evaluation of nickel electroless plating on mild

EVALUATION OF NICKEL ELECTROLESS PLATING ON MILD STEEL

MOHD RIDZWAN BIN ADNAN

Thesis submitted in fulfillment of the requirements

for the award of the degree of Bachelor of Mechanical Engineering

Faculty of Mechanical Engineering

UNIVERSITI MALAYSIA PAHANG

DECEMBER 2010

ii

UNIVERSITI MALAYSIA PAHANG

FACULTY OF MECHANICAL ENGINEERING

I certify that the thesis entitled “Evaluation of Nickel Electroless Plating on Mild Steel”

is written by Mohd Ridzwan Bin Adnan. I have examined the final copy of this thesis

and in my opinion; it is fully adequate in terms of scope and quality for the award of the

degree of Bachelor of Mechanical Engineering. I herewith recommend that it be

accepted in fulfillment of the requirements for the degree of Bachelor of Mechanical

Engineering.

LUQMAN HAKIM BIN AHMAD SHAH

Examiner: Signature

iii

SUPERVISOR’S DECLARATION

I hereby declare that I have checked this project and in my opinion, this project is

adequate in terms of scope and quality for the award of the degree of Bachelor of

Mechanical Engineering.

Signature:

Name of Supervisor: DAYANGKU NOORFAZIDAH BINTI AWANG SH’RI

Position: LECTURER

Date: 06 DECEMBER 2010

iv

STUDENT’S DECLARATION

I hereby declare that the work in this project is my own except for quotations and

summaries which have been duly acknowledged. The project has not been accepted for

any degree and is not concurrently submitted for award of other degree.

Signature:

Name: MOHD RIDZWAN BIN ADNAN

ID Number: MA08007

Date: 06 DECEMBER 2010

vi

ACKNOWLEDGEMENTS

I am grateful and would like to express my sincere gratitude to my supervisor

Mrs. Dayangku Noorfazidah binti Awang Sh’ri for her germinal ideas, invaluable

guidance, continuous encouragement and constant support in making this research

possible. She has always impressed me with her outstanding professional conduct, her

strong conviction for science and material, and her belief that a degree program is only a

start of a long-time learning experience. I appreciate her consistent support from the

first day I applied to graduate program to these concluding moments. I am truly grateful

for her progressive vision about my training in science and material, her tolerance of my

naïve mistakes, and her commitment to my future career. I also sincerely thank her for

the time spent proofreading and correcting my many mistakes.

My sincere thanks go to all my labmates and members of the staff of the

Mechanical Engineering Department, UMP, who helped me in many ways and made

my stay at UMP pleasant and unforgettable. Many special thanks go to member science

and material research group for their excellent co-operation, inspirations and supports

during this study.

I acknowledge my sincere indebtedness and gratitude to my parents for their

love, dream and sacrifice throughout my life. I also gratefully acknowledge the

assistance of everybody who helped in the execution of this project in UMP. Special

thanks to Mr. Basirul Subha Bin Alias as the PSM coordinator, who has given some

advice and share his knowledge on this PSM. I would like to acknowledge their

comments and suggestions, which was crucial for the successful completion of this

study.

vii

ABSTRACT

Nickel electroless plating on mild steel is carried out by a chemical reaction and without

the use of an external source of electricity. In nickel electroless plating, nickel chloride

will come as a metallic salt and is reduced by using Sodium hypophosphite as the

reducing agent to nickel metal, which then is deposited on the mild steel. In this

experiment, the effect of solution concentration on thickness and mechanical properties

of nickel plating on mild steel using electroless plating process was investigated. The

solutions used in this experiment were Sodium hypophosphite and nickel chloride.with

varying concentration. Electroless plating were done for 30 days. Then the surface

structure and morphology nickel plating was evaluated using scanning electron

microscopy (SEM), Optical Microscope while its hardness was evaluated using Vickers

hardness test. In electroless plating, anode is the movements of negative ions toward the

positive electrode and the mild steel as the cathode because the movement of positive

ions toward the negative electrode. Electroless plating found the coating thickness by

effected of percentage of concentration of solution, effect of thickness of coating to the

mechanical properties and anode and cathode weight loss in electroless plating. The size

of sample specimen is 0.05 m of length, 0.03 m of width and 0.001 m of thickness for

both of mild steel and nickel sheet metal. The machine that was applied in the

experiment were, shearing machine to cut the mild steel into size, drilling machine to

make a hole to the surface of mild steel and nickel, micro vickers hardness test machine

to get a mechanical properties behavior to mild steel after electroless plating and

scanning electron microscopy (SEM) to get the microstructure observation of sample

after electroless plating. The highest coating thickness is at 252 µm corresponding to

percentage of concentration solution of 22.2 % at sample 8 followed by 19.4 %, 16.7 %,

13.9 %, 11.1 %, 8.3 %, 5.6 %, and 2.8 % for sample 7, 6, 5, 4, 3, 2, and 1. When the

percentage of concentration of solution is increase, the hardness value of mild steel is

decrease while the coating thickness increases. So, the grain size of microstructure will

increase while increase the percentage of concentration of solution.

viii

ABSTRAK

Penyaduran nikel kurang elektro pada keluli tulen (mild steel) dilakukan oleh reaksi

kimia dan tanpa menggunakan sumber tenaga elektrik sebagai agen luar. Dalam

penyaduran nikel kurang elektro, Nikel klorida akan datang sebagai garam metalik dan

dikurangkan dengan menggunakan Natrium hipofosfit sebagai agen pengurangan untuk

logam nikel, yang kemudian disimpan dalam keluli tulen. Pada eksperimen ini,

pengaruh konsentrasi larutan terhadap ketebalan dan sifat mekanik pelapisan nikel pada

keluli tulen dengan menggunakan proses penyaduran atau pelapisan kurang elektro

diselidiki. Serbuk larutan yang digunakan dalam penyaduran ini adalah Natrium

hipofosfit dan nikel klorida dengan pelbagai kepekatan. Penyaduran kurang elektro

dilakukan selama 30 hari. Kemudian struktur permukaan dan morfologi penyaduran

nikel dinilai menggunakan Pengimbasan Mikroskop Elektron (SEM), Mikroskop

optikal manakala kekerasannya dinilai dengan menggunakan ujian kekerasan Vickers.

Dalam penyaduran kurang elektro, Anod adalah pergerakan ion negatif terhadap

elektrod positif dan keluli tulen sebagai katod kerana pergerakan ion positif terhadap

elektrod negatif. Hal ini di sebabkan ketebalan lapisan mempengaruhi peratusan

kepekatan larutan, pengaruh ketebalan lapisan terhadap sifat mekanik dan kehilangan

berat pada katod dan katod pada penyaduran kurang elektro. Saiz sampel spesimen

adalah 0.05 m panjang, 0.03 m lebar dan 0.001 m tebal untuk kedua keluli tulen dan

kepingan logam nikel. Mesin yang digunakan dalam eksperimen adalah, mesin

pemotong untuk memotong keluli tulen mengikut ukuran, mesin gerudi untuk membuat

lubang pada permukaan keluli tulen dan nikel, mesin ujian kekerasan vicker mikro

untuk mendapatkan perilaku sifat mekanik untuk keluli tulen selepas penyaduran kurang

elektro dan Pengimbasan Mikroskop Elektron (SEM) di gunakan untuk mendapatkan

pemerhatian mikrostruktur pada sampel selepas penyaduran kurang elektro. Ketebalan

lapisan tertinggi pada 252 µm sesuai dengan peratusan kepekatan larutan sebanyak 22,2

% pada sampel 8 diikuti oleh 19.4 %, 16,7 %, 13,9 %, 11,1 %, 8,3 %, 5,6 %, dan 2.8 %

untuk sampel 7, 6, 5, 4, 3, 2, dan 1. Apabila peratusan konsentrasi larutan bertambah,

nilai kekerasan untuk keluli tulen akan berkurang sementara meningkatkan ketebalan

lapisan. Jadi, saiz butiran mikro akan meningkat sementara meningkatnya peratusan

kepekatan larutan.

ix

TABLE OF CONTENTS

Page

APPROVAL DOCUMENTS ii

SUPERVISOR’S DECLARATION iii

STUDENT’S DECLARATION iv

DEDICATION v

ACKNOWLEDGEMENTS vi

ABSTRACT vii

ABSTRAK viii

TABLE OF CONTENTS ix

LIST OF TABLES xiii

LIST OF FIGURES xiv

LIST OF SYMBOLS xvii

LIST OF ABBREVIATIONS xviii

CHAPTER 1 INTRODUCTION

1.1 Project Background 1

1.2 Problem Statement 2

1.3 Project Objectives 2

1.4 Project Scope of Work 2

1.5 Significance of The Study 3

1.6 Project Flow Diagram 5

1.7 Project Flow Details 6

1.8 Project Task (Gantt Chart) 7

CHAPTER 2 LITERATURE REVIEW

2.1 Introduction 8

2.2 Current Existing Electroless Plating Sample 9

2.2.1 Origin of Electroless Nickel, History and Basic Theory 9

x

2.2.2 Interpretation of Electroless Plating 10

2.2.3 Electroplating Process 11

2.2.4 Coating Technologies 14

2.2.5 Mechanical Properties of Nickel Electroless Plating 15

2.3 Parameter Included In Nickel Electroless Plating 21

2.3.1 Types of Chemical 21

2.3.2 Type of Material 23

2.3.3 Common Material Plated 23

2.4 Applications of Electroless Nickel Plating 25

2.5 Pretreatment of Parts for Electroless Nickel Plating 26

2.5.1 Advantages of Electroless Nickel Plating 26

2.5.2 Disadvantages of Electroless Nickel Plating 27

2.6 Time Uses In Electroless Nickel Plating 28

2.6.1 For Corrosion Resistance 28

2.6.2 For Wear Resistance in Hard to Reach Areas 28

2.7 Types of Electroless Nickel Plating 28

2.7.1 Nickel Phosphorus Baths 28

2.7.2 Nickel-Boron Baths 29

2.7.3 Polyalloys 30

2.7.4 Composite Coatings 30

2.8 Scanning Electron Microscopy (SEM) 31

2.9 Conclusion 32

CHAPTER 3 RESEARCH METHODOLOGY

3.1 Introduction 33

3.2 Process Flow Diagram 35

3.3 Specimen Preparations 36

3.3.1 Type of Metal that were Used 36

3.3.2 Size of Sheet Metal 37

3.3.3 Quantity Needed in Experiment 38

3.4 Items of Solution 39

3.4.1 Type of Solution that were Used 39

3.4.2 Concentration of Solution 40

3.4.3 Preparation of Solution 41

3.5 Apparatus and Instrument Preparation 41

3.5.1 Apparatus that Apply 41

xi

3.5.2 Instrument Preparations 43

3.6 Overall Experiment Configuration 44

3.7 Design of Experiment (DOE) 46

3.7.1 General Flow of Experiment 46

3.7.2 Step-by-Step of Procedure 47

3.8 Conclusion 57

CHAPTER 4 RESULTS AND DISCUSSION

4.1 Introduction 58

4.2 Before Electroless Plating Process 59

4.2.1 Important Aspect 59

4.2.2 Weight Measurement Process 60

4.3 Anode and Cathode Weight Loss in Electroless Plating 62

4.4 Material Characterization 65

4.5 Microstructure Observation 66

4.5.1 Microstructure Observation for Mild Steel After

Electroless Plating Process

66

4.5.2 Nickel Coating Surface Morphology 67

4.5.3 Grain Boundaries Structure of Mild Steel on The Surface

after Electroless Plating Process

69

4.6 Evaluation of Effect of Percentage of Concentration 70

4.6.1 Effect of Percentage of Concentration of Solution to the

Thickness of Coating

70

4.6.2 Effect of Coating Thickness to the Mechanical properties 77

CHAPTER 5 CONCLUSION AND RECOMMENDATIONS

5.1 Introduction 79

5.2 Conclusions 79

5.3 Recommendation 80

REFERENCES 82

APPENDIXS 84

A Data of important aspect before electroless nickel plating process 84

B Data for measuring the mass of powder before electroless plating

process

85

xii

C Data for mixture of distilled water + sodium hypophosphite +

nickel chloride before electroless plating process

86

D Data for weight after electroless plating process 88

E Data for comparing the reading of Mild Steel and Nickel before

and after electroless plating process

89

F Data for Reading of Mild steel by using Micro Vickers Hardness

Test (HV)

90

G

(a) –(h)

Metallurgical microscope grain boundary structure for specimen 1

until specimen 8

91

H Overall experiment setup for electroless plating process 99

xiii

LIST OF TABLES

Table No. Title Page

2.1 Coating processes used to protect functional surfaces 15

2.2 Properties of sodium phosphinate 22

3.1 The experiment’s essentials in electroless plating 47

4.1 The sample preparation of electroless plating process 59

4.2 Measuring the weight of powder (Sodium Hypophosphite &

Nickel Chloride

60

4.3 Amounts for each sample specimen before electroless plating

process

61

4.4 Comparing the weight of Mild Steel and Nickel before and after

Electroless plating

62

4.5 The percent of weight loss of mild steel and nickel 63

4.6 The thickness of coating with fix of time to plating (30 day) 75

4.7 Reading of mild steel by using micro vickers hardness test (HV) 77

5.1 Etching used for low carbon steel 81

6.1 Data of important aspect before electroless nickel plating process 84

6.2 Data for measuring the mass of powder before electroless plating

process

85

6.3 Data for mixture of distilled water + sodium hypophosphite +

nickel chloride before electroless plating process

86

6.4 Data for weight after electroless plating process 88

6.5 Data for comparing the reading of Mild Steel and Nickel before

and after electroless plating process

89

6.6 Data for Reading of Mild steel by using Micro Vickers Hardness

Test (HV)

90

xiv

LIST OF FIGURES

Figure No. Title Page

1.1 Project flow diagrams 5

1.2 Project gantt chart 7

2.1 Examples of electroformed Microstructures 10

2.2 Schematic of electroplating process 12

2.3 Order in which dissimilar metals produce electromotive-force

(Galvanic) series

13

2.4 Chemical reaction of sodium phosphinate 22

2.5 Evo 50 type of common SEM machine in industries 31

2.6 Schematic diagram of SEM 32

3.1 Process flow diagram 35

3.2 Sample of mild steel sheet metal 36

3.3 Sample of nickel sheet metal 37

3.4 Sketching for Size of specimen 38

3.5 Size of specimen 38

3.6 Sample powder of sodium hypophosphite and

its colour

39

3.7 Sample powder of nickel chloride and its colour 40

3.8 Sample of 500ml glass beaker 42

3.9 Sample of commonly electronic wire 42

3.10 Sample of stick 43

3.11 Evo 50 type of Common SEM machine 44

3.12 Sample 5 during electroless plating 44

3.13 Schematic diagram of nickel electroless plating on mild steel 45

xv

3.14 General flow of experiment 46

3.15 Cutting process 48

3.16 Drilling process 49

3.17 Filing process 49

3.18 Measurement process 50

3.19 The specimens before added to the distilled water 51

3.20 The specimens after added to the distilled water 51

3.21 Vickers hardness test (HV) 52

3.22 Mounting process 53

3.23 Grinding and polishing process 54

3.24 Etching process 55

3.25 Etching time and place to etching process 55

3.26 Observation process by using metallurgical microscope 56

3.27 Observation process by using optical microscope 56

4.1 The weighted loss of mild steel and nickel after electroless plating 64

4.2 The sample 8 of mild steel in electroless plating process, (a)

before; (b) after

65

4.3 The sample of microstructure observation after electroless plating

for sample 1

66

4.4 SEM surface morphology of nickel electroless plating 67

4.5 The surface of mild steel by using metallurgical microscope 68

4.6 Difference micrographs showing grain boundaries 70

4.7 SEM coating surface thickness (material; mild steel): (a)

Specimen 1 (1780x); (b) Specimen 2 (1960x)

71

4.8 SEM coating surface thickness (material; mild steel): (c)

Specimen 3 (1280x); (d) Specimen 4 (555x)

72

xvi

4.9 SEM coating surface thickness (material; mild steel): (e)

Specimen 5 (810x); (f) Specimen 6 (1000x)

73

4.10 SEM coating surface thickness (material; mild steel): (g)

Specimen 7 (720x); (h) Specimen 8 (570x)

74

4.11 Effect of percentage of concentration of solution on coating

thickness

76

4.12 Effect of coating thickness to the hardness mechanical properties

of mild steel

78

6.1 Metallurgical microscope grain boundary structure for specimen 1 91








6.9 Before Mix with Distilled water 99

6.10 After Mix with Distilled water and ready to electroless plating

process

99

xvii

LIST OF SYMBOLS

HV Micro Vickers Hardness

e Electron

µ Micron

Vpn plated

g/cm3 Density

cal-

cm/sec/°C

Heat of conductivity

°C Temperature

NiP3 Nickel phosphide

Mpa Mega Pascal

NaPO2H2 Sodium hypophosphite

NiCl2 Nickel Chloride

VHN Composite coating

m Distance

mol/L Concentration of solution

ml Volume

% Percentage

g weight

s time

xviii

LIST OF ABBREVIATIONS

ASTM American Society for Testing and Materials

CVD Chemical vapour deposition

DOE Design of experiment

EN Electroless nickel

EQN Equation

FYP Final year project

NC Nickel chloride

PSM Projek sarjana muda

PVD Pysical vapour deposition

SEM Scanning electron microscopy

SH Sodium hypophosphite

UMP Universiti Malaysia Pahang

1

CHAPTER 1

INTRODUCTION

1.1 PROJECT BACKGROUND

This project title is Evaluation of Nickel Electroless Plating on Mild Steel. This

experiment is intended to see the chemical reaction of mild steel by using chemicals that

differs in kind of effect to the coating thickness. Electroless plating is an autocatalytic

process where the substrate develops a potential when it is dipped in electroless solution

called bath which contains a source metal of metallic ions, reducing agent, stabilizer and

others. Due to the developed potential, both positive and negative ions are attracted

towards the substrate surface and release their energy through charge transfer process.

Each process parameter has its specific role on the process and influences the process

response variables. Temperature initiates the reaction mechanism which controls the

ionization process in the solution and charge transfer process from source to substrate.

In addition to this, the substrate is activated before dipping into the electroless bath and

sensitized to initiate the charge transfer process. Actually in electroless metal deposition

process, no external current supply is required to deposit material on a substrate.

Electroless deposition has the advantages of simplicity and feasibility over other

processes. The amorphous boron is introduced to improve the adherence between

coating and the substrate besides improving properties, like wear resistance, hardness,

corrosion resistance and surface roughness. The applications of electroless nickel have

been reported in many industries, like petroleum, chemical, plastics, optics, aerospace,

nuclear, electronic devices, computer, and printing because of its excellent corrosion

and wear resistance properties. This experiment should be carried out at various

2

conditions of temperature and environments, and the same time to see the reaction

simultaneously in mild steel.

1.2 PROBLEM STATEMENT

For this evaluation, current process of nickel electroless plating on mild steel is

considered to be around 20 to 40 days (Rossi, 2003) to get some of coating on material.

The experiment was divided into 8 unit. It was conducted with constant time to get

different thicknesses for each of the electroless plating. In addition, different type of

material to coat has a different of microstructure after electroless plating on market. One

of the most effects to focus during screening the surface is morphology test by using

SEM (scanning electron microscope). All specimens are rectangular in shape with 0.05

m x 0.03 m x 0.001 m in size. But for the future improvement during electroless plating

process, it required to use various types of shape on specimen with various time coating.

1.3 PROJECT OBJECTIVES

Basically this project is based on these two objectives:

• To evaluate the effect of nickel electroless plating on mild steel.

• To study the result of electroless plating by using morphology analysis on mild

steel.

1.4 PROJECT SCOPE OF WORK

In this study, the experiment or analysis test will be held in the Material

Laboratory and the area of UMP. This process is carried out by a chemical reaction and

without the use of an external source of electricity. The scopes of the study are as

follows:-

a) For the test in the laboratory, the Sodium hypophosphite is consider to use as the

reducing agent to nickel metal and nickel chloride as a metallic salt, which then

is deposited on the work piece. It is mainly used for electroless nickel plating

3

and with this method, a durable nickel-phosphorus film can coat objects with

irregular surfaces, and can widely be used ionics, aviation and the petroleum

field.

b) Use the nickel metal as Anode (positive terminal) and a piece of mild steel as a

Cathode (negative terminal) in Sodium hypophosphite.

c) Plating area will conduction in Material Laboratory at UMP by following a

parameter that needed.

d) Parameters that will be analyzed is a constant coating time during conducts the

electroless plating, concentration of solution (contents, mol and pH) and types of

solution that use during electroless plating process (fix and constant).

1.5 SIGNIFICANCE OF THE STUDY

Electroless nickel (EN) plating is a chemical reduction process that depends

upon the catalytic reduction process of nickel ions in an aqueous solution (containing a

chemical reducing agent) and the subsequent deposition of nickel metal without the use

of electrical energy. Thus in the Electroless nickel plating process, the driving force for

the reduction of nickel metal ions and their deposition is supplied by a chemical

reducing agent in solution. This driving potential is essentially constant at all points of

the surface of the component, provided the agitation is sufficient to ensure a uniform

concentration of metal ions and reducing agents. The electroless deposits are therefore

very uniform in thickness all over the part’s shape and size. The process thus offers

distinct advantages when plating irregularly shaped objects, holes, recesses, internal

surfaces, valves, threaded parts, and so forth.

Electroless as autocatalytic nickel coating provides a hard, uniform, corrosion-,

abrasion-, and wear-resistant surface to protect machine components in many industrial

environments. EN is chemically deposited, making the coating exceptionally uniform in

thickness. Careful process control can faithfully reproduce the surface finish,

eliminating the need for costly machining after plating.

4

In a true electroless plating process, reduction of metal ions occurs only on the

surface of a catalytic substrate in contact with the plating solution. Once the catalytic

substrate is covered by the deposited metal, the plating continues because the deposited

metal is also catalytic. As a result, electroless plating processes are widely used in

industry to meet the end-use functional requirements and are only rarely used for

decorative purposes. Electroless plating is ideal for the salvage of miss-machined parts

& recycling worn components and it can reduce wear and corrosion. Besides, electroless

plating can be hardened on metal that using and it can change magnetic tendency of a

substrate.

Electroless nickel plating also can reduce galling and frictional resistance. It also

can be soldered easily. Other than that, Electroless Nickel provides lubricity and

functional release properties, making it ideal plating for dies, gears, and molds. It can

also be used as a cost effective measure to repair and salvage molds.

5

1.6 PROJECT FLOW DIAGRAM

Figure 1.1: Project flow diagrams

Gather information

Collection information

Analysis on Parameter

Experiment preparation

Polishing process

Immersion test

Morphology test

Analysis on physical

properties

Discussion

Documentation

End

Start

6

1.7 PROJECT FLOW DETAILS

When look on the project flow diagram, the experiment starts with gathering the

information on related of journals, magazines, books, and surfing the internet to get a

literature review and research on these title which is evaluation of Nickel Electroless

plating on Mild Steel. For this part, it focuses more to the function and the parameter

that using in the experiment. This is want to know and review of the design of

experiment and previous research in market. Alls the resources should be follow the

standard likes American Society for Testing and Material (ASTM). ASTM is an

international standards organization that develops and publishes voluntary consensus

technical standards for a wide range of materials, products, systems, and services.

After all of that, the experiment undergoes to the collect of information that

focus on the objective. In this step, the main focus is about the parameters which are

type of chemical that use, mechanical properties, the meaning of Electroless plating and

Electroplating, and previous research but the more focus is on the coating effect to the

mild steel.

For the next step, setup the experiment by following the available of parameter.

The parameter is like the type of chemical reagant, size of mild steel, quantity of mild

steel will apply and the time that will consider during experiment. In this step, all

parameters represent the number of making the experiment.

Later, on testing method, the design of experiment must be consider evaluating

of nickel electroless plating on mild steel such as a mechanical properties and

microstructure of mild steel before and after the plating process. For the microstructure

of mild steel, the thickness of coating should be considered on before and after the

experiment.

The experiment undergoes to the next step which call as analysis. For this step,

all parameter that want to evaluate must following the standard. In this step, the result

will be focus and make a comparison between actual and plan. Choose a good of result

and give a reason to the comparing. For this also focus on the parameter that follow

7

such as a hardness of mild steel before and after experiment to look about a coating. In

analysis, all result can be show on related diagram, chart, graph and table.

Finally, when all the process mentioned above is done, the material for report

writing is gathered. The report writing process will be guided by the UMP PSM report

writing guide. This process also included the presentation slide making for the mid and

final presentation of the project. The project ended after the submission of the report and

the presentation slide has been presented on the last of semester study.

1.8 PROJECT TASK (GANTT CHART)

Figure 1.2: Project gantt chart

evaluation of nickel electroless plating on mild

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