Influence of Additives on Electrodeposition of Metals from Deep Eutectic Solvents

284 Pages·2012·12.05 MB·English

Influence of Additives on Electrodeposition of Metals from
Deep Eutectic Solvents

Thesis submitted for the degree of
Doctor of Philosophy
At the University of Leicester

By

Hasan Fisal AL-Esary
Department of Chemistry
University of Leicester

November 2017
Abstract
Influence of Additives on Electrodeposition of Metals from Deep Eutectic
Solvents
Hasan Fisal AL-Esary
University of Leicester 2017
In metal electroplating processes, additives are normally added to the plating bath to
improve the physical and mechanical properties of the coating such as brightness,
roughness, thickness, hardness and resistance to corrosion. The effects of additives on
the electrodeposition of metals from aqueous solution have been extensively
investigated. However, very few studies have considered the effects of additives on the
electrodeposition of metals from ionic liquids (deep eutectic solvents).
This work has shown that ethylenediaminetetraacetic acid disodium salt dihydrate
(EDTA), sodium iodide (NaI), boric acid (BA) and 5,5-dimethylhydantoin (DMH) as
additives can be used to modify the Cu deposit morphology obtained from a 1:2 ChCl:
ethylene glycol-based liquid (Ethaline 200) on a mild steel substrate. It was found that
NaI significantly influenced the morphology of the Cu deposit, achieving a bright and
thick Cu deposition. The effects of nicotinic acid (NA), boric acid (BA) and
benzoquinone (BQ) on Zn deposit morphology from Ethaline 200 were also shown, and
for the first time a bright zinc coating has been achieved on a copper substrate when NA
was used.
The feasibility of Zn-Ni alloy deposition from Ethaline 200-based deep eutectic solvents
has been investigated in the absence and presence of boric acid and sodium bromide. It
was found for the first time that a successful bright Zn-Ni alloy coating from Ethaline
200 can be produced in the presence of boric acid and NaBr as additives. Moreover, the
effects of current density, temperature and concentration of Zn species on
electrodeposition of Zn-Ni alloy from Ethaline 200 in the presence of both boric acid
and NaBr have been studied.
The last part of this work was to look at the effects of methyl nicotinate (MN) on the
electrodeposition of Al from 1-ethyl-3-methylimidazolium chloride/AlCl3 and 1-butyl-
3-methylimidazolium/AlCl as classical ionic liquids, and (1.5:1) AlCl :acetamide,
3 3
(1.5:1) AlCl :N-methylacetamide and (1.5:1) AlCl :N,N-dimethylacetamide as deep
3 3
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eutectic solvents. A mirror Al coating has been achieved on a copper substrate from
both conventional ionic liquids as a result of using methyl nicotinate as an additive. MN
has improved the morphology of Al deposited from (1.5:1) AlCl :acetamide-based
3
liquids and, furthermore, MN has been used to refine the grain size of the Al coating
achieved from (1.5:1) AlCl :N,N-dimethylacetamide as a deep eutectic solvent.
3

ii
Conference contributions
(1) Talks:
1. Hasan AL-Esary, K. S. Ryder and A. P. Abbott, Effect of Additives on Zinc
Electrodeposition from Novel Ionic Liquid Solvent, Midlands Electrochemistry
Group (MEG), 22nd June 2015, University of Warwick, Coventry, UK.
2. Hasan AL-Esary, K. S. Ryder and A. P. Abbott, Electrodeposition of Zn-Ni
Alloy from Deep Eutectic Solvents, Electrochem Conference, 17th -19th August
2016, University of Leicester, Leicester, UK.
3. Hasan AL-Esary, K. S. Ryder and A. P. Abbott, Electroplating of Aluminium
from Novel Ionic Liquids, Electrochem Conference, 10th -12th September 2017,
University of Birmingham, Birmingham, UK.
4. Karl Scott Ryder, Robert Hillman, Emma J.R. Palin, Hasan Al-Esary,
Characterisation of Metal Deposition and Metal Dissolution Processes in Deep
Eutectic Solvents Using Electrochemical, Gravimetric and Neutron Scattering
Methods, 232nd ECS Conference (October 1-6, 2017) National Harbor,
Washington, USA.

(2) Posters:
1. Hasan AL-Esary, K. S. Ryder and A. P. Abbott, Influence of Nicotinic Acid on
Electrodeposition of Zinc from Deep Eutectic Solvents, Department of
Chemistry Postgraduate Research Day, 14th April 2015, University of Leicester,
Leicester. UK.
2. Hasan AL-Esary, K. S. Ryder and A. P. Abbott, Influence of Nicotinic Acid on
Electrodeposition of Zinc from Deep Eutectic Solvents, Electrochem
Conference, 13th -15th September 2015, Durham University, Durham, UK.
3. Hasan AL-Esary, K. S. Ryder and A. P. Abbott, Electrodeposition of Zn-Ni
Alloy from Deep Eutectic Solvents, Midlands Electrochemistry Group (MEG),
25nd May 2016, University of Leicester, Leicester. UK.
4. Hasan AL-Esary, K. S. Ryder and A. P. Abbott, Electroplating of Aluminium
from Novel Ionic Liquids, Midlands Electrochemistry Group (MEG), 26nd April
2017, University of Nottingham, Nottingham. UK.
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5. Hasan AL-Esary, K. S. Ryder and A. P. Abbott, Electroplating of Aluminium
from Novel Ionic Liquids, Electrochem Conference, 10th -12th September 2017,
University of Birmingham, Birmingham, UK.
6. Hasan AL-Esary, K. S. Ryder and A. P. Abbott, Electrodeposition of bright Zn-
Ni Alloy from Deep Eutectic Solvents, EMDoc PGR Conference, 13th
September 2017, University of Nottingham, Nottingham. UK.
7. Hasan AL-Esary, K. S. Ryder and A. P. Abbott, Influence of Nicotinic Acid on
Electrodeposition of Zinc from Deep Eutectic Solvents, 1st Iraqi Student
Conference, 29th September 2017, University of Sheffield, Sheffield, UK

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Statement

The work presented in this thesis for the degree of Ph.D. entitled “Influence of Additives
on Electrodeposition of Metals from Deep Eutectic Solvents”. The experimental work in
this thesis has been carried out by the author in the Department of Chemistry at the
University of Leicester between September 2013 and September 2016. The work has
not been submitted, and is not presently submitted, for any other degrees at this or any
other university.

Signed.................................................
Date...............................................

v
Acknowledgements
It is a pleasure to thank the people who have made this dissertation possible. First and
foremost I would like to thank my supervisor, Professor Karl Ryder, for his amazing
ideas, encouragement, support, guidance and insightful comments throughout my PhD.
I would also like to thank Professor Andy Abbott for giving me useful insights, advice
and for his help. It is also a pleasure to thank all the group members, especially Andy
Ballantyne, Rob Harris, Rachel and Alex for helping and providing assistance. Thanks
also to Virginia for helping and advising me on setting up my experiments, especially in
the electrodeposition of Aluminium. I am also thankful to the administrative and
workshop staff of the department for their cooperative attitude and assistance. I would
like to thank Mr Graham Clark, who helped me to use the scanning electron
microscope.
I would like to thank my colleagues and PhD students, some of who have graduated and
some are about to graduate. They are: Mohommade Qasem, Hani Ismail, Jalil Kareem
Jamil Juma, Shannon Stodd, Wrya Karim, Fikrat and Salih Cihangir. Everyone in the
department of chemistry and engineering has helped me at some point or other, so thank
you to you all.
Unquestionably, this would have never been possible without the love and patience of
my family members especially my parents. I would like to reserve special thanks to my
loving wife, Rawaa, for her love, support, and encouragement during times of patience
and strength during all these years. I dedicate this thesis to you, my family.
Finally, I would like to thank the Iraqi Ministry of Higher Education and Scientific
Research and University of Kerbala, Iraq, for the financial support required to complete
this project.

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Dedication

I would like to dedicate this thesis to my father, who did not forget me during my
studies and pushed me into the way of success, and also I would like to dedicate my
thesis to my mother, who did not forget me by supplication to God.

Hasan Fisal AL-Esary
Leicester, 2017

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Thesis contents

Abstract i
Conference contributions iii
Statement v
Acknowledgements vi
Dedication vii
Thesis contents viiiii
List of abbreviations xv

Chapter 1: Introduction
1.1 Electroplating 3
1.2 Ionic liquids 4
1.2.1 Synthesis of ionic liquid 8
1.2.2 Electrodeposition from ionic liquids 10
1.3 Deep eutectic solvents (DESs) 12
1.3.1 Properties of deep eutectic solvents 13
1.3.1.1 Phase behaviour 13
1.3.1.2 Density, viscosity and conductivity 15
1.3.1.3 Hole theory 17
1.3.2 Electrodeposition from deep eutectic solvents 17
1.3.2.1 Copper plating 19
1.3.2.2 Zinc plating 20
1.3.2.3 Nickel plating 21
1.3.2.4 Aluminium plating 22
1.3.3 Alloy plating 24
1.3.3.1 Zn alloys 25
1.4 Role of additives on electrodeposition of metals 27
1.4.1 Effects of additives on cathodic deposits 28
1.4.1.1 Grain refinement of the deposit 28
1.4.1.2 The polarization of the cathode 29
1.4.1.3 Incorporation of additives in the deposit 30
viii
1.4.1.4 The change of orientation of crystals in the deposit 31
1.4.2 Mechanisms of levelling and brightening 32
1.4.2.1 Levelling 32
1.4.2.2 Brightening 33
1.5 Electrocrystallisation 34
1.5.1 Electrical double layer 36
1.5.2 Concentration profile layer 37
1.5.3 Fluid velocity layer 38
1.6 Formation of metal phase 38
1.6.1 Nucleation 38
1.6.2 Growth 39
1.7 Aim of this project 40
1.8 References 42

Chapter 2: Experimental Procedures
2 Introduction 58
2.1 Part I (Electrochemistry and principle of techniques) 58
2.1.1 Electrochemistry 58
2.1.1.1 Electrode reactions and mechanisms of electron transfer 58
2.1.1.2 Cyclic voltammetry 59
2.1.2 Mass transport 62
2.1.3 Quartz crystal microbalance EQCM 63
2.1.4 Surface analysis techniques 65
2.1.4.1 Scanning electron microscopy (SEM) 65
2.1.4.2 Atomic force spectroscope (AFM) 66
2.1.4.3 X-Ray diffraction (XRD) 67
2.2 Part II (experimental) 68
2.2.1 Materials 68
2.2.2 Preparation of solutions 69
2.2.2.1 Deep eutectic solvents 69
2.2.2.2 Metal salts solutions 69
2.2.2.3 Additive solutions 70
2.2.3 Physical properties 70
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