Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/129152
Title: ELECTRODEPOSITION OF NI-W AMORPHOUS AND NANOCRYSTALLINE ALLOYS
Authors: ONG CHUN YEE AARON
Keywords: electrodeposition, nickel, tungsten, nanocrystalline, amorphous, hallpetch
Issue Date: 3-May-2016
Source: ONG CHUN YEE AARON (2016-05-03). ELECTRODEPOSITION OF NI-W AMORPHOUS AND NANOCRYSTALLINE ALLOYS. ScholarBank@NUS Repository.
Abstract: This project explores the Ni-W electrodeposition process while testing a new buffered pH solution, using the findings to investigate the Hall-Petch breakdown and deposition mechanism, or “induced codeposition”. Our new solution resulted in thicker, homogeneous deposits, as well as good quality deposits from acidic conditions with higher tungsten contents, never reported before. A higher tungsten content was associated with finer grain sizes, and an unexpected increase in hardness was observed above 14 at% tungsten. For amorphous microstructures, an increase in tungsten content was associated with increasing hardness, similar to solid solution strengthening in conventional crystalline metals but not observed before. Of the proposed deposition mechanisms, the mechanism involving a complex between citrate, tungstate and nickel ions shows the most promise in explaining these observations and relationships.
URI: http://scholarbank.nus.edu.sg/handle/10635/129152
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