Corrosion rate of construction materials in hot phosphoric acid with the contribution of anodic polarization

Publication: Research - peer-reviewJournal article – Annual report year: 2011

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Corrosion rate of construction materials in hot phosphoric acid with the contribution of anodic polarization. / Kouril, M.; Christensen, Erik; Eriksen, S.; Gillesberg, B.

In: Materials and Corrosion, Vol. 62, No. 9999, 2011.

Publication: Research - peer-reviewJournal article – Annual report year: 2011

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Kouril, M.; Christensen, Erik; Eriksen, S.; Gillesberg, B. / Corrosion rate of construction materials in hot phosphoric acid with the contribution of anodic polarization.

In: Materials and Corrosion, Vol. 62, No. 9999, 2011.

Publication: Research - peer-reviewJournal article – Annual report year: 2011

Bibtex

@article{c67ad50e33de458aa99e5de330103ef4,
title = "Corrosion rate of construction materials in hot phosphoric acid with the contribution of anodic polarization",
publisher = "Wiley - V C H Verlag GmbH & Co. KGaA",
author = "M. Kouril and Erik Christensen and S. Eriksen and B. Gillesberg",
year = "2011",
doi = "10.1002/maco.201006021",
volume = "62",
number = "9999",
journal = "Materials and Corrosion",
issn = "0947-5117",

}

RIS

TY - JOUR

T1 - Corrosion rate of construction materials in hot phosphoric acid with the contribution of anodic polarization

A1 - Kouril,M.

A1 - Christensen,Erik

A1 - Eriksen,S.

A1 - Gillesberg,B.

AU - Kouril,M.

AU - Christensen,Erik

AU - Eriksen,S.

AU - Gillesberg,B.

PB - Wiley - V C H Verlag GmbH & Co. KGaA

PY - 2011

Y1 - 2011

N2 - The paper is focused on selection of a proper material for construction elements of water electrolysers, which make use of a 85% phosphoric acid as an electrolyte at temperature of 150 8C and which might be loaded with anodic polarization up to 2.5 V versus a saturated Ag/AgCl electrode (SSCE). Several grades of stainless steels were tested as well as tantalum, niobium, titanium, nickel alloys and silicon carbide. The corrosion rate was evaluated by means of mass loss at free corrosion potential as well as under various levels of polarization. The only corrosion resistant material in 85% phosphoric acid at 150 8C and at polarization of 2.5 V/SSCE is tantalum. In that case, even a gentle cathodic polarization is harmful in such an acidic environment. Hydrogen reduction leads to tantalum hydride formation, to loss of mechanical properties and to complete disintegration of the metal. Contrary to tantalum, titanium is free of any corrosion resistance in hot phosphoric acid. Its corrosion rate ranges from tens of millimetres to metres per year depending on temperature of the acid. Alloy bonded tantalum coating was recognized as an effective corrosion protection for both titanium and stainless steel. Its serviceability might be limited by slow dissolution of tantalum that is in order of units of mm/year.

AB - The paper is focused on selection of a proper material for construction elements of water electrolysers, which make use of a 85% phosphoric acid as an electrolyte at temperature of 150 8C and which might be loaded with anodic polarization up to 2.5 V versus a saturated Ag/AgCl electrode (SSCE). Several grades of stainless steels were tested as well as tantalum, niobium, titanium, nickel alloys and silicon carbide. The corrosion rate was evaluated by means of mass loss at free corrosion potential as well as under various levels of polarization. The only corrosion resistant material in 85% phosphoric acid at 150 8C and at polarization of 2.5 V/SSCE is tantalum. In that case, even a gentle cathodic polarization is harmful in such an acidic environment. Hydrogen reduction leads to tantalum hydride formation, to loss of mechanical properties and to complete disintegration of the metal. Contrary to tantalum, titanium is free of any corrosion resistance in hot phosphoric acid. Its corrosion rate ranges from tens of millimetres to metres per year depending on temperature of the acid. Alloy bonded tantalum coating was recognized as an effective corrosion protection for both titanium and stainless steel. Its serviceability might be limited by slow dissolution of tantalum that is in order of units of mm/year.

U2 - 10.1002/maco.201006021

DO - 10.1002/maco.201006021

JO - Materials and Corrosion

JF - Materials and Corrosion

SN - 0947-5117

IS - 9999

VL - 62

ER -