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Service Wide Exam > Corrosion > Flashcards

Corrosion Flashcards

0
Q

Corrosion that occurs when different metals are in contact with each other and an electrolyte. Recognizable by the presence of a buildup of corrosion deposits at the joints between metals

A

Galvanic

NAVAIR 01-1A-509-1 3-6

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1
Q

Pitting

A

most common on stainless steels but common on aluminum and magnesium alloys, white or grey powdery deposits, similar to dust which botch the surface, tiny pits or holes can be seen on the surface

NAVAIR 01-1A-509-1 3-6,7

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2
Q

Intergranular

A

grain boundaries of the metals(cross sections), high strength aluminum alloys are most susceptible

NAVAIR 01-1A-509-1 3-7

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3
Q

Exfoliation

A

An advanced form of intergranular, surface grains of the metal are lifted up by the force of expanding corrosion, lifting up or swelling is visible evidence of exfoliation corrosion

NAVAIR 01-1A-509-1 3-7

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4
Q

Crevice

A

electrolyte inside crevice contains less O2 and more metal ions than electrolyte just outside the crevice(stagnant solution has pooled). This is common around gasket surfaces, lap joints, and under bolt or rivet heads

NAVAIR 01-1A-509-1 3-7

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5
Q

Stress corrosion cracking

A

Intergranular or transgranular cracking of a metal caused by the combined effects of constant tensile stress and corrosion.

NAVAIR 01-1A-509-1 3-10

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6
Q

Fillform

A

O2 concentration cell corrosion or crevice corrosion occurs on metal surfaces having a thin organic coating system, wormlike trace of corrosion beneath the paint film. Starts at breaks in the coasting system such as scratches and cracks around fasteners and seams, Affected by humidity, keep aircraft below 65%

NAVAIR 01-1A-509-1 3-9,10

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7
Q

What are the two most important factors of preventing corrosion and the only which can be controlled by field personnel

A
  1. the removal of the electrolyte
  2. application of protective coatings

NAVAIR 01-1A-509-1 2-1

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8
Q

Iron in the presence of moisture and air will return to its natural state which is what

A

iron oxide rust

NAVAIR 01-1A-509-1 3-1

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9
Q

Aluminum and magnesium form corrosion products that are what

A

White oxides or hydroxides

NAVAIR 01-1A-509-1 3-1

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10
Q

What is the most common type of corrosion and is also can be the most effectively treated by maintenance personal is what

A

Electrochemical corrosion

NAVAIR 01-1A-509-1 3-1

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11
Q

What type of corrosion commonly occurs at the edge of aircraft skin sections or next to countersunk fasteners

A

Exfoliation

NAVAIR 01-1A-509-1 3-3

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12
Q

What type of corrosion happens with a flashlight battery

A

Galvanic

NAVAIR 01-1A-509-1 3-3

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13
Q

What metal has the highest potential to corrode

A

Lithium

NAVAIR 01-1A-509-1 3-4

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14
Q

The most common type of corrosion, resulting from direct chemical attack on a metal surface that proceeds uniformly over the entire exposed surface. May show up as general dulling, etching, rough, frosted.

A

Uniform surface corrosion

NAVAIR 01-1A-509-1 3-6

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15
Q

This type of corrosion most often occurs on extruded sections of metal and is found primarily in aluminum sheet around steel fasteners.

A

Exfoliation

NAVAIR 01-1A-509-1 3-7

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16
Q

This corrosion is characterized by grooves, gullies, waves, rounded holes and/or valleys in the metal surface.

A

Erosion

NAVAIR 01-1A-509-1 3-10

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17
Q

What can cause stress corrosion

A

Welding, cold working, forming, and heat treatment operations

NAVAIR 01-1A-509-1 3-10

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18
Q

Corrosion occurs at contact areas between materials under load subject to repeated vibration, has a general appearance of galling, in which chunks of metal are torn from the surface. Occurs commonly in landing gear component attachment areas or engine blade roots

A

Fretting

NAVAIR 01-1A-509-1 3-11

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19
Q

Also called high temperature oxidation, absence of water can occur at high temperatures such as those found in turbine engine combusters, turbine sections, and afterburners

A

Hot Corrosion

NAVAIR 01-1A-509-1 3-11

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20
Q

What type of corrosion attacks aluminum alloy

A

surface pitting, intergranular, exfoliation, stress, and fretting- white to gray powder

NAVAIR 01-1A-509-1 3-13

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21
Q

What type of corrosion attacks magnesium alloy

A

Pitting- white powdery, snowlike mounds, and white spots on surface

NAVAIR 01-1A-509-1 3-13

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22
Q

How does corrosion usually present

A

Chalky white powder or green discoloration

CGTO PG-85-00-310-A 7-91

23
Q

This type of corrosion is similar to intergranular corrosion except the corrosion follows grain boundaries and large chunks fall out. Extrusions can be susceptible where grain boundaries are stretched and/or rough surfaces occur during the
extruding process

A

exfoliating

PG 85-00-60 ENCL 1

24
Q

A common form of corrosion
on aluminum and magnesium alloys is _____ corrosion. It is first noticeable as a white or gray powdery deposit, similar
to dust, which blotches the surface.
When the deposit is cleaned away, tiny pits or holes can be seen in the surface. _____ can be particularly damaging on high strength steels such as landing gear

A

Pitting

PG 85-00-60 ENCL 1

25
Q

_____ corrosion occurs
when two dissimilar metals make
electrical contact in the presence of
an electrolyte. The most active metals (those which tend to lose their electrons easily), such as magnesium and aluminum, corrode easily

A

Galvanic

PG 85-00-60 ENCL 1

26
Q

_____ corrosion refers to corrosion occurring in confined spaces to which the access of the working fluid from the environment is limited. The presence of even minute spaces between metal components provides an ideal location for the intrusion of an electrolyte

A

Joint or Crevice

PG 85-00-60 ENCL 1

27
Q

Most alloys are made
up entirely of small crystal line regions, called grains. _____ corrosion is an attack along the boundaries of these grains. The grain boundaries differ, from a chemical point of view, from
the metal within the grain center. The grain boundary and the grain center can react with each other as a node and cathode when they are in contact with an electrolyte

A

Intergranular

PG 85-00-60 ENCL 1

28
Q

A uniform, regular removal of metal from the surface

A

Uniform or Surface Corrosion

PG 85-00-60 ENCL 1

29
Q

The rate at which corrosion proceeds maybe accelerated by a number of mechanical factors. Stress on aircraft parts maybe residual within the part as a result of externally applied cyclic loading or as a result of the production process. Corrosion fatigue is caused by the combined effects of cyclic stress and corrosion.
No metal is immune to some reduction in its resistance to cyclic stressing if the metal is in a corrosive environment. Fracture of a metal part due to fatigue corrosion generally occurs at a stress
level far below the fatigue limit. The
amount of external corrosion is a poor indicator of the strength of the part. For this reason, corrosion protection of all parts subject to alternating stresses is particularly important, even in environments which are only mildly corrosive.

_____ is where the internal stresses (residual stresses) vary across a section so that when they are loaded with additional outside forces, the grain boundaries at the surface start to break

A

Stress Corrosion

Stress Corrosion cracking

PG 85-00-60 ENCL 1

30
Q

Damage can occur at the
interface of two highly loaded surfaces which are not designed to move against each other. The most common type of _____ corrosion is caused by vibration. The protective film on the metal surfaces is removed by the rubbing action and exposes fresh, active metal to the corrosive action of the atmosphere. Often the by product is most noticeable on the surface and
is referred to as a working or smoking fastener/rivet, identifiable by the black soot like appearance around the fastener head and often trailing away

A

Fretting

PG 85-00-60 ENCL 1

31
Q

This form of attack occurs
on metallic surfaces having an organic coating as its protective basis. It is characterized by a snake like pattern of corrosive deterioration that forms
beneath painted surfaces. _____
attack tends to occur when relative
humidity is high (78 to 90%) and surface conditions are slightly acidic

A

Filliform

PG 85-00-60 ENCL 1

32
Q

_____ attacks on metallic surfaces include the
actions of bacteria, fungi, and
molds. _____ occur nearly
everywhere. Those organisms causing the greatest corrosion problems are bacteria and fungi. Wet wings with fuel can be a common location for microbial
attacks, particularly if insufficient Fuel System Icing Inhibitor (FSII), which contains microbial inhibitors to combat this type of corrosive attack, is used

A

Micro-Organism or Microbial
Corrosion

PG 85-00-60 ENCL 1

33
Q

The Logistics Management Institute (LMI) estimated the annual corrosion cost for Coast Guard aviation alone to be nearly

A

$100 million

1-1

34
Q

The M13020.1 limits the time of deferring a corrosion discrepancy to how long

A

30 days

2-3 note

35
Q

Who can approve the deferring of a corrosion discrepancy more than 30 days

A

EO

2-3 note

36
Q

How often does the EO review the air station corrosion control plan

A

annually

2-3

37
Q

Who designates a UCPM for each air station airframe type

A

EO

2-3

38
Q

Where can you find a sample UCPM designation letter

A

PG 85-00-60 Enclosure 3

2-3

39
Q

UCPM must be what rank and rate

A

AMT1 or above

2-3

40
Q

How long shall a member remain as the UCPM

A

2 years, unit permitting

2-4

41
Q

How often shall the corrosion master plan be reviewed

A

annually

3-1

42
Q

What shall detail the duties and responsibilities of the UCPM as per the EO

A

air station corrosion control plan

4-1

43
Q

For new approved chemicals, how do you submit changes to the ACL and applicable MPCs

A

CG-22

4-3

44
Q

What is the process of removing atmospheric moisture from a given space

A

dehumidification

4-3

45
Q

What is the ratio of water vapor in the air to how much water vapor the air can hold at a given temperature

A

relative humidity

4-3

46
Q

Using DH to reduce the humidity levels below on average _____, the electrolyte path that is required to generate corrosion is effectively eliminated. When the relative humidity level is above _____, corrosion readily begins to accelerate

A

40%

60%

4-4

47
Q

For avionics components, similar studies have shown reducing humidity levels below _____ RH
significantly improves Mean Time Between Failure (MTBF) rates

A

50%

4-5

48
Q

Running the DH system for how long will reduce the RH to levels between 30-40% RH could be achieved.

A

One hour or less

4-6

49
Q

How long does it take to remove and install the DH system

A

Five minutes or less to install and remove the DH units was possible

4-6

50
Q

Running the DH system a minimum of 8 hours per day average sustaining an average RH of _____ could be achieved

A

40 %

4-6

51
Q

Paint discrepancies shall not be deferred past how many days without approval from who

A

30 days

EO

4-11

52
Q

For touch up painting the paint should cover how much of the area

A

1 inch overlap

4-12

53
Q

The results of the semiannual water testing must be filed with the QA office for how long

A

2 year minimum

4-12

54
Q

Aircraft wash racks should have water available at what temperature for aircraft washing

A

120-140 F

4-12

55
Q

This AFTO states that“ all aircraft stationed within 1.25 miles (2km) of saltwater require a CWR
at least once every _____ days unless washed first

A

15 days

4-13

Service Wide Exam (40 decks)

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