CORROSION Flashcards
It is the inevitable result when
metals are exposed to water, air etc.
NATURAL PROCESS
Corrosion
It is the deterioration of
the metal by chemical or electrochemical
attack.
Metal corrosion
This type of damage can take place
internally as well as on the surface.
Corrosion
2 general classifications of corrosion
Direct chemical attack
Electrochemical attack
It is an attack resulting
from a direct expo-sure of a bare surface to
caustic liquid or gaseous agents.
Direct chemical attack, or pure
chemical corrosion
It may be likened chemically to the electrolytic
reaction that takes place in electroplating,
anodizing, or in a dry cell battery.
Electrochemical attack
3 Main Groups of Metals
FERROUS METAL
NON-FERROUS METAL
ALLOY
10 Types of Corrosion
GALVANIC
CONCENTRATION CELL / CREVICE
OXIATION / DRY
FRETTING
STRESS
UNIFORM SURFACE
OXYGEN CONCENTRATION CELL
FILIFORM SURFACE
INTERGRANULAR
EXFOLIATION
It is type of corrosion occurs when along the grain boundaries and causes the material separate or delaminated.
INTERGRANULAR CORROSION
It is corrosion of metals in a metal-to-metal joint
Concentration cell corrosion, or CREVICE CORROSION
It occurs when oxygen in the air reacts with metal without the presence of a liquid.
Dry corrosion or OXIDATION
It is revealed by block or greyish brown powder or paste around the periphery of the faying surfaces.
FRETTING CORROSION
It occur when the metal is subjection to tensile stress in the presence of a corrosive environment.
STRESS CORROSION
It where an area of unprotected metal is exposed to an atmosphere containing battery fumes, exhaust gases, or industrial contaminants.
UNIFORM SURFACE CORROSION
type of corrosion is caused by the reaction of metallic surface with atmospheric contaminants.
UNIFORM SURFACE CORROSION
