chapter 2 corrosion as related to coatings

Question 1

_______ is a destruction of a substance (usually metal) or its properties because of a reaction with its _______.

Answer 1

corrosion

environment

Question 2

The _______ of the material, as well as the material itself, can __________

Answer 2

properties

deteriorate

Question 3

_______ occurs when the _______ of a coating disintegrates from the exposed surface through the depth of the coating until the substrate is exposed.

Answer 3

chalking

binder

Question 4

__________ after it has been reduced from iron ores, is ____________ unstable.

Answer 4

elemental iron

thermodynamically

Question 5

In order to change iron from an oxidized state (iron ore) to that of a metal, it is necessary to force a large amount of _______ into the system

Answer 5

energy

Question 6

The fundamental laws of nature governing the conservation of energy require that, in time, the energy balance must be ______ by ________ the unstable metal to its _________ state.

Answer 6

restored
returning
oxidized

Question 7

When a metal displaces another in a chemical reaction, this is known as a ________ ________ reaction.

Answer 7

double displacement

Question 8

The four items required for the corrosion of metals in an electrochemical process are:___________ ___________ ___________ ____________ contact t or an ______ circuit between the ______ and the _______ . these four elements constitute what is known as a ___________ cell.

Answer 8

anode cathode electrolyte
external external
anode cathode

corrosion cell

Question 9

________ is a fifth element, which is also generally required in the corrosion process.

Answer 9

Oxygen

Question 10

Ions can be defined as atoms or groups of atoms that have either ______ or ________ one or more electrons from their outer ________ _____.

Answer 10

taken surrendered

electron rings.

Question 11

positively charged ions (cations) are attracted toward the _______: negatively charged ions (anions) are attracted to the __________

Answer 11

Cation

Anion

Question 12

Iron is a neutral atom when it is in its _________ form, but becomes and _____ when it loses two electrons therefore becomes _____ charged.

Answer 12

metallic
ion
positively

Question 13

chemical formula for the ionization of a metal

Answer 13

Fe —-H2O—> Fe++ + 2e-

Question 14

The ____ is the area where the metal goes into ____ and metal loss takes place.

Answer 14

Anode

Solution

Question 15

The ______ reaction cannot occur at a higher rate than the corresponding electrons can be accommodated by the _________ reaction.

Answer 15

Anodic

Cathodic

Question 16

The _________ is the solution that is on , surrounds, or covers the metal. T^he ______ of the solution on the metal surface is the key to the speed of the corrosion process.

Answer 16

electrolyte

conductivity

Question 17

corrosion cells form ______ in pure water

Answer 17

slowly

Question 18

corrosion cells form ________ in seawater because it is almost 100% ionized and is a very good _________.

Answer 18

readily

conductor

Question 19

When the anode and the cathode are on the same metal surface, the metal surface acts as the ________ _________ .

Answer 19

external circuit

Question 20

In the case of two metals, there must be an ________ _______ in order for the corrosion process to take place

Answer 20

external connection

Question 21

While the corrosion may begin with the presence of only the four factors, without _______ the process soon slows down or stops altogether .

Answer 21

Oxygen

Question 22

The flow of electrical current runs from the _______ through the solution to the__________

Answer 22

anode cathode

Question 23

The ________ is used to describe the area of metal surface to which the current flows from the solution and then returns by way of the external circuit to the ________

Answer 23

Cathode

anode

Question 24

electrons flow from the _________ to the _________ through the _______ circuit

Answer 24

anode to the cathode

electrical

Question 25

oxidation can mean either the _______ or iron, or the development of ______ ______ on aluminum or zinc

Answer 25

rusting

white oxide

Question 26

The movement of iron from its metal form to the ion form is called _______. it occurs at the __________

Answer 26

oxidation

anode

Question 27

the chemical formula for oxidation of iron

Answer 27

Fe Fe++ + 2e-

Question 28

When the movement proceeds in the opposite direction, adding ______ to the _________ iron, the reaction occurs in the direction of the iron as metal and is referred to as __________

Answer 28

electron to the ionized

reduction