The negative-difference effect during the localized corrosion of magnesium and of the AZ91HP alloy
Autor(a) principal: | |
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Data de Publicação: | 2003 |
Outros Autores: | , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Journal of the Brazilian Chemical Society (Online) |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532003000400015 |
Resumo: | Galvanostatic tests with pure magnesium and with the AZ91HP alloy were performed in NaCl solutions, and the volume of hydrogen evolved during the tests was measured. In order to examine the negative-difference effect, a concept was developed to separate the hydrogen evolution (H.E.) on the passive surface and the H.E. inside the pits. An analysis of the volumetric data showed that the current density of H.E. inside the pits is much higher for Mg than for the AZ91HP alloy. With the assumption, that the ratio between the hydrogen reduction rate and the rate of the anodic metal dissolution, expressed by the factor k, does not change with the polarization, a k value of ca. 0.5 for pure Mg was found, while for the AZ91HP alloy this value was only ca. 0.3. |
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Journal of the Brazilian Chemical Society (Online) |
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The negative-difference effect during the localized corrosion of magnesium and of the AZ91HP alloymagnesiumlocalized corrosionAZ91HP alloynegative-difference effectGalvanostatic tests with pure magnesium and with the AZ91HP alloy were performed in NaCl solutions, and the volume of hydrogen evolved during the tests was measured. In order to examine the negative-difference effect, a concept was developed to separate the hydrogen evolution (H.E.) on the passive surface and the H.E. inside the pits. An analysis of the volumetric data showed that the current density of H.E. inside the pits is much higher for Mg than for the AZ91HP alloy. With the assumption, that the ratio between the hydrogen reduction rate and the rate of the anodic metal dissolution, expressed by the factor k, does not change with the polarization, a k value of ca. 0.5 for pure Mg was found, while for the AZ91HP alloy this value was only ca. 0.3.Sociedade Brasileira de Química2003-08-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532003000400015Journal of the Brazilian Chemical Society v.14 n.4 2003reponame:Journal of the Brazilian Chemical Society (Online)instname:Sociedade Brasileira de Química (SBQ)instacron:SBQ10.1590/S0103-50532003000400015info:eu-repo/semantics/openAccessWeber,Cristina R.Knörnschild,GerhardDick,Luís F. P.eng2003-09-16T00:00:00Zoai:scielo:S0103-50532003000400015Revistahttp://jbcs.sbq.org.brONGhttps://old.scielo.br/oai/scielo-oai.php||office@jbcs.sbq.org.br1678-47900103-5053opendoar:2003-09-16T00:00Journal of the Brazilian Chemical Society (Online) - Sociedade Brasileira de Química (SBQ)false |
dc.title.none.fl_str_mv |
The negative-difference effect during the localized corrosion of magnesium and of the AZ91HP alloy |
title |
The negative-difference effect during the localized corrosion of magnesium and of the AZ91HP alloy |
spellingShingle |
The negative-difference effect during the localized corrosion of magnesium and of the AZ91HP alloy Weber,Cristina R. magnesium localized corrosion AZ91HP alloy negative-difference effect |
title_short |
The negative-difference effect during the localized corrosion of magnesium and of the AZ91HP alloy |
title_full |
The negative-difference effect during the localized corrosion of magnesium and of the AZ91HP alloy |
title_fullStr |
The negative-difference effect during the localized corrosion of magnesium and of the AZ91HP alloy |
title_full_unstemmed |
The negative-difference effect during the localized corrosion of magnesium and of the AZ91HP alloy |
title_sort |
The negative-difference effect during the localized corrosion of magnesium and of the AZ91HP alloy |
author |
Weber,Cristina R. |
author_facet |
Weber,Cristina R. Knörnschild,Gerhard Dick,Luís F. P. |
author_role |
author |
author2 |
Knörnschild,Gerhard Dick,Luís F. P. |
author2_role |
author author |
dc.contributor.author.fl_str_mv |
Weber,Cristina R. Knörnschild,Gerhard Dick,Luís F. P. |
dc.subject.por.fl_str_mv |
magnesium localized corrosion AZ91HP alloy negative-difference effect |
topic |
magnesium localized corrosion AZ91HP alloy negative-difference effect |
description |
Galvanostatic tests with pure magnesium and with the AZ91HP alloy were performed in NaCl solutions, and the volume of hydrogen evolved during the tests was measured. In order to examine the negative-difference effect, a concept was developed to separate the hydrogen evolution (H.E.) on the passive surface and the H.E. inside the pits. An analysis of the volumetric data showed that the current density of H.E. inside the pits is much higher for Mg than for the AZ91HP alloy. With the assumption, that the ratio between the hydrogen reduction rate and the rate of the anodic metal dissolution, expressed by the factor k, does not change with the polarization, a k value of ca. 0.5 for pure Mg was found, while for the AZ91HP alloy this value was only ca. 0.3. |
publishDate |
2003 |
dc.date.none.fl_str_mv |
2003-08-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532003000400015 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532003000400015 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/S0103-50532003000400015 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
Sociedade Brasileira de Química |
publisher.none.fl_str_mv |
Sociedade Brasileira de Química |
dc.source.none.fl_str_mv |
Journal of the Brazilian Chemical Society v.14 n.4 2003 reponame:Journal of the Brazilian Chemical Society (Online) instname:Sociedade Brasileira de Química (SBQ) instacron:SBQ |
instname_str |
Sociedade Brasileira de Química (SBQ) |
instacron_str |
SBQ |
institution |
SBQ |
reponame_str |
Journal of the Brazilian Chemical Society (Online) |
collection |
Journal of the Brazilian Chemical Society (Online) |
repository.name.fl_str_mv |
Journal of the Brazilian Chemical Society (Online) - Sociedade Brasileira de Química (SBQ) |
repository.mail.fl_str_mv |
||office@jbcs.sbq.org.br |
_version_ |
1750318165338882048 |