrosion

Question 2

Occurs at elevated temperatures above 400°C.

Answer 2

High- Temperature Corrosion

Question 3

high carbon-iron alloys containing silicon.

Answer 3

Cast Iron

Question 4

Contain 2% to 4% carbon and 1% to 3% silicon.
- Considered as the least expensive of the engineering metals.

Answer 4

Gray Cast Iron

Question 5

• all the carbon in the form of iron carbide.

Answer 5

White Cast Iron

Question 6

– high-temperature heat treatment of white iron of proper composition.
- The graphite forms as rosettes or clusters.

Answer 6

Malleable Cast Iron

Question 7

The graphite is present as nodules or spheroids as a result of a special treatment of the molten metal.

Answer 7

Ductile Cast Iron

Question 8

When the silicon content of gray cast iron is increase to 14%, it extremely becomes corrosion resistant to many environments.

Answer 8

High Silicon Cast Iron

Question 9

• Composed of up to 2.14% carbon.

Answer 9

Steels

Question 10

Contained at least 11% chromium.

Answer 10

Stainless Steels

Question 11

Can be hardened by heat treatment similar to ordinary steel.

Answer 11

Martensitic Stainless Steels

Question 12

Essentially nonmagnetic and cannot be hardened by heat treatment.
- Can only be hardened by cold working.

Answer 12

Austenitic Stainless Steels

Question 13

Cannot be hardened by heat treatment.
- Can only be hardened by cold working, just like Austenitic stainless steel.

Answer 13

Ferritic Stainless Steels

Question 14

Hardened and strengthened by solution-quenching.

Answer 14

Precipitation-hardened Stainless Steels

Question 15

is different from most other metals in that it combines corrosion resistance with high electrical and head conductivity, formability, machinability, and strength when alloyed.

Answer 15

Copper

Question 16

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.

Answer 16

Copper – zinc alloys

Question 17

Lightweight metal having good corrosion resistance to the atmosphere and most aqueous media.
- Aluminum corrosion can occur at Extreme pH (>8 and <4 pH)

Answer 17

ALUMINUM

Question 18

Has the lowest density of all structural metals (1.7g/cm3 vs steel with 7.85g/cm3)

Answer 18

MAGNESIUM

Question 19

Magnesium alloys are sought after for its high strength-to-weight ratio.

Answer 19

MAGNESIUM ALLOYS

Question 20

is ductile and tough mainly because of its face-centered cubic structure.

Answer 20

Pure nickel

Question 21

Consists of 10-30% copper and 70-90% nickel.

Answer 21

CUPRONICKELS

Question 22

Also known as Nichrome.

Answer 22

NICKEL-CHROMIUM ALLOYS

Question 23

It is a device used in an electrochemical cell for connecting its oxidation and reduction half cells wherein an inert electrolyte is used.

Answer 23

SALT BRIDGE

Question 24

lists elements and compounds in terms of how strongly they desire to pull electrons.

Answer 24

Standard Reduction Potential

Question 25

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.

Answer 25

Electrochemical Cell

Question 26

electrical energy is used to drive a non-spontaneous.
- electrical energy is used to drive a non-spontaneous.

Answer 26

ELECTROLYTIC CELL

Question 27

cells with two identical electrodes, each in contact with a solution of different composition.

Answer 27

Salt concentration cell