The negative-difference effect during the localized corrosion of magnesium and of the AZ91HP alloy
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 s...
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| Format: | Article |
| Language: | English |
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Sociedade Brasileira de Química
2003-01-01
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| Series: | Journal of the Brazilian Chemical Society |
| Subjects: | |
| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532003000400015 |
| _version_ | 1818151935034785792 |
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| author | Weber Cristina R. Knörnschild Gerhard Dick Luís F. P. |
| author_facet | Weber Cristina R. Knörnschild Gerhard Dick Luís F. P. |
| author_sort | Weber Cristina R. |
| collection | DOAJ |
| 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. |
| first_indexed | 2024-12-11T13:46:43Z |
| format | Article |
| id | doaj.art-8d07da593e7d4ec89344b2b0d5a00245 |
| institution | Directory Open Access Journal |
| issn | 0103-5053 |
| language | English |
| last_indexed | 2024-12-11T13:46:43Z |
| publishDate | 2003-01-01 |
| publisher | Sociedade Brasileira de Química |
| record_format | Article |
| series | Journal of the Brazilian Chemical Society |
| spelling | doaj.art-8d07da593e7d4ec89344b2b0d5a002452022-12-22T01:04:27ZengSociedade Brasileira de QuímicaJournal of the Brazilian Chemical Society0103-50532003-01-01144584593The negative-difference effect during the localized corrosion of magnesium and of the AZ91HP alloyWeber Cristina R.Knörnschild GerhardDick Luís F. P.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.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532003000400015magnesiumlocalized corrosionAZ91HP alloynegative-difference effect |
| spellingShingle | Weber Cristina R. Knörnschild Gerhard Dick Luís F. P. The negative-difference effect during the localized corrosion of magnesium and of the AZ91HP alloy Journal of the Brazilian Chemical Society magnesium localized corrosion AZ91HP alloy negative-difference effect |
| title | 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_short | The negative-difference effect during the localized corrosion of magnesium and of the AZ91HP alloy |
| title_sort | negative difference effect during the localized corrosion of magnesium and of the az91hp alloy |
| topic | magnesium localized corrosion AZ91HP alloy negative-difference effect |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532003000400015 |
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