DES_NIAdditives_Ryder_Resubmission.pdf (3.4 MB)

Bright metal coatings from sustainable electrolytes: the effect of molecular additives on electrodeposition of nickel from a deep eutectic solvent

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journal contribution
posted on 17.01.2018, 11:59 by Andrew P. Abbott, Andrew Ballantyne, Robert C. Harris, Jamil A. Juma, Karl S. Ryder
Organic and inorganic additives are often added to nickel electroplating solutions to improve surface finish, reduce roughness and promote uniform surface morphology of the coatings. Such additives are usually small molecules and often referred to as brighteners or levellers. However, there have been limited investigations into the effect of such additives on electrodeposition from ionic liquids (ILs) and deep eutectic solvents (DESs). Here we study the effect of four additives on electrolytic nickel plating from an ethyleneglycol based DES; these are nicotinic acid (NA), methylnicotinate (MN), 5,5-dimethylhydantoin (DMH) and boric acid (BA). The additives show limited influence on the bulk Ni(ii) speciation but have significant influence on the electrochemical behaviour of Ni deposition. Small concentrations (ca. 15 mM) of NA and MN show inhibition of Ni(ii) reduction whereas high concentrations of DMH and BA are required for a modest difference in behaviour from the additive free system. NA and MN also show that they significantly alter the nucleation and growth mechanism when compared to the additive free system and those with DMH and BA. Each of the additive systems had the effect of producing brighter and flatter bulk electrodeposits with increased coating hardness but XRD shows that NA and MN direct crystal growth to the [111] orientation whereas DMH and BA direct crystal growth to the [220] orientation.
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Citation

Physical Chemistry Chemical Physics, 2017, 19 (4), pp. 3219-3231

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Chemistry

Version

AM (Accepted Manuscript)

Published in

Physical Chemistry Chemical Physics

Publisher

Royal Society of Chemistry

eissn

1463-9084

Acceptance date

05/01/2017

Copyright date

2017

Available date

17/01/2018

Publisher version

http://pubs.rsc.org/en/Content/ArticleLanding/2017/CP/C6CP08720E#!divAbstract

Language

en

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