| 1. |
- Sadeghimeresht, Esmaeil, 1985-, et al.
(författare)
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Chlorine-induced high temperature corrosion of HVAF-sprayed Ni-based alumina and chromia forming coatings
- 2018
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Ingår i: Corrosion Science. - : Elsevier BV. - 0010-938X .- 1879-0496. ; 132:March, s. 170-184
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Tidskriftsartikel (refereegranskat)abstract
- Chlorine-induced corrosion of HVAF-sprayed Ni21Cr and Ni5Al coatings was investigated in 5 vol.% O2 + 500vppm HCl + N2 with and without KCl at 600 °C up to 168 h. Both coatings were protective in the absence of KCl. With KCl, Ni21Cr degraded through a two-stage mechanism: 1) formation of K2CrO4 followed by diffusion of Cl− through the oxide grain boundaries to yield chlorine and a non-protective oxide, and 2) inward diffusion of chlorine though defects in the non-protective oxide, leading to breakaway oxidation. Cl−/Cl2 could not diffuse through the protective alumina scale formed on Ni5Al, hence the corrosion resistance increased.
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| 2. |
- Sadeghimeresht, Esmaeil, 1985-, et al.
(författare)
-
Influence of KCl and HCl on high temperature corrosion of HVAF-sprayed NiCrAlY and NiCrMo coatings
- 2018
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Ingår i: Materials & design. - : Elsevier BV. - 0264-1275 .- 1873-4197. ; 148, s. 17-29
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Tidskriftsartikel (refereegranskat)abstract
- The oxidation performance of NiCrAlY and NiCrMo coatings thermally sprayed by high velocity air-fuel (HVAF) technique has been investigated in a chloridizing-oxidizing environment, with and without a KCl deposit, at 600 °C for up to 168 h. Both coatings protected the substrate in the absence of KCl due to formation of a dense Cr-rich oxide scale. In the presence of KCl, Cl−/Cl2 diffused through a non-protective and porous NiCr2O4 scale formed on NiCrAlY, leading to formation of volatile CrCl3. On the other hand, Mo in NiCrMo stimulated the formation of a more protective Cr-rich oxide scale which increased the corrosion resistance by reducing Cl−/Cl2 diffusion.
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