11.2b Surface Protection

Question 1

what does surface protection do ?

Answer 1

prevent corrosion, damage from aggressive fluids and erosion protection

Question 2

why might a composite structure have surface protection?

Answer 2

protection from the effects of lightning strikes, UV rays and erosion

Question 3

what should be considered when choosing the type of surface protection ?

Answer 3

-material
-function
-location

Question 4

what are the three groups of protective treatment?

Answer 4

-pre-treatment
-paint coatings
-special coatings

Question 5

when is paint applied to a metal surface ?

Answer 5

once the surface has received any form of anti-corrosive treatment or surface preparation designed to assist adhesion of the paint

Question 6

what are the steps before pre treatment and what are some examples of pre treatment ?

Answer 6

degreasing followed by a pre treatment such as anodising or chromating

Question 7

what is anodising ?

Answer 7

a pre treatment method, where the workpiece acts as the anode in an electrolytic cell to form oxide coatings to improve the performance of the surface

Question 8

what is chromating ?

Answer 8

a pre-treatment process that produces a protective oxide film and has a golden yellow appearance

Question 9

how is a workpiece chromated?

Answer 9

the most common method is to immerse the part in potassium dichromate.

Question 10

how can a chromate film be repaired if bare metal is showing ?

Answer 10

by swabbing the area with a chromate solution

Question 11

what is the primary reason to apply paint to an aircraft ?

Answer 11

to protect the skin from corrosion, abrasion and fluids

Question 12

what is important to remember about painting an aircraft ?

Answer 12

a singular paint will not suffice as different areas of an aircraft are subjected to different conditions

Question 13

what decides the effectiveness of a paint coating ?

Answer 13

preparation of a surface, paint shop needs to be well maintained, application of the paint

Question 14

what are the two types of paint coats ?

Answer 14

-primer:
increases corrosion resistance properties and gives good adhesion to the subsequent paint coatings
-topcoat:
protects the layers of the primer and gives the aircraft the necessary appearance

Question 15

why are special coatings used ?

Answer 15

to provide specialist corrosion protection for areas with tough conditions

Question 16

what are the two types of special coatings ?

Answer 16

-type 1
-type 2

Question 17

what type of special coating repels water and moisture ?

Answer 17

type 1 made of silicone free materials organically bound with a mineral oil base

Question 18

what type of special coating provides heavy duty corrosion prevention?

Answer 18

type 2 made from grease like coatings that contain corrosion inhibitors

Question 19

both type 1 and type 2 special coatings can be available in multiple grades, what are these grades ?

Answer 19

soft film-forming and hard film-forming