Cleaning and corrosion

Inside the nucleus of an atom, the basic unit of a chemical element, you will find what components?

protons and neutrons

In scientific terms, how would you describe electrical charges?

positive, negative, and neutral

When an atom contains more electrons than protons, what type of ion is it called?

negative

A metal undergoes what kind of action when it transforms into a chemical salt through corrosion?

electric chemical

In an electrochemical reaction, which part is subject to deterioration?

Anode

What three conditions must be present for corrosion to form in a material?

potential difference, conductive path, and electrolight

What kind of surface film forms on aluminum alloys to protect them from oxidation?

aluminum oxide

In what types of areas does metallic ion concentration cell corrosion typically develop?

open areas

Under which type of paint system does filiform corrosion most often appear?

polyurethane

Although both materials corrode, aluminum alloys are especially susceptible to what?

alkali

Salt solutions are particularly aggressive toward which material?

magnesium

What is the name of the electrochemical process that returns metal to a weak chemical compound resembling its natural state?

corrosion

Corrosion is divided into two main classification— what are they?

direct and electrochemical attack

When does a direct chemical attack occur?

direct exposure to caustic liquids

What is the primary source of corrosion found in aircraft?

salt

Most metals that are ___ are not suitable for use in aircraft

pure

Under what conditions does electrochemical corrosion accelerate?

hot and humid conditions

How can oil and grease influence the development and spread of corrosion?

It collects and holds salt, moisture, etc.

What type of corrosion occurs when a bare surface is exposed to caustic substance?

direct chemical 

Which type of corrosion requires an anode, a cathode, and an electrolyte to occur?

electro chemical

Which form of corrosion creates a wormlike pattern beneath the paint?

filiform

Which highly destructive form of corrosion often targets aluminum and magnesium alloys?

pitting

Which type of corrosion affects only alloys?

Intergranual

What occurs when two dissimilar metals come into electrical contact in the presence of an electrolyte?

Galvanic

Can you identify the areas most prone to corrosion?*

battery compartments, engine compartments, landing gear

What is the ideal length to depth ratio for forming smooth, blended dish-outs?

20 to 1

Ruse is a form of corrosion that affects which type of materials?

ferrous 

Among the metals used in aircraft construction, which one is the most chemically active?

magnessium

Which metal is most commonly used in aircraft construction?

aluminum

What surface treatment is most widely applied to nonclad aluminum alloy surfaces?

Anodized

How would you define a direct chemical attack?

direct exposure

Which type of corrosion involves a chemical reaction with oxygen and is considered dry corrosion?

oxidation

What do you call corrosion that spreads across the surface without forming pits?

uniform

Corrosion that appears in the form of small “pockets” is known as what?

pitting

What is the name of the advanced intergranual corrosion that causes flaking or layered damage?

exfoliation 

Which type of corrosion results from rubbing between two tightly fitted parts?

fretting

Why should non-approved or ordinary cleaning compounds be avoided when washing aircraft?

hydrogen and embrittlement

Is it acceptable to use stiff wire brushes to remove corrosion from magnesium?

No

Can concentration cell corrosion occur at a joint between two metals of the same type?

Yes

Which five factors influence the development of corrosion?

moisture, heat, salt, microbial growth, and foreign materials

Steel brushes and what other item should never be used to clean corrosion from aluminum?

steel wool

How is internal corrosion protection applied to welded steel tube engine mounts?

Hot linseed oil 

What protective layer is added to clad aluminum to shield the alloy core from corrosions?

pure aluminum

What is the recommended method for cleaning magnesium parts?

Washed, decarbonized, blasted

Out of all the materials used, which one is the most anodic?

Magnesium 

Among various materials, which one acts as the most cathodic?

Gold