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Effect of impurities in a nickel sulfate electrolyte on internal stress development morphology and adhesion to titanium of electrodeposited nickel
Dissertation (MSc)--University of Pretoria, 2017.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2019
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| _version_ | 1867613554324013056 |
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| access_status_str | Open Access |
| author2 | Sandenbergh, R.F. |
| author_browse | Sandenbergh, R.F. |
| author_facet | Sandenbergh, R.F. |
| collection | Thesis |
| dc_rights_str_mv | © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc)--University of Pretoria, 2017. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/71160 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:59.731Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2019 |
| publishDateRange | 2019 |
| publishDateSort | 2019 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/71160 Effect of impurities in a nickel sulfate electrolyte on internal stress development morphology and adhesion to titanium of electrodeposited nickel Sandenbergh, R.F. u12282996@tuks.co.za Nsiengani, Emmanuel Nsanda UCTD Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 Dissertation (MSc)--University of Pretoria, 2017. Successful electrowinning and electrorefining processes for the production of high purity and compact electroplated metal require the optimization of the electrolyte composition and operating parameters. In nickel electrowinning and electrorefining plants the optimization of the electrolyte composition for good deposit morphology, optimal adhesion to the substrate, and minimum energy requirements remains a challenge. The influence of some impurities usually present in nickel sulfate electrolytes on the stress level, morphology and adhesion of nickel deposits were investigated using both quantitative and qualitative assessments, such as internal stress, adhesion, grain size and chemical composition measurements, complemented by visual observation of the morphology and condition of the plated nickel. The results indicate that both the internal stress and yield stress increased, but at different rates, with impurities such as copper, cobalt, chromium and aluminium in the electrolyte. The impurity level at which the internal stress exceeded the yield stress typically resulted in cracking and/or disbonding of the plated metal and could be used to define the allowable impurity levels. The impurity metal contents of the plated nickel increased proportionally to the concentrations of copper, cobalt and chromium in the electrolyte, but not so in the case of aluminium where a maximum was found at an intermediate concentration in the range of concentrations studied. The measured internal stress in the deposits followed the trend of impurity contents in the nickel for aluminium, chromium and copper, while a slight decrease in internal stress was observed at low cobalt concentrations in the electrolyte. It was also found that nickel adhesion to the titanium substrate is relatively weaker in the presence of impurities, with aluminum being the worse impurity, followed by copper, cobalt and chromium impurities, respectively. mi2026 Materials Science and Metallurgical Engineering MSc Unrestricted SDG-09: Industry, innovation and infrastructure SDG-12: Responsible consumption and production 2019-08-21T09:33:15Z 2019-08-21T09:33:15Z 2018 2017 Dissertation Nsiengani, EN 2017, Effect of impurities in a nickel sulfate electrolyte on internal stress development morphology and adhesion to titanium of electrodeposited nickel, MSc Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/71160> A2018 http://hdl.handle.net/2263/71160 en © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 Effect of impurities in a nickel sulfate electrolyte on internal stress development morphology and adhesion to titanium of electrodeposited nickel |
| title | Effect of impurities in a nickel sulfate electrolyte on internal stress development morphology and adhesion to titanium of electrodeposited nickel |
| title_full | Effect of impurities in a nickel sulfate electrolyte on internal stress development morphology and adhesion to titanium of electrodeposited nickel |
| title_fullStr | Effect of impurities in a nickel sulfate electrolyte on internal stress development morphology and adhesion to titanium of electrodeposited nickel |
| title_full_unstemmed | Effect of impurities in a nickel sulfate electrolyte on internal stress development morphology and adhesion to titanium of electrodeposited nickel |
| title_short | Effect of impurities in a nickel sulfate electrolyte on internal stress development morphology and adhesion to titanium of electrodeposited nickel |
| title_sort | effect of impurities in a nickel sulfate electrolyte on internal stress development morphology and adhesion to titanium of electrodeposited nickel |
| topic | UCTD Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 |
| url | http://hdl.handle.net/2263/71160 |