Marine Corrosion Protection
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Transcript of Marine Corrosion Protection
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Corrosion Protection SEO ViandenQuality of Coating Products
Studies by the SEO Construction Departmentof Selected Products
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 2
Introduction
• Purpose of the studies:
Determining the quality of the coating systems for difficult corrosion protection in hydraulic steel structures.
Comparison of various corrosion protection products.
Statements concerning the durability of the protective effect of the various corrosion protection products.
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 3
Main Topics
• Function of the coating materials
• Properties of the coating materials
• Test methods
• Water diffusion test (description/results)
• Findings
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 4
Function of the coating materials
• Coating materials are supposed to maintain a barrier function between steel (substrate) and water, which lasts as long as possible, in order to prevent corrosion damage.
• For this purpose, they must be as watertight as possible .
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 5
Properties of the coating materials
• The polymer structure of the coating materials results in a greater or lesser porosity of the coating film.
• This permits water to penetrate as a function of the type and quality of the binder, the pigments/fillers, and solvent content, etc.
• Coatings can be regarded as a permeable membrane (more or less solid, cross-linked polymer film).
• Diffusion depends on the structure and thickness of the covering layer .
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 6
Diffusion and its consequencesFunctional mechanism
• Corrosion residues and salts on the steel surface, which strive to become diluted, attract water through the coating (e.g. iron sulfate).
• Salt solutions form on the steel surface and this results in a concentration gradient between the outside and the inside of the coating.
• An osmotic pressure develops, which allows more and more water to flow through the coating in the direction of the substrate (steel).
• Bubbles filled with water form on the coating, leading to the detachment of the coating and finally to its bursting.
• This leads to local corrosion damage at first, later to large-area corrosion damage (pitting, rust, etc.)
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 7
Material transport through coatingsConsequences for the coating
Water absorption, caused by osmosis, depends on the binder and the pigmentation.
→ it brings about swelling of the coating a decrease in cohesion and,
with that, a decrease in tensile strength perpendicular to the surface (cohesion rupture)
→ it influences the chemical bonding of the coating to the substrate Decrease in adhesion Bubbles or loosened areas occur.
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 8
Practical example:
Ball valve pressure plate TU2, coated in 1999, partially stressed (with Sika Poxitar SW 200-250 µm), findings after eight years
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 9
Other factors can influence the diffusion process:
• Salt residues, dust, dirt on the substrate
• Solvents in the coating
• Water quality
• Binder residues, which have not been cured
• Primers, base coats
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 10
The following counteract the diffusion process:
• Diffusion resistance of the product
• Layer thickness of the product
• Adhesion strength of the coating
• Cleanliness of the substrate surface
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 11
Test methods used for quality studies of substrate and coating material (at SEO)
Substrate quality: -Visual comparison with standardized comparison samples,
-Salt concentration studies ,
-Examination for dust residues ,
-Measurements of the roughness of the steel surface
• Tensile Adhesive Adhesion testing equipment (tensile force perpendicular strength : to the die that is glued on)
• Diffusion resistance: Δ-T Test
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 12
Diffusion resistance / Δ-T Test:Test arrangement (thermodiffusion)
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 13
Diffusion resistance / -T TestOf central importance for corrosion protection
Parameters determining the diffusion rate of water through the coating to be tested:
• Temperature (Gradient,Difference)
• Layer thickness
• Quality of the coating
• Application of the coating
Assessment criterion :
Diffusion period in days until bubbles appear on the coating surface
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 14
Criteria in similar tests by the main RWE Laboratory
Studies for the selection of products for coating the pressure lines 1 and 2 of the PS power plant Vianden 1997/98)
• A coating should withstand the tube test for approximately 20 days (at 40/10°C) without forming bubbles, in order to be able to achieve a resistance of at least 20 years (experience of RWE laboratory).
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 15
Coating after diffusion of water(in the thermodiffusion test)
Example:Tenaxon 555CS (version 2007, epoxy, solvent-based,
average layer thickness 500 µm)Outside bath temperature 40°C/inside temperature
in experimental tube 10°CTime period until the first bubbles appear: 2 days
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 16
Coating after diffusion of water in the thermodiffusion test (-T Test)
Example:
Caparol Disbon 705
Polibrid coating
600 to 1500 µm
Time period until bubbles form
approximately 10 days in the
region of 700 µm
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 17
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 18
Comparison of test tube test / WDD test according to DIN EN ISO 6270
(Water vapor (40°C) applied to plate, back side: air (20-25°C), layer thickness 500 µm, bubbles form after approximately 1 year in the case of ICOSIT)
SIKA ICOSIT 500 SW ACOTEC HUMIDUR ML
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 19
Diffusion period in days until the appearance of bubbles on the coated surface in relation to the layer thickness in µm
(Selection from more than 40 different tests and products until now)
Steam diffusion test 40/10
0 10 20 30 40 50 60 70 80 90 100
Humidur ML 1999
Humidur ML 2004
Humidur ML 2005
Humidur ML 2005 better
Humidur ML TU 5 (2005)
Humidur ML 2006
Humidur ML + (Carboline Primer) 2007
Humidur ME (grau) 2007
Aquapure Fast
Aquapure Slow
Aquapure Schnell-Slow
Icosit SW 500
Inertol Poxitar SW
Icosit Poxicolor SW
Icosit 299 HS
Agopur Elastik
Agrovan 209
Ceram Kote SPG
Epiter 130 TF
Permacor 136 TW
Softturb
International Paint Interzone 954
JAK Versapox
LECO UWB-E 48
Tenaxon 555 CS (coated on May 4, 2007)
Co
ati
ng
pro
du
cts
days
0 500 1000 1500 2000 2500
Value in micrometers
Days
Average in micrometers
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 20
Conclusions from the Table: Durability of the corrosion protection
Based on the results found in the diffusion test and the previous results from the RWE laboratory tests, there are only
• a few coating materials that pass the test over a period of more than 17-20 days, at an average layer thickness of 500 µm, without forming bubbles:
• HumidurML from 1999 at 400 µm 17 days (with 2 mm tube)• (More recent batches, however, show lower values in spite of repeated
complaints raw materials for the curing agent have been changed)
• Aquapure HR: at 480 µm, more than 90 days without forming bubbles
• Interzone 954: at 350 µm 45 days (solvent-based)
• CeramKote 54: at 500 µm more than 40 days without forming bubbles
• Epiter 130 TF: at 400 µm 21 days (solvent-based)
• These products will offer long-term corrosion protection if applied correctly.
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 21
Findings
• The coating will last longer if its diffusion resistance is higher.
• Water is kept away from the substrate as long as possible.
• Any contaminants that might be present will react more slowly.
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 22
Selection criteria for application in the various water power plant sectors:
• Long durability of the corrosion protection
• Application method
• Ease of repair
• Environment and health
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 23
Application methods
For application in accordance with good practice, the following criteria should be observed:
- Application temperatures (substrate, coating, atmosphere)
- Equipment (spraying, brush-coating)
- Processing time (pot life)
- Ability to apply multiple coatings (multiple layers, repairs)
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 24
Environment and Health
The products selected must not contain any materials that are harmful to the environment and to health:
(VOC guideline and REACH regulations)
• no solvents
• no polycyclic aromatic hydrocarbons
• no carcinogenic materials
• n components that contaminate water
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 25
Advantages and disadvantages of the aforementioned products in comparison with one another:
Humidur ML 1999
5/1weight
Aquapure HR
1/1
Interzone 954
4/1vol
EPITER TF 130
4/1weight
Ceram-Kote54
6.7/1weight
Diffusion resistance
in days for 500-600 µm
20 ~ >90 ++++
(for 300µm 35days.)
45 ++ 21 ~0 >40 ++
Solvent content none none VOC 130g/l VOC 28g/l VOC168g/l
R groups R21/22/23/24/25/34/36/
38/39/43/45/48/51/52/53
/68/
R45 carcinogenic
R34/43/20/22/36/38/
43//51/53
R10/11/20/21/22/34/
36/37/38/43/51/52/5
3/66
R11/20/36/37/38/43/2
1/22/34/37/51/53/66/6
7/
Allowed for drinking water no yes no no no
Max. layer thickness
Min. layer thickness /
370µm
/
350µm
125µm
450µm
/
450µm
125µm
450µm
Adhesion strength N/mm2 >20 >20 >20 >15 /
Processing
Pot life at 18°C in min
Manual processing
40
good
30
very good
90-120
poor
45
good very poor
10.04.23Untersuchungen an Korrosionsschutzprodukten für den Stahlwasserbau / C.Tonino 26
Next Steps
• Detailed study of the Aquapure HR und Interzone 954 by the RWE laboratory; comparison with HUMIDUR ML (1999/2007)
Further studies of other productse.g. products that are being used by EDF in France