1 2 1 2 CORROSION PERFORMANCE OF THERMAL SPRAYED ALUMINUM ... · PDF file• Cycle Norsok...
1
Samples preparation: uncoated (A), coated (B) and coated with damages (C) Contact Information: Jean-Baptiste Jorcin T +34 667 101 435 [email protected] TECNALIA Parque Científico y Tecnológico de Gipuzkoa Mikeletegi Pasalekua, 2 E-20009 Donostia-San Sebastián (Gipuzkoa) T 902 760 000* T +34 946 430 850 (International calls) www.tecnalia.com Aintzane Exposito 1 , Jean-Baptiste Jorcin 2 , Alberto Arredondo 1 , Elena Rodríguez 1 1 Vicinay Marine Innovación, Plaza Ibaiondo ,1, 48940 Leioa, Spain 2 Tecnalia Research & Innovation, Parque Tecnológico de San Sebastián, Mikeletegi Pasealekua, 2, E-20009 Donostia-San Sebastián, Spain Introduction CORROSION PERFORMANCE OF THERMAL SPRAYED ALUMINUM COATING IN OFFSHORE MOORING CHAINS . Controlled environment With 39% of the mooring chain failures related to different corrosion mechanisms 1 , finding a solution to delay or avoid this degradation phenomenon has become one of the offshore industry main concerns. The solution proposed by Vicinay since 2001 to enhance the corrosion resistance of the mooring lines is applying a Thermal Sprayed Aluminum (TSA) coating over the links. The purpose of the work presented here was to assess the effectiveness of the protection given by the TSA. 1 Fontaine, E., Kilner, A., Carra, C., Washington, D., Ma, K.T., Phadke, A., Laskoswki, D., Kusinski, G., “Industry Survey of Past Failures, Pre-emptive Replacements and Reported Degradations for Mooring Systems of Floating Production Units” OTC-25273-MS. Offshore Technology conference . Houston, USA, 2014. Laboratory study Scale-up study Conclusion • Cycle: 0.5h salt spray (ASTM B117) + 1h drying for 720h (1) • Immersion in 3,52% NaCl for 720h (2) • Cycle Norsok (ISO 20340): 3 days UV/Condensation + 3 days salt spray + 1 day -20ºC for 720h (3) Artificial ageing High degradation Very low degradation Very low degradation • Immersion in 3.52% NaCl for 835h Artificial ageing with cathodic overprotection (-1.2v vs Ag/AgCl) (1) (2) (3) (A) (B) (C) (A) (B) (C) Slight degradation of the TSA Delamination ≈ 1.5mm around the defect: Good resistance. Increase of the TSA consumption Sacrificial effect Samples preparation: • Uncoated • Half coated • Coated Constant load test (80% yield strength) in NaCl 3.52% for 720h: No sign of hydrogen embrittlement sensitivity Real environment • Not sensitive to hydrogen embrittlement. • Good behavior during the scale-up test, in both controlled and real environment. The use of TSA to protect the structural steel of mooring lines appears to be a very relevant solution. Artificial ageing + characterization Constant load tests Samples: 3 pairs of links: • TSA coated –TSA coated • TSA coated – Uncoated • Uncoated – Uncoated Immersed in a container with recirculated synthetic sea water containing 3.52%NaCl for 1 year. The environmental conditions : T ≈ 24ºC, pH ≈ 8, oxygen saturation ≈ 80% (concentration ≈ 7ppm). Aspect after 1 year of immersion Uncoated links: SEM analysis. Thick, adherent black corrosion product layer above the steel: complex system iron oxides with chemistry close to the magnetite Fe 3 O 4 with the addition of other metallic cations. TSA coated links: SEM analysis. The TSA layer can be clearly seen. After 1 year of immersion, it still have a thickness of 400μm. TSA coated links: SEM analysis of flakes During the test, some flakes detached from the coated links. EDS analysis showed the presence of aluminum indicating that part of the TSA was detaching from the link Link AE.5.2 AE.5.4 AE.5.16 Surface Uncoated (joined to a coated link) Uncoated Coated Corrosion rate (mm/year) 0.04 0.14 0 Comparison between links before and after exposition with 3D scanning methods and estimation of corrosion rate Aspect after 1 year of immersion Samples: 3 pairs of links: • TSA coated –TSA coated • TSA coated – Uncoated • Uncoated – Uncoated Immersed in the port of PASAIA (Spain) for 1 year. The place is characterized by: • Important biofouling • pH≈8, oxygen sat. average 70%, Temp. average 18ºC The TSA coating on mooring chain steel presented the following properties: • Good behavior during the artificial ageing, even in very harsh condition. • Sacrificial effect in favor of the steel in case of coating damages. • Good behavior under cathodic protection. • Without cathodic protection (CP) • With CP: -0.85 and -1.2 V vs Ag/AgCl
Transcript of 1 2 1 2 CORROSION PERFORMANCE OF THERMAL SPRAYED ALUMINUM ... · PDF file• Cycle Norsok...
Sam
ple
s p
rep
ara
tio
n:
un
co
ate
d (
A),
co
ate
d (
B)
an
d
co
ate
d w
ith
dam
ag
es (
C)
Contact Information:
Jean-Baptiste Jorcin
T +34 667 101 435
TECNALIA
Parque Científico y Tecnológico de Gipuzkoa
Mikeletegi Pasalekua, 2
E-20009 Donostia-San Sebastián (Gipuzkoa)
T 902 760 000*
T +34 946 430 850 (International calls)
www.tecnalia.com
Aintzane Exposito1 , Jean-Baptiste Jorcin2, Alberto Arredondo1, Elena Rodríguez1
1 Vicinay Marine Innovación, Plaza Ibaiondo ,1, 48940 Leioa, Spain
2 Tecnalia Research & Innovation, Parque Tecnológico de San Sebastián, Mikeletegi Pasealekua, 2, E-20009 Donostia-San Sebastián, Spain
Introduction
CORROSION PERFORMANCE OF THERMAL SPRAYED
ALUMINUM COATING IN OFFSHORE MOORING CHAINS
.
Controlled environment
With 39% of the mooring chain failures related to different corrosion
mechanisms1, finding a solution to delay or avoid this degradation
phenomenon has become one of the offshore industry main concerns. The
solution proposed by Vicinay since 2001 to enhance the corrosion resistance
of the mooring lines is applying a Thermal Sprayed Aluminum (TSA) coating
over the links.
The purpose of the work presented here was to assess the effectiveness of
the protection given by the TSA. 1 Fontaine, E., Kilner, A., Carra, C., Washington, D., Ma, K.T., Phadke, A., Laskoswki, D., Kusinski, G., “Industry Survey of Past Failures, Pre-emptive Replacements and Reported Degradations for Mooring Systems of Floating Production Units”
OTC-25273-MS. Offshore Technology conference . Houston, USA, 2014.
Laboratory study
Scale-up study
Conclusion
• Cycle: 0.5h salt spray (ASTM B117) + 1h drying
for 720h (1)
• Immersion in 3,52% NaCl for 720h (2)
• Cycle Norsok (ISO 20340):
3 days UV/Condensation + 3 days salt spray + 1
day -20ºC for 720h (3)
Artificial ageing
High
degradation
Very low
degradation
Very low
degradation
• Immersion in 3.52% NaCl for 835h
Artificial ageing with cathodic overprotection (-1.2v vs Ag/AgCl)
(1) (2) (3)
(A)
(B)
(C)
(A) (B) (C)
Slight
degradation
of the TSA
Delamination ≈ 1.5mm around the
defect: Good resistance. Increase
of the TSA consumption
Sacrificial effect
Samples preparation:
• Uncoated
• Half coated
• Coated
Constant load test (80% yield
strength) in NaCl 3.52% for 720h:
No sign of hydrogen embrittlement
sensitivity
Real environment
• Not sensitive to hydrogen embrittlement.
• Good behavior during the scale-up test, in both controlled and real environment.
The use of TSA to protect the structural steel of mooring lines appears to be a very
relevant solution.
Artificial ageing
+
characterization Constant load
tests
Samples: 3 pairs of links:
• TSA coated –TSA coated
• TSA coated – Uncoated
• Uncoated – Uncoated
Immersed in a container with recirculated
synthetic sea water containing 3.52%NaCl
for 1 year.
The environmental conditions : T ≈ 24ºC, pH ≈ 8, oxygen saturation ≈ 80%
(concentration ≈ 7ppm).
Aspect after 1
year of
immersion
Uncoated links: SEM analysis.
Thick, adherent black corrosion product
layer above the steel: complex system
iron oxides with chemistry close to the
magnetite Fe3O4 with the addition of
other metallic cations.
TSA coated links: SEM analysis.
The TSA layer can be clearly seen.
After 1 year of immersion, it still have a
thickness of 400µm.
TSA coated links: SEM analysis of flakes
During the test, some flakes detached from the coated
links. EDS analysis showed the presence of aluminum
indicating that part of the TSA was detaching from the link
Link AE.5.2 AE.5.4 AE.5.16
Surface Uncoated (joined to a coated link) Uncoated Coated
Corrosion rate (mm/year) 0.04 0.14 0
Comparison between links before and after
exposition with 3D scanning methods and
estimation of corrosion rate
Aspect after 1 year of immersion Samples: 3 pairs of links:
• TSA coated –TSA coated
• TSA coated – Uncoated
• Uncoated – Uncoated
Immersed in the port of
PASAIA (Spain) for 1 year.
The place is characterized by:
• Important biofouling • pH≈8, oxygen sat. average
70%, Temp. average 18ºC
The TSA coating on mooring chain steel presented the following
properties:
• Good behavior during the artificial ageing, even in very harsh condition.
• Sacrificial effect in favor of the steel in case of coating damages.
• Good behavior under cathodic protection.
• Without cathodic
protection (CP)
• With CP: -0.85 and -1.2 V
vs Ag/AgCl
