Transcript Presentation Title - Institute of Materials Finishing

Corrosion results Airbus structural systems.
System 1: Conventional solvent based chromated primer + Low solids PUR topcoat
System 2: Water based chromated primer + Water based epoxy topcoat.
System 3: Water based chromate-free primer + Water based epoxy topcoat.
Filiform corrosion 2024T3 Bare
6
max. fili (mm)
5
4
Cr - SB
3
Cr - WB
CF - WB
2
1
CAA and TSA: 2000 h. Filiform
0
CAA
TSA
CSP
Scotch Brite
CSP and SB: 1000 h. Filiform
Filiform Corrosion 2024T3 Clad
6
Max. fili (mm)
5
4
Cr - SB
3
Cr - WB
CF - WB
2
1
0
CAA
TSA
CSP
Scotch Brite
Akzo Nobel Aerospace Coatings
1
Filiform corrosion results Boeing exterior system on
different alloys and Boegel pretreatment.
CF-System: High solids chromate-free epoxy-amine primer + HS PUR Topcoat.
Cr.-System: High solids chromated epoxy-amine primer + HS PUR Topcoat.
Filiform corrosion 1000 h. 2024T3 and 7075T6 to BMS 10-72
Boeing requirements: 720 hours
6
2024T3 - max. 0.125 inch / 3.2 mm.
max. fili (mm)
7075T6 - max. 0.35 inch / 8.9 mm
5
4
360 h
3
720 h
1000 h
2
1
0
CF-2024
CF-7075
Cr-2024
Cr-7075
Akzo Nobel Aerospace Coatings
2
Chromate-free BMS 10-72 system on different alloys.
2024T3 + Boegel
7075T6 + Boegel
Akzo Nobel Aerospace Coatings
3
Chromate BMS 10-72 system on different alloys.
2024T3 + Boegel
7075T6 + Boegel
Akzo Nobel Aerospace Coatings
4
NSS exposure to BMS 10-72 of different systems.
creep from scribe (mm)
Results after 1000 h NSS (ASTM B117) exposure on
2024 T3 Clad and 7075 T6 Clad
5
50
45
40
35
30
25
20
15
10
5
0
4
3
2
1
0
sample 1 sample 2 sample 3 sample 4
sample 1 sample 2 sample 3 sample 4
2024 T3 2024 T3 2024 T3 2024 T3
Clad
Clad
Clad
Clad
7075 T6 7075 T6 7075 T6 7075 T6
Clad
Clad
Clad
Clad
creep
# corrosion sites
Sample 1- 3: Chromate-free primer - topcoat system on Boegel
Sample 4:
Chromate primer - topcoat system on Boegel
Akzo Nobel Aerospace Coatings
5
NSS to BMS 10-72 (1500 h.) on 2024T3 clad:
CF and Chromate primer + HS PUR topcoat.
HS chromate-free primer
Boegel
HS chromate primer
Boegel
Akzo Nobel Aerospace Coatings
6
NSS to BMS 10-72 (1500 h.) on 7075T6 clad:
CF and Chromate primer + HS PUR topcoat.
HS chromate-free primer
Boegel
HS chromate primer
Boegel
Akzo Nobel Aerospace Coatings
7
Effect of primer on scribe protection in NSS.
Chromate-free primer
Chromate primer
1000 hours exposure of BMS 10-72 system on 2024T3 clad.
Akzo Nobel Aerospace Coatings
8
Conclusions.
 Airbus structural primer / system corrosion requirements:
- On TSA pretreatment, CF Primer technology is still slightly outside the
requirements.
 Boeing exterior system corrosion requirements:
- On Boegel pretreatment the CF Primer – topcoat technology is able to
meet the requirements.
 AMS 3095 Maintenance system corrosion requirements:
- The current CF primer technology is not yet able to meet the high
requirements on Scotch Brite solvent cleaned bare 2024T3.
 The aluminium pretreatment is a very important factor in the coating
adhesion and corrosion protection of the primer / system.
Akzo Nobel Aerospace Coatings
9