test

We do not use wire brushes on (___) because they cause minute scratches that can produce stress and weaken the part.

Highly stressed steel

Welding flux on aluminum alloy may be removed by washing it with (______).

Hot water

Use of non-recommended cleaning compounds can result in a condition known as

Hydrogen embrittlement

All _____ should be avoided when using spray on cleaners and high pressure water rinse.

Electrical equipment

Metal corrosion is the deterioration of the metal by 2 means. What are they?

Electrochemical and Chemical

What is needed for electrochemical attack to occur

Electrolyte, Anode, and Cathode

(___) destruction of metal by mechanical action.

Erosion

Exhaust residue harms the paint but not corrosive

False

Soil and dust do not affect corrosion

False

Stiff wire brushes can be used to clean corrosion off of magnesium.

False

Water is worse than salt water for corrosion

False

You can use acetone to clean plastic

False

You do not have to lubricate after cleaning a hinge

False

(___) tends to corrode

Anode

In an electrochemical reaction, it is the (____) which will be eaten away.

Anode

A protective oxide film may be deposited on an aluminum alloy material by 2 methods

Anodizing and Alodizing

What is toxic and attacks acrylics and rubber products (__)

Aromatic naptha

Which of the following should not be used to clean acrylic plastics and rubber

Aromatic naptha

Chemical Treatments for Aluminum: This treatment is done by the manufacturer (___). This type of treatment is done by an A&P in the field (____)

1. Anodize 2. Alodine

There are two general classifications of corrosion. 1. (____) and (____) is an example of it. 2. (____) and (____) is an example of it.

1. direct chemical and Spilled batter acid 2. Electrochemical and electroplating

Aluminum alloy are protected from oxidation by the formation of a(n) (______) film on its surface

Aluminum Oxide

What are some corrosion prone areas

Bilge area, Exhaust trail areas, wheel well, Battery compartment and vent openings, Flap recesses, Lavs and Galleys, and Piano hinge

What should be used to neutralize a nickle-cadmium battery spill

Boric acid

(___) has less of a tenancy to corrode

Cathode

After the corrosion has been mechanically removed from an aluminum alloy, the surface should be neutralized by treating it with a 5% solution of (____).

Chromatic acid

5 steps to corrosion removal

Cleaning and stripping of the corroded area, Neutralzing residue, Apply temporary or permanent coatings or paint finishes, Removing as much of the corrosion as Practicable, and Restore protective surface .

(_____) attacks metal by chemical or electrochemical action.

Corrosion

An electrochemical process in which a metal is transformed into a chemical compound (returns to it's natural state) that generally has little strength is called

Corrosion

Formation of corrosion along the grain boundaries within an alloy is what type of corrosion?

Intergranular

Stubborn exhaust stains may be removed with a 1:2 mix of _____ and _____.

Kerosene and Varsol

Before joining dissimilar metals they are prepared by spraying two coats of (____) primer and placing a strip of (_____) tape between the surface before they are assembled.

Zinc chromate and Pressure sensitive vinyl

Welded steel tube engine mounts are protected from internal corrosion by coating the inside of the tubing with hot (___).

Linseed oil

(____) is particularly vulnerable to corrosive attack from salt solutions.

Magnesium

From the choices below, (____) is the most vulnerable metal to corrosive attack from salt solutions.

Magnesium

Ways to prevent dissimilar metal corrosion (involving contact)

Metal primer, Aluminum tape, Washers, Grease, and Sealant

Stiff [______] brushes can be used to remove corrosion from magnesium surfaces.

Non-metallic

When some of the electrolyte on a metal surface is partially confined (between faying surfaces or in a crevice), metal corrodes more rapidly. This type of corrosion is called (____) and is caused by (____) oxygen content of the electrolyte causing the metal to become anodic to other metal surfaces on the same part.

Oxygen concentration cell and too much/increased

Corrosion preventive maintenance includes the following:

Periodic lubrication, Sealing against water, Detailed inspection, Adequate cleaning, Clearing drain holes, Draining of fuel cell sumps, treatment of corrosion and touchup of paint, wipe down of exposed critical areas, use of protective covers

What type of corrosion is likely to occur in an alloy?

Pits and intergranular corrosion

Filiform corrosion usually forms under what paint system?

Polyurethane enamel

The basic unit of a chemical element is the atom. It is made up of a nucleus containing :

Protons and Electrons

Clad aluminum is protected from corrosion by a layer of (____) on the aluminum alloy core.

Pure Aluminum

The appearance of a powder on the surface of a piece of aluminum alloy that has been treated with Alodine is an indication of improper application. How do you correct this?

Retreat/Alodine

Cadmium plating protects steel parts from corrosion by the process of ____ corrosion.

Sacrificial

Galvanic corrosion is (____) with a large anode and smaller cathode surface area.

Slowed down

Prior to washing, openings for _____ and _____ lines should be plugged.

Static ports And Pitot tubes

Corrosion must never be removed from aluminum with steel brushes or with (____).

Steel wool

A spot weld seam may be inspected for corrosion by placing a [______] over the seam and checking it for any indication of bulging between the spots

Straight edge

Why don't noble metals like gold or platinum corrode?

They are chemically uncombined in their natural state

Galvanizing protects steel by covering it with a layer of ____.

Zinc

A few shavings from drilling won't cause corrosion

True

Florida weather is worse than Oklahoma

True

Heat will speed up corrosion

True

Welding flux is corrosive

True

You should only clean plastic while it is dry with a soft cloth

True

You should rinse plastic with fresh water before wipe.

True

Name 3 types of primers that may be used to protect a metal surface from corrosion and provide a good bond for the topcoat.

Wash primer, Epoxy primer, and Zinc Chromate

Microbial growth in the fuel tanks of a turbine power aircraft may cause corrosion by holding (___) against the aluminum alloy structure

Water

Plexiglas should be washed by hand with ____ and ____.

Water and Soap

A direct chemical attack is when:

a direct exposure of a surface to a caustic liquid happens.

Nickel- and Chrome- plating protect a steel part from corrosion by preventing ____ and ____ from reaching the surface of the metal.

air and moisture

What should be used to wipe down cleaned surfaces just before painting (____)

aliphatic naptha

While both materials will corrode metal, aluminum alloys are more vulnerable to (_____).

alkalis

Oxygen concentration cell corrosion forms in (____) areas.

closed

3 requirements for the formation of corrosion in a material

conductive path, electrical potential difference, and presence of electrolyte

Magnesium (___) naturally form a protective oxide coating on it surface.

does

Corrosion is a(n) (_____) action in which a metal is changed into a chemical salt.

electrochemical

Cleaning compounds used in the oxygen system are

isopropyl alcohol and anhydrous ethyl alcohol

If an atom has more electrons than protons, it is called a (______) ion

negative

Removal of corrosion from highly stressed steel can be removed using?

nonwoven abrasive pads, mild abrasive papers, fine buffing compounds

Corrosion occurs because

of the tendency for metals to return to tie natural state

Metallic ion concentration cell corrosion forms in (____) areas.

open

What 4 conditions must exist before corrosion can occur:

presence of a dissimilar conductive material which has less tendency to corrode, electrical contact between the anode and cathode, presence of a conductive liquid, and presence of a metal that will corrode

3 basic steps for corrosion treatment :

remove/neutralize/restore

Abrasive papers such as carborundum (silicon carbide), emery paper, or crocus cloth (____) be used on aluminum or magnesium

should not

What should be used to neutralize a lead-acid battery spill

sodium bicarbonate

Galvanic corrosion is (___) with a large cathode and smaller anode surface area.

sped up