Homework C

Question 1

3 basic steps for corrosion treatment :

Answer 1

remove as much corrosion as possible
neutralize residual material
restore protective surface film

Question 2

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?

Answer 2

retreat/alodine

Question 3

Battery acid from a lead-acid battery is neutralized with a solution of [1]

Answer 3

bicarbonate of soda and water

Question 4

A protective oxide film may be deposited on an aluminum alloy materials by
which 2 methods?

Answer 4

anodizing
alodizing

Question 5

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

Answer 5

water

Question 6

Magnesium __ naturally form a protective oxide coating on it surface.

Answer 6

does

Question 7

Clad aluminum is protected from corrosion by a layer of ______________ on the
aluminum alloy core.

Answer 7

pure aluminum

Question 8

A spot weld seam may be inspected for corrosion by placing a [1] over the seam
and checking it for any indication of bulging between the spots

Answer 8

straight edge

Question 9

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

Answer 9

Air
moisture

Question 10

After the corrosion has been mechanically removed from an aluminum alloy, the
surface should be neutralized by treating it with a 5% solution of [1]

Answer 10

chromatic acid

Question 11

Before joining dissimilar metals they are prepared by spraying two coats of zinc
chromate primer and placing a strip of pressure sensitive vinyl tape between the
surface before they are assembled.

Answer 11

zinc chromate
pressure sensitive vinyl

Question 12

Welding flux on aluminum alloy may be removed by washing it with [1]

Answer 12

hot water

Question 13

Battery acid from a nickel-cadmium battery is neutralized with a solution of [1]

Answer 13

boric acid

Question 14

Corrosion must never be removed from aluminum with steel brushes or with [1]

Answer 14

steel wool

Question 15

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

Answer 15

zinc

Question 16

Welded steel tube engine mounts are protected from internal corrosion by
coating the inside of the tubing with hot [1].

Answer 16

linseed oil

Question 17

Stiff [1] brushes can be used to remove corrosion from magnesium surfaces.

Answer 17

non-metallic

Question 18

We do not use wire brushes on [1] because they cause minute scratches that can
produce stress and weaken the part.

Answer 18

highly stressed steel

Question 19

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

Answer 19

sacrificial

Question 20

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

Answer 20

zinc chromate
wash primer
epoxy primer