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2000 |
Example of one of the ca 100 experiments for studying "on-load" or Heat Flux Corrosion. Trend of internal wall temperature, pH-value in water separator and hydrogen production during the last 3 days of experiment 73. (foto KEMA, ref 11). |
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2002 |
Split test tube 73/180. Thermohydraulic conditions: Steam fraction: 0.09; Mass flow: 1100 kg/m2.s; Heat flux: 360 kW /m2. Dosings into the boiler water: suspension 65 mg/kg; sea water 23
mg/kg. The white lines indicate the locations where samples were removed for microscopic examination. The black lines indicate the irradiated part. (foto KEMA, ref 11). |
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2003 |
Sections through a corroded tube with 4 stages of "on-load corrosion". · On top of the thin magnetite layer a porous oxide layer (stage 1) is formed in which salt has deposited (stage 2). · Attack of the thin magnetite layer and formation of the top layer (stage 3). · Thick crust of layered oxide under the top layer (stage 4) (foto KEMA, ref 11). |
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2010 |
Test tube exposed under acid boiler water conditions. Seawater condensor leakage was imitated. Corrosion started particularly on the tube half with the highest heat flux and spread out over a large part of the tube. Cross section shows that the deposit layer with the salt deposit is pushed away by the corrosion product magnetite. (foto KEMA, ref 61). |
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2011 |
Left: Regular laminated oxide in a heavy corroded boiler tube because of a condensor leakage and acid boiler water. Right: Severely blistered corrosion scale. These both types of oxide layer are often found in heavy corroded boiler tubes because of acid forming condensor inleakage. (foto KEMA, ref 8, 23, 61). |
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2012 |
Corrosion crust with porous and blistered oxide. This type of oxide layer is also often found in heavy corroded boiler tubes because of acid forming condensor inleakage. Foto right shows that a compact oxide layer is present at the metal and at a small distance pores are formed. (foto KEMA, ref 61). |
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2013 |
A second example of forming of pores behind the compact oxide layer. (foto KEMA, ref 8 and 61). |
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2014 |
The pores behind the compact oxide on the metal surface develope often in blisters. A second example of blisters developing from pores. (foto KEMA, ref 8 and 61). |
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2015 |
Near the metal oxide interface the porous and blistered areas have a darker color. Analysis showed that much Chlorid is present in these dark grey coloured areas. (foto KEMA, ref 61). |
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2016 |
A trypical corrosion scale in acid boiler water. Aside the porosity and the blisters methane enbrittlement can be noticed in the steel. Right: detail of the brittlement. In case of heavy heat flux corrosion much hydrogen (from the corrosion process) can diffuse into the steel. The perlite phase can be transformed by the hydrogen in carbon and methane. This results in internal cracks along the grain boundaries along the perlite phase. (foto KEMA, ref 23, 61). |
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2016 |
Characteristic oxide scale on corroded boiler tubes. The 4 stages of the corrosion process can be recognized in the oxide crust. A: Porous layer of oxide deposits,
B: Salt layer, C: Top-layer, D: Laminated oxide, E: Steel. (foto KEMA, ref 13). |
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2020 |
Acid chloride corrosion scale under heat flux conditions. Maybe a stagnant steam bubble caused that underneath corrosion did not occur. (foto KEMA, ref 61). |
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2022 |
Section through samples at locations 105/ 12. On the irradiated side (d) the oxide layer is very porous and there are coarse magnetite crystals. On the not directly heated side the oxide layer is finely laminated. (foto KEMA, ref 11). |
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2023 |
Section of tube 73/ 180 at locations 117/ 12 (d). At the middle of the side with the greatest heat-input very porous oxide has formed. At the location with less heat-input (end of the oven, d) the oxide is finely laminated. (foto KEMA, ref 11). |
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2024 |
Sections through samples from tube 61/ 175. Between the oxide and the steel corrosive salt has been deposited (a and b). (foto KEMA, ref 11). |
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2025 |
Scanning electron microscope pictures of sample 61/ 175/ 103. It is found that the composition of the grey salt and of the clay-like structure is alike. Furthermore, the elements S and Cl are present. (foto KEMA, ref 11). |
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