Corrosion Questions Flashcards
What ways are there to protect metal from corrosion?
surface coating of paint
surface coating of metal ie. alclad
introduction of certain elements into the base metal
corrosion resistant alloy
surface coating of a chemical conversion coating
moisture barriers like lubricants and protectants
Metal corrosion is the deterioration of the metal by 2 means. What are they?
Chemical
Electrochemical
galvanic corrosion
dissimilar metal corrosion
uniform surface
covering an entire surface general roughening
filiform
worm like appearance caused by improper wash primer
intergranular
attack along the grain boundaries from improper heat treating
exfoliation
advanced form of intergranular with flaking
stress
cracking from sustained tensile force and corrosive environment
fretting
matting surfaces have slight relative motion between them leaving fine debris
a smoking rivet is a sign of
fretting
oxidation
when metal is exposed to oxygen in the air
concentration cell
has 2 forms; oxygen and metallic ion
pitting
pockets of white or gray powder
There are two general classifications of corrosion.
direct chemical and spilled battery acid is an example of it.
direct chemical and electroplating is an example of it.
_____ ______ and _______ _______ ____ is an example of it.
direct chemical
spilled battery acid
What is needed for electrochemical attack to occur (3)
anode
cathode
electrolyte
Heat will speed up corrosion
True
Water is worse than salt water for corrosion
False
Florida weather is worse than Oklahoma
True
Soil and dust do not affect corrosion
False
Exhaust residue harms the paint but not corrosive
False
Welding flux is corrosive
True
Corrosion preventive maintenance includes the following: (9)
sealing against water
treatment of corrosion and touchup of paint
adequate cleaning
use of protective covers
periodic lubrication
wipe down of exposed critical areas
detailed inspection
clearing drain holes
draining of fuel cell sumps
What are some corrosion prone areas (7)
exhaust trail areas
bilge area
flap recesses
piano hinge
lavs and galleys
wheel well
battery compartment and vent openings
5 steps to corrosion removal
cleaning and stripping of the corroded area
restore protective surface
apply temporary or permanent coatings or paint finishes
removing as much of the corrosion as practicable
neutralizing residue
Ways to prevent dissimilar metal corrosion (involving contact) (5)
washers
grease
metal primer
sealant
aluminum tape
