surface treatment on tungsten carbide substrate …
TRANSCRIPT
SURFACE TREATMENT ON TUNGSTEN CARBIDE SUBSTRATE PRIOR TO
HOT FILAMENT CHEMICAL VAPOUR DEPOSITION DIAMOND COATING
ENGKU MOHAMMAD NAZIM B. ENGKU ABU BAKAR
A thesis submitted in fulfilment of the
requirements for the award of the degree of
Doctor of Philosophy (Mechanical Engineering)
Faculty of Mechanical Engineering
Universiti Teknologi Malaysia
NOVEMBER 2014
brought to you by COREView metadata, citation and similar papers at core.ac.uk
provided by Universiti Teknologi Malaysia Institutional Repository
146
REFERENCES
Ahmed, W., Sein, H., Ali, N., Garcio, J. and Woodwards, R. (2003). Diamond films
grown on cemented WC-Co dental burs using an improved CVD method.
Diamond and Related Materials. 12: 1300-1306
Alam, M., D. E. P. and Tallant, D.R. (1997). Diamond deposition onto WC-6% Co
cutting tool materials : coating structure and interfacial bond strength. Thin
Solid Films. 300: 164-170.
Ali, N., Cabral, G., Titus, E., Ogwu, A.A.and Gracio, J. (2004). Characterization of
diamond adhesion on micro-grain WC-Co substrate using Brinnel identations
and micro-Raman spectroscopy. Journal of Physics: Condensed Matter. 16:
6661- 6674
Almeida, F.A., Soares, E., Fernandes, A.J.S., Sacramento, J., Silva, R.F. and
Oliveira, F.J. (2011). Diamond film adhesion onto sub-micrometric WC-Co
substrates. Vacuum. 85: 1135-1139
Amirhaghi, S. H. S. R., Plappert, E., Bajic, Z., Wood, R.J.K. and Wheeler, D.W.
(1999). Growth and erosive wear performance of diamond coatings on WC
substrates. Diamond and Related Materials. 8(2-5): 845-849
Arumugam, P. U., Malshe, A. P., and Batzer, S. A. (2006). Dry machining of
aluminum–silicon alloy using polished CVD diamond-coated cutting tools
inserts. Surface and Coatings Technology. 200: 3399-3403.
Ashfold M.N.R. and May P.W. (1997).Diamond Chemical Vapour Deposition.
Chemistry & Industry. 13: 505-508
Ashfold, M.N.R., May, P.W., and Rego, C. A. (1994). Thin Film Diamond by
Chemical Vapour Deposition Methods. Chemical Society Reviews. 23: 21-30
Avigal, Y. and Hoffmann, A. (1999). A new method for nucleation enhancement of
diamond, Diamond and Related Materials. 8(2-5): 127-131
iii
Dedicated to my beloved wife, my children and my beloved father..
iv
ACKNOWLEDGEMENT
At first thanks to ALLAH, the most gracious and the most merciful, for providing me the opportunity of doctoral study and ability to accomplish this research.
I would like to express my deepest gratitude towards my Alma matter, Assoc.
Prof. Dr. Izman Bin Sudin who nurtured me to become a researcher. Without his kind guidance, encouragement and valuable advice during the research and writing, this thesis would not be come to the light. His attention and technical expertise were key elements to my doctoral study. I am gratified in gaining from his depth knowledge in the area of materials engineering particularly in diamond coating technology, which will have a significant impact on my future career.
My appreciation also to Production Lab, Materials Engineering Lab,
especially all technicians for providing me slot within their busy schedule. My gratitude goes to Universiti Teknologi Malaysia (UTM) for sponsoring my postgraduate studies.
Finally, and most importantly, special thanks to my family specially my wife,
my son and daughters for their unconditional love, sacrifice, encouragement and support that enable me to achieve this degree.
v
ABSTRACT
Deposition of a large and uniform distribution of diamond grains with good adherent and high quality of diamond coating using chemical vapour deposition (CVD) technique is a challenge. Large diamond grains reduce the adhesion strength between the diamond coating and substrate material. The aim of this research is to develop a large and uniform distribution of grain size with high quality and good adhesion strength of diamond coating coated on WC–6wt% Co for grinding application. The research started with the determination of suitable etchant and etching time that can provide high surface roughness and lower Co content of WC substrate. The best concentration of SiC (174 µm) of 1, 5 and 10 g/l mixed with diamond (0.5 µm) powders with a concentration of 0.8 g/l for seeding was also determined. The diamond coating was performed for 30 hours using hot filament CVD unit. The field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and Raman spectra results indicate that all the coated samples have well faceted grains of (111) and (220) morphologies with high quality (>99% purity) of diamond coatings. The atomic force microscopy (AFM) shows the grain size formed was in the range of 1-6 µm with a density of above 108 grains/cm2. Sample treated with HNO3 + H2O2 for 60 seconds however had the highest adhesion strength measured by sand blasting. It is due to the lowest surface Co content and highest diamond grain density. The WC substrates etched with this etchant then seeded with 1 g/l of SiC mixed with 0.8 g/l of diamond powders was found to have diamond coating with sharp peaks with uniform height and gaps between diamond grains when observed using FESEM and AFM. This condition fulfilled the requirement for grinding application and at the same time having the highest quality (99.496% purity) and adhesion strength. To determine the grinding performance, WC grinding wheels were fabricated and treated with HNO3 + H2O2 for 60 seconds, seeded with 1 g/l of SiC mixed with 0.8 g/l of diamond powders and diamond coated for 30 hours. The grinding process was performed on WC-2wt% Co work piece using ultra-precision grinding machine at different feed rates of 0.015, 0.030, 0.045, 0.060 and 0.075 mm/min respectively. The diamond grain sharpness of the wheel was found unaffected after analysed using FESEM while the surface finish (Ra) of the work piece was finer from 0.020 µm to 0.007 µm. When compared with the commercial diamond bonded wheel grinding at 0.20 mm/min, the work piece surface finish is almost the same. However, the diamond bonded wheel was severely damaged with clogged grinding chips, broken-off and dislodged diamond particles. Meanwhile, at the diamond coated wheel, only clogging was observed. As a conclusion, mix seeding of diamond (5 µm, 0.8 g/l) and SiC (175 µm, 5 g/l) has produced good diamond coating properties for grinding application which is at par with the diamond bonded wheel.
vi
ABSTRAK
Menghasilkan salutan intan dengan saiz bijian yang besar dan seragam, daya rekatan dan kualiti yang tinggi menggunakan kaedah pengenapan wap kimia (CVD) adalah satu cabaran. Bijian intan yang besar mengurangkan daya rekatan antara salutan intan dan bahan substrat. Kajian ini bertujuan untuk menghasilkan bijian salutan intan yang besar dan seragam, daya rekatan dan kualiti yang tinggi ke atas WC-6% berat Co untuk kegunaan proses canaian. Kajian bermula dengan menentukan larutan dan masa punaran yang sesuai untuk menghasilkan kekasaran permukaan yang tinggi dan kandungan Co yang rendah pada substrat WC. Konsentrasi campuran serbuk SiC (174 µm) terbaik di antara 1, 5 dan 10 g/l di campur dengan serbuk intan (0.5 µm) dengan konsentrasi 0.8 g/l bagi tujuan pembenihan juga ditentukan. Salutan intan dilakukan selama 30 jam menggunakan unit filamen panas CVD. Analis dari mikroskop imbasan elektron pancaran medan (FESEM), pembelauan sinar-X (XRD) dan Raman spektrum menunjukkan semua salutan intan mempunyai segi bijian yang jelas dengan morfologi (111) dan (220) dan berkualiti tinggi (>99% ketulenan). Analisis mikroskopi daya atom (AFM) menunjukkan saiz bijian adalah dalam julat 1-6 µm dengan ketumpatan melebihi 108 bijian/sm2. Sampel yang dipunar dengan HNO3+H2O2 selama 60 saat, didapati mempunyai daya rekatan tertinggi bila diuji secara pembagasan pasir. Ini disebabkan oleh kandungan Co terendah serta ketumpatan bijian intan tertinggi pada permukaan substrat WC. Substrat WC yang dipunar dengan larutan ini yang kemudiannya di lakukan pembenihan dengan campuran serbuk 1 g/l SiC dan 0.8 g/l intan didapati mempunyai salutan intan dengan puncak yang tajam, ketinggian dan jarak antara bijian yang seragam apabila di analisis menggunakan FESEM dan AFM. Keadaan ini memenuhi keperluan aplikasi proses canaian dan pada masa yang sama mempunyai kualiti (99.496% ketulenan) dan kekuatan rekatan tertinggi. Bagi menguji prestasi canaian, roda pencanai WC dihasilkan, dirawat dengan HNO3+ H2O2 selama 60 saat dan dibenihkan dengan campuran serbuk 1 g/l SiC dan 0.8 g/l intan serta disalut intan selama 30 jam. Proses canaian telah dilakukan ke atas benda kerja WC-2% berat Co menggunakan mesin canai ketepatan ultra dengan kadar suapan berbeza iaitu 0.015, 0.030, 0.045, 0.060 dan 0.075mm/min. Ketajaman bijian intan didapati tidak terjejas apabila di analisis menggunakan FESEM dan kemasan permukaan (Ra) benda kerja adalah lebih halus dari asalnya 0.020 µm kepada 0.007 µm. Perbandingan canaian pada 0.20mm/min menggunakan roda intan terikat komersial menunjukkan kemasan permukaan benda kerja adalah hampir sama. Walau bagaimanapun roda komersial didapati rosak teruk dengan tatal canaian yang tersekat serta partikel intan yang pecah dan tertanggal. Sementara pada roda salutan intan, hanya tatal canaian tersekat berlaku. Sebagai kesimpulan, campuran bahan pembenihan serbuk intan (5 µm, 0.8 g/l) dan SiC (175 µm, 5 g/l) telah menghasilkan salutan intan dengan sifat yang sesuai untuk kegunaan canaian serta ia setara dengan roda canaian terikat intan.
vii
TABLE OF CONTENTS
CHAPTER TITLE PAGE
DECLARATION ii
DEDICATION iii
ACKNOWLEDGEMENT iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENTS vii
LIST OF TABLES xi
LIST OF FIGURES xiv
LIST OF SYMBOLS xxi
LIST OF ABBREVIATIONS xxiii
LIST OF APPENDICES xxiv
1 INTRODUCTION 1
1.1 Background of the Research 1
1.2 Problem Statement 3
1.3 Objectives of the Research 4
1.4 Scopes of the Research 5
1.5 Significance of the Research 6
2 LITERATURE REVIEW 7
2.1 Introduction 7
2.2 Diamond 7
2.2.1 Comparison of CVD Diamond and Single
Crystal
9
viii
2.2.2 The Application of CVD diamond 10
2.3 Cutting Tool Materials 12
2.3.1 Tungsten Carbide (WC) 12
2.3.1.1 Cobalt content in cemented Tungsten
Carbide
13
2.3.1.2 Tungsten Carbide (WC) as a
Substrate for Diamond Coating
15
2.4 Grinding 16
2.4.1 Requirements for a Grinding Wheel 17
2.5 Chemical Vapour Depostion (CVD)
18
2.5.1 Hot Filament Chemical Vapour Deposition (HFCVD)
19
2.5.2 HFCVD Diamond Nucleation and Growth 20
2.5.3 Diamond Nucleation on Metal Carbide 27
2.6 Polycrystalline Diamond Depositions on WC 28
2.6.1 Effect of Co on the Quality of Diamond Film 28
2.6.2 Importance of Diamond Nucleation Density 29
2.7 Effect of WC Substrate Surface Roughness on
Diamond Film
30
2.7.1 WC-6 wt% Co Substrate Surface Preparation 31
2.7.1.1 Second Step Pretreatment with
H2SO4 + H2O2
33
2.7.1.2 Second Step Pretreatment with
HNO3 + H2O2
34
2.7.1.3 Second Step Pretreatment with
HNO3 + HCl + H2O
35
2.8 Seeding 35
2.8.1 Seeding with Diamond Powder 35
2.8.2 Mix Seeding 37
2.9 Effect of HFCVD Parameters on Diamond Coating 39
2.9.1 Methane (CH4) concentration 39
2.9.2 Chamber Pressure 43
ix
2.9.3 Filament Temperature 47
2.9.4 Substrate Temperature 48
2.10 Summary of Literature Review 50
3 RESEARCH METHODOLOGY 52
3.1 Introduction
52
3.2 Research Approach
52
3.3 Materials
54
3.4 First Stage: Determination of the Most Suitable
Etchant
56
3.4.1 Two-Step Chemical Pretreatment 56
3.4.2 Seeding Process 57
3.4.3 Diamond Deposition Process 58
3.4.4 Characterisation of the Diamond Coating 58
3.5 Second Stage: Determination of the Composition of
Seeding Powders
62
3.5.1 Two-Step Chemical Pretreatment 62
3.5.2 Seeding Process 62
3.5.3 Diamond Deposition Process 63
3.5.4 Characterisation of the Diamond Coating 63
3.6 Third Stage: Determination of Grinding Performance
of the Diamond Coated WC Tool
64
3.6.1 In-House Fabricated Grinding Wheel 64
3.6.2 Pretreatment of Fabricated Grinding Wheel 64
3.6.3 Seeding Treatment of the Fabricated Grinding
Wheel
65
3.6.4 Diamond Deposition Process 65
3.6.5 Micro Grinding Process 66
3.6.6 Work Piece Material
67
3.6.7 Materials Characterisation of the Diamond
Coated Wheels
68
x
4 RESULTS AND DISCUSSIONS 69
4.1 Introduction 69
4.2 Effect of First Step Pretreatment on the Tungsten
Carbide Substrate Surface Roughness and Cobalt
Content
70
4.3 Effect of Second Step Pretreatment and Mixed
Seeding
72
4.3.1 Second Step Pretreatment Using H2SO4 (96%)
+ H2O2 (30%) (1:2 ratio)
73
4.3.2 Second Step Pretreatment Using HNO3(65%)
+ HCl(37%) + H2O (1:1:1 ratio)
86
4.3.3 Second Step Pretreatment Using HNO3 (65%)+
H2O2 (30%) (1:9 ratio)
100
4.3.4 Summary 113
4.4 Second Stage of Experiment
117
4.5 Third Stage of Experiment
131
4.5.1 First Part of Grinding 132
4.5.2 Second Part of Grinding 138
5 CONCLUSIONS AND RECOMMENDATIONS FOR
FUTURE WORK
1143
5.1 Conclusions 143
5.2 Recommendations 145
REFERENCES 146
Appendices A-G 155-185
xi
LIST OF TABLES
TABLE NO. TITLE PAGE
2.1 Properties of CVD diamond and single crystal diamond 10
2.2 Actual and potential application of CVD diamond 11
2.3 Properties of cutting tool materials 13
3.1 Surface roughness and Co content for as-received WC
substrates
55
3.2 Summary of second-step step pretreatment process 57
3.3 Diamond deposition parameters for HFCVD machine 58
3.4 Parameters for blasting test 60
3.5 Parameter of Raman spectra analysis 60
3.6 The concentration of diamond and silicon carbide powders for the seeding process
63
3.7 Micro-grinding parameters
67
4.1 Summary of diamond grain size and density of samples treated for 5, 10 and 15 seconds in H2SO4(96%) + H2O2(30%) solution
79
4.2 Summary of the diamond film surface roughness coated onWC substrate treated with H2SO4(96%) + H2O2(30%) for 5, 10 and 15 seconds
82
4.3 Raman spectra data and analysis 84
xii
4.4 The results of the blasting test conducted on the diamond coated WC samples treated with H2SO4(96%) + H2O2(30%) for 5 ,10 and 15 seconds
86
4.5 Results of diamond grain size and density based on AFM of samples treated for 3, 6 and 9 minutes
93
4.6 Atomic force microscope (AFM) surface roughness results of diamond coated on WC substrate treated with HNO3(65%) + HCl(37%) + H2O solution for 3, 6 and 9 minutes
95
4.7 Raman spectra data and analysis of diamond films coated on WC samples treated with HNO3(65%) + HCl(37%) + H2O for 3, 6 and 9 minutes
97
4.8 Results of the blasting test conducted on the dimoand coated WC samples treated with HNO3(65%) + HCl(37%) + H2O solution for 3, 6 and 9 minutes
99
4.9 Results of diamond grain size and density of samples chemically treated for 30, 60 and 90 seconds
106
4.10 Atomic force microscope (AFM) results of the diamond film surface roughness coated onWC substrate treated in HNO3(65%) + H2O2(30%) solution for 30, 60 and 90 seconds
109
4.11 Raman spectra data and analysis for diamond coatings on WC samples treated with HNO3(65%) + H2O2(30%) solution for 30, 60 and 90 seconds
111
4.12 The blasting test results conducted on the diamond coated WC samples treated with HNO3(65%) + H2O2(30%) solution for 30, 60 and 90 seconds
113
4.13 Summary of diamond coatings best properties coated on WC substrate treated with H2SO4 + H2O2 (15 seconds), HNO3 + HCl + H2O (6 minutes) and HNO3 + H2O2 (60 seconds)
114
4.14 Atomic force microscope AFM images analysis of the diamond coatings seeded with 0 g/l, 1 g/l, 5 g/l and 10 g/l of SiC powder
124
4.15 Surface roughness results of diamond coating seeded with 0 g/l, 1 g/l, 5 g/l and 10 g/l SiC powder
125
4.16 Raman spectrums analysis on diamond coating seeded with diamond and 0 g/l, 1 g/l, 5 g/l and 10 g/l of SiC powder
128
xiii
4.17 Results of the blasting test conducted on the diamond coated WC samples seeded with diamond and SiC powder with the concentrations of 0 g/l, 1 g/l, 5 g/l and 10 g/l
131
xiv
LIST OF FIGURES
FIGURE NO. TITLE PAGE
2.1 Transformation of hexagonal arrangement of atom in graphite to a cubic arrangement in diamond
9
2.2
diagram of carbon showing the shaded region of synthetic diamond production
9
2.3 Mechanical properties variation of tungsten carbide with normal particle size in relation to the amount of cobalt
15
2.4 Examples of two of the most common types of low-pressure CVD reactor. (a) Hot filament reactor, (b) Microwave plasma reactor
19
2.5 Schematic diagram of the chemical and physical processes occurring during diamond CVD
21
2.6 A simplified form of the Bachmann triangle C–H– O composition diagram
22
2.7 A schematic diagram of diamond growth mechanism 24
2.8 Growth process of a diamond film on a non-diamond substrate; (a) nucleation of individual crystallites (0.5 h), (b-c) termination of nucleation, and growth of individual crystallites (1h - 4h), (d) faceting and coalescence of individual crystallites, and formation of continuous film (10 h), (e-f) some crystals grow faster and swallow their neighbours during growth of continuous film (2 h- 215 h)
25
2.9 Columnar structured layer developed during continuous growth of CVD diamond. (a) Columnar morphology with increasing size of grains, (b) The crystals with the direction of fastest growth nearly perpendicular to the substrate are in favour position and will survive
26
xv
2.10 Crystal structure produced in CVD diamond growth based on α values
27
2.11 Influence of surface nucleation density on crystal morphology. (a) Scratched with diamond paste with a nucleation density of about 108 cm-2, (b) Unscratched having a nucleation density of about 104 – 105 cm-2
30
2.12 Diamond nucleation on (a) Polished Si substrate and (b) Scratched surface of WC-6 wt% Co
31
2.13 SEM images of WC-6 wt% Co substrate, (a) after grinding and (b) after etching with Murakami solution for 10 minutes
33
2.14 SEM micrographs of (i) Isotropic surface roughness of (a) 3% Co, (b) 6% Co and (c) 12% Co cemented WC, (ii) Octahedral morphology (111) of diamond on (a) 3% Co, (b) 6% Co and (c) 12% Co cemented WC
36
2.15
Relationship between diamond nucleation densities and the size of diamond particles used for seeding
37
2.16 Comparison off all properties of diamond coatings deposited at various CH4 concentrations
40
2.17 SEM images of the surface morphologies of diamond coatings deposited at (a) 1, (b) 3 and (c) 5 vol% CH4
40
2.18 Plots showing (a) average growth rate of diamond film as a function of CH4 concentration at different deposition time, (b) average grain size as a function of film thickness, (c) variation of film thickness with deposition time for four different CH4 concentrations
42
2.19 SEM micrograph of diamond nuclei for 20 min with 1 torr of pressure and ultra pure
43
2.20 Diamond coating at 20 torr, (a) Prominent diamond peak at 1332 cm-1, (b) SEM micrograph of coating for 3 hours
44
2.21 Dependence of growth rate on the temperature of the substrate surface for 3 and 20 mbar.
45
2.22 SEM micrographs of diamond coatings, deposited at (a) 3 mbar, (b) 20 mbar and (c) 50 mbar, (d) SEM micrograph of an outgrowth in the diamond coating at 50 mbar
46
2.23 Raman Spectra of CVD diamond, deposited at (a) 3 mbar and (b) 20 mbar
46
xvi
2.24 Effect filament temperature on (i) Morphology of
diamond films deposited at (a) 1700, (b) 1500 and (c) 1300OC, (ii) X-ray diffraction spectra of the deposited films shown in (i)
48
2.25
Nucleation density versus filament temperature 49
2.26
Temperature dependence on nucleation density 49
3.1
Flow chart of the overall research activities 53
3.2
WC-6 wt% Co substrate sample, (a) Actual photo, (b) Dimension of the sample
54
3.3
Surface morphology of WC substrate surface after cutting 55
3.4 Example of EDX spectrum and analysis of a cut sample 56
3.5 Atomic force microscope (AFM) unit (Park System XE100, Korea)
59
3.6 The blasting test (a) Sand blasting unit and (b) Blasting schematic diagram
60
3.7 Horiba JOBIN YVON HR 800 Raman Spectrometer 61
3.8 Tungsten Carbide grinding wheels (a) Schematic diagram of the fabricated wheel, (b) Fabricated WC wheel, and (c) Commercial diamond bonded wheel
65
3.9 Ultra-precision turning and grinding machine (Nanotech 220UPL)
66
3.10 Vertical grinding configuration 67
3.11 WC work pieces clamped into the aluminium holders
68
3.12 Surface profiler (Surfcom 5000)
68
4.1 Tungsten carbide (WC) substrate surface after Murakami’s treatment (a) FESEM image and (b) Overall EDX elemental analysis
71
xvii
4.2 Comparison of WC substrate before and after Murakami’s treatment, (a) Subsrate surface roughness, and (b) Substrate surface Co content
71
4.3 FESEM images and EDX analysis of samples treated with H2SO4(96%) + H2O2(30%) for (a) 5 sec, (b) 10 sec and (c) 15 sec
73
4.4 WC substrate surface roughness etched for 5, 10 and 15 seconds using H2SO4(96%) + H2O2(30%)
75
4.5 FESEM images and XRD spectrums of diamond film coated WC samples treated with H2SO4(96%) + H2O2(30%) for (a) 5 sec, (b) 10 sec and (c) 15 sec
76
4.6 XRD spectrums of diamond coating on WC samples treated with H2SO4(96%) + H2O2(30%) solution for (a) 5 sec (b) 10 sec and (c) 15 sec
77
4.7 Atomic force microscope (AFM) results of sample treated with H2SO4(96%) + H2O2(30%) for 5 seconds (a) distribution of diamond grain size, (b) average diamond grain size
79
4.8 Atomic Foce Microscope (AFM) 3D images of the diamond coated samples treated for, (a) 5 seconds, (b) 10 seconds, and (c) 15 seconds with H2SO4(96%) + H2O2(30%) solution
80
4.9 Surface roughness measurement using atomic force microscope (AFM) analysis of diamond coating onWC substrate chemically treated for 5 seconds
82
4.10 Raman Spectrum of the diamond coated WC samples treated with H2SO4(96%) + H2O2(30%) for 5, 10 and 15 seconds
83
4.11 FESEM images of the diamond flake-off area of the diamond coated WC samples treated with H2SO4(96%) + H2O2(30%) for (a) 5 sec, (b) 10 and (c) 15 seconds
85
4.12 FESEM images and EDX analysis of samples treated with HNO3(65%) + HCl(37%) + H2O (1:1:1 ratio) for (a) 3, (b) 6 and (c) 9 minutes
87
4.13 WC substrate surface roughness etched for 3, 6 and 9 minutes using HNO3(65%) + HCl(37%) + H2O solution
88
xviii
4.14 SEM images of diamond coating on WC samples treated in HNO3(65%) + HCl(37%) + H2O solution for (a) 3, (b) 6 and (c) 9 min
89
4.15 XRD spectrums of diamond coating on WC samples treated in HNO3(65%) + HCl(37%) + H2O solution for (a) 3, (b) 6 and (c) 9 min
90
4.16 Atomic force microscope (AFM) results of sample treated with HNO3(65%) + HCl(37%) + H2O for 3 minutes (a) distribution of diamond grain size, (b) average diamond grain size
92
4.17 AFM 3D images of diamond coating of the samples treated for, (a) 3, (b) 6 and (c) 9 minutes treated with HNO3(65%) + HCl(37%) + H2O solution
93
4.18 Surface roughness measurement using atomic force microscope (AFM) analysis on diamond coating onWC substrate chemically treated for 3 minutes
95
4.19 Raman Spectrum of the diamond coated WC samples treated with HNO3(65%) + HCl(37%) + H2O solution for 3, 6 and 9 minutes
97
4.20 FESEM images of the flake-off area of diamond coated WC samples treated with HNO3(65%) + HCl(37%) + H2O solution for (a) 3, (b) 6 and (c) 9 minutes
98
4.21 FESEM images and EDX analysis of samples treated with HNO3(65%) + H2O2(30%) solution for (a) 30, (b) 60, and (c) 90 seconds
101
4.22 WC substrate surface roughness etched for 30, 60 and 90 seconds in HNO3(65%) + H2O2(30%) solution
102
4.23 FESEM images of diamond coating on WC samples treated with HNO3(65%) + H2O2(30%) solution for (a) 30, (b) 60 and (c) 90 seconds
103
4.24 XRD spectrums of diamond coating on WC samples treated in HNO3(65%) + H2O2(30%) solution for (a) 30, (b) 60 and (c) 90 seconds
104
4.25 Atomic force microscope (AFM) image of the sample treated with HNO3(65%) + H2O2(30%) for 30 seconds (a) distribution of diamond grain size, (b) average diamond grain size
106
xix
4.26 Atomic force microscope (AFM) 3D images of the diamond coating samples chemically treated for (a) 30, (b) 60 and (c) 90 seconds in HNO3(65%) + H2O2(30%) solution
107
4.27 Surface roughness measurement using atomic force microscope (AFM) analysis on diamond coating onWC substrate chemically treated for 30 seconds
109
4.28 Raman Spectrum of the diamond coated WC samples treated with HNO3(65%) + H2O2(30%) solution for 30, 60 and 90 seconds
110
4.29 FESEM images of the diamond flake-off area of the diamond coatings on WC samples treated with HNO3(65%) + H2O2(30%) solution for (a) 30, (b) 60 and (c) 90 seconds
112
4.30 Difference in adhesion strength in terms of (a) Flake-off diameter (µm) and (b) Flake-off time (seconds). (For X-axis: 1 = H2SO4 + H2O2, 2 = HNO3 + HCl + H2O, 3 = HNO3 + H2O2
116
4.31 FESEM images of diamond coating morphologies on WC substrate seeded with fixed size and concentration of diamond powder and various concentration of SiC powder, (a) 0 g/l, (b) 1 g/l, (c) 5 g/l and (d) 10 g/l
118
4.32 XRD spectrums of diamond coating seeded with diamond and SiC powder concentrations of (a) 0, (b) 1, (c) 5 and (d) 10 g/l
120
4.33 Three dimensional atomic force microscope (AFM) images of diamond coating seeded with diamond and SiC powder concentrations of (a) 0 g/l, (b) 1 g/l, (c) 5 g/l and (d) 10 g/l
122
4.34 Atomic force microscope (AFM) image analysis on diamond grain size and density of diamond coating seeded with 100% of diamond powder
123
4.35 Surface roughness measurement using atomic force microscope (AFM) analysis on diamond coating seeded with 1 g/l SiC powder
125
4.36 Raman spectrum of diamond coatings seeded with diamond and (a) 0 g/l, (b) 1 g/l, (c) 5 g/l and (d) 10 g/l of SiC powder
126
xx
4.37 FESEM images of the diamond flake-off size of the
diamond coatings seeded with diamond and SiC powder with the concentrations of (a) 0 g/l, (b) 1 g/l, (c) 5 g/l and (d) 10 g/l
129
4.38 FESEM images of the diamond coating morphologies after completion of grinding for selected feed rate of, (a) 0, (b) 0.015, (c) 0.045 and (d) 0.075 mm/min
133
4.39 FESEM images and the surface roughness (Ra) values of WC work piece ground with different feed rate, (a) 0, (b) 0.015, (c) 0.030, (d) 0.045, (e) 0.060 and (f) 0.075 mm/min
135
4.40 The trend of the WC work piece surface finish roughness after grinding at different feed rate.
138
4.41 FESEM images of fabricated diamond coated wheel at the grinding edge of in-house fabricated grinding tool. (a) top view and (b) side view at 160O angle
139
4.42 FESEM images of commercial diamond bonded tool at the grinding edge (a) top view and (b) side view at 160O angle
139
4.43 WC work piece mirror surface finish after grinding using (a) in-house fabricated diamond coated and (b) commercial diamond bonded wheels
140
4.44 FESEM images of WC work pieces after grinding with (a) fabricated diamond coated, and (b) commercial diamond bonded wheels
140
4.45 FESEM images of the grinding edge of the fabricated diamond coated tool after grinding using 0.2 mm/min feed rate, (a) top view and (b) side view
141
4.46 FESEM images of the grinding edge of the commercial diamond bonded tool after grinding using 0.2 mm/min feed rate, (a) top view and (b) side view
142
xxi
LIST OF SYMBOLS
A - Ampere
Al2O3 - Aluminium oxide/Alumina
α - Diamond growth factor OC - Degree Celcius
CH3 - Methyl
CH4 - Methane
cm-1 - Per centimeter
cm2 - Centimeter square
cm-2 - Per centimetre square
Co - Cobalt
g/l - gram per liter
H - Atomic hydrogen
H2 - Hydrogen
H2O - Water
H2O2 - Hydrogen peroxide
H2SO4 - Sulphuric acid
HCl - Hydrochloric acid
HNO3 - Nitric acid
hr - hour
K - Kelvin degree
K3[Fe(CN)6} - Potassium ferro-cynide
KOH - Potassium hydroxide
Mbar - Milibar
µm - Micrometer
µmhr-1 - Micrometer per hour
ml/min - milliliter per minute
xxii
mm/min - Milimeter per minute
Mo - Molybdenum
nm - Nanometer
Ra - Average roughness
sccm - Standard cubic centimeters per minute
sec - second
Si - Silicon
SiC - Silicon carbide
Ta - Tantalum
θ - Theta
Torr - Unit pressure
W - Tungsten/Wolfrum
WC - Tungsten Carbide
wt% - Weight percentage
ZrO2 - Zirconia
xxiii
LIST OF ABBREVIATIONS
AFM - Atomic Force Microscope
CTE - Coefficient of Thermal Expansion
CVD - Chemical Vapour Deposition
FESEM - Field Emission Scanning Electron Microscope
HFCVD - Hot Filament Chemical Vapour Deposition
HOPG - High Oriented Graphite Phase
IR - Infrared
PACVD - Plasma Assisted Chemical Vapour Deposition
SEM - Scanning Electron Microscope
UV - Ultraviolet
XRD - X-RAY Diffractometer
xxiv
LIST OF APPENDICES
APPENDIX TITLE PAGE
A List of Publications
155
B AFM Analysis of Diamond Surface Roughness Coated on WC Samples
156
C AFM Analysis of Diamond Grain Density and Size Coated on WC Samples
159
D Raman Spectrums of Diamond Film
167
E Calculations of Diamond Quality and Residual Stress
175
F Tungsten Carbide (WC) Work Piece Surface Finish Profiles Ground at Different Feed Rate
182
G Tungsten Carbide (WC) Work Piece Surface Finish Profiles Ground at Different Feed Rate
184
CHAPTER 1
INTRODUCTION
1.1 Background of the Research
Since the introduction of first coating and coating process, it has been
recognized by the industry that the tool’s performance and its lifetime could be
extended by applying a hard surface to a cutting tool. Further gains in performance
and tool life have been achieved each time advancement in equipment and
technology has made it possible to develop new coatings. Today, there are several
coating processes and numerous types of coatings being used on a wide range of
tools.
One of the main coating materials that held a special interest in the hearts and
minds of the scientists, researchers and engineers is diamond. Diamond which
derived from the Greek word “adamas”, meaning “invincible” is a very impressive
material as it is the hardest known material with the lowest coefficient of thermal
expansion, chemically inert and wear resistance, offers low friction, has high thermal
conductivity, electrically insulating and is optically transparent from the ultraviolet
(UV) to the far infrared (IR) (Asfold et al, 1997). It is formed naturally deep in the
earth under extreme conditions of very high temperature and pressure and the only
known source of diamond for centuries.
With the introduction of high pressure high temperature (HPHT) method in
1950s (May, 1995), the first artificial diamond was crystallized through metal
2
solvated carbon at pressure of about 80 kBar and temperature around 2000OC. For
more than three decades, “industrial diamonds” have been produced commercially by
this method. With the discovery of a various types of chemical vapour deposition
(CVD) techniques in 1960s by Spitsyn et al (1991) in Moscow, has sparked more
interest of scientific nature in this material. It involves the gas phase chemistry
mainly between hydrocarbon and hydrogen gaseous within the vicinity of the surface
which causes diamond deposition onto that surface.
Given all the many positive properties together with the availability of
various CVD techniques, diamond already finds use in many diverse applications as
the optical windows operating in severe environment, heat sinks in electronic
devices, semi conductors applications (field effect transistors, diodes, high voltage-
high current switch, radiation and gas detectors) as well as in mechanical
applications which are commercially available (abrasives, coating on cutting tools
such as inserts, drill bits, end mills, reamers and counter sinks) (Alix Gicquel et al,
2001).
One of the major considerations for the development and production of high
quality diamond coating on cutting tools using CVD techniques is the choice of
appropriate hard material substrates. These hard substrate materials should have
optimal thermal and mechanical properties such as heat conductivity, thermal
expansion coefficient, hardness and toughness as well as having good adaptation to
the CVD coating process. Hard cemented carbide mainly tungsten carbide (WC) that
was normally used as cutting tools was found to be the most suitable material as it
has all the required properties for diamond coating using CVD (Haubner, 1996). The
most widely used of WC for diamond coated cutting tools is WC-6 wt% Cobalt (Co)
which has been manufactured in various complex shapes such as inserts (Arumugam
et al., 2006), (Davim and Mata, 2008), end mills (Gomez et al., 2012), drill bits
(Hanyu et al., 2003), (Chen et al., 2002) and grinding tools (Chou et al., 2010),
(Butler-Smith et al., 2012).
However, the successful diamond coating using CVD technique onto the
WC-6 wt% Co substrate in terms of well faceted crystals, good adhesion, high
quality, uniform coverage and grain size depends on these factors:
3
(a) Co content and the surface roughness of the WC-6wt % Co
(b) Diamond nucleation density
Co binder used in cemented carbide causes the diffusion and dissolution of carbon
during coating process which reduces the diamond nucleation rate and promote the
formation of graphite. This will results in poor coating quality as well as weaker
coating adhesion strength (Jan Gabler and Westermann, 2000; Miao et al., 2004).
During diamond deposition on cemented carbides a surface with only a minimum Co
concentration will allows good diamond deposition (M. Alam, 1997). This is
particularly important for the industrial formation of diamond coatings on cutting
tools. WC substrate surface roughness is essential in promoting high diamond
nucleation density. Amirhaghi (1999) has proved that the scratched area on WC
substrate surface produce high nucleation density as compare to non-scratched area
and this factor promote high adhesion strength, uniform coverage and grain size.
Various methods and techniques have been successfully employed to prepare
the WC substrate surface prior to diamnd coating such as introduction of Co inter-
diffusion barrier interlayer (Amirhaghi et al., 1999; Chou et al., 2008), biasing
(Chiang and Hon, 2008; (Saito et al., 2009) as well as chemical pretreatment (Saito
et al., 2009; Raghuveer et al., 2002). Two-step chemical pretreatment (Sien et al.,
2004; Volker Buck et al., 2002) followed with diamond seeding (Xu et al., 2013;
Wei et al., 2011) is however, simple, effective and widely used to roughen,
minimized surface Co concentration as well as creating better diamond nucleation
sites.
1.2 Problem Statement
Successful diamond coating on cemented WC requires solutions to the
problems of adequate diamond nucleation and most importantly poor adhesion. The
poor adhesion between diamond coating and the WC substrate results from the
thermal expansion mismatch between the diamond coating and the substrate, which
4
lead to large thermal stresses at the interface, and the presence of binder materials
such as Co in the substrate, will enhance the graphite formation. Currently the most
effective, simple and cheap technique employed by most researchers to improve the
adhesion strength and nucleation density of diamond on WC substrate is through the
combination of two-step chemical pretreatment and diamond seeding process
(Almeida et al, 2011). The adhesion strength is further improved by mixing other
small particles such as Ti (Bujinster et al., 2009) and SiC (Avigal and Hoffmann,
1999) with diamond powder during seeding. However, this technique mostly applied
to produce not only high adhesion strength but also high diamond nucleation density
which means small and uniform grain size. This condition is only suitable for cutting
tools (inserts, end-mill and drill bits) in order to maintain the cutting point or cutting
edge of the tools as well as to provide wear resistant properties. However, for
abrasive application mainly for grinding, the rough surface finish of diamond film is
necessary where the entire diamond grains will act as cutting points for minute
material removal. At the same time it also provides clearance between the grains to
accommodate the grinding chips (Kopac and Krajnik, 2006). The smooth surface of
diamond film with very fine, uniform and high density of diamond grains is however
not suitable for grinding application as there will no cutting action take place.
Currently, most of the CVD diamond coated grinding wheels have been produced by
machining of solid CVD diamond pieces (Butler-Smith et al., 2012) or by laser
patterning the diamond grains (Butler-Smith et al, 2009) which is very costly
processes. The application of chemical pretreatment and seeding which is a viable
process and cheaper on WC grinding tools was however minimally reported. A
thought of applying smaller diamond powder size mix with larger size of second type
of powder on WC grinding wheel substrate surface during seeding that may produce
rough surface finish with larger grains of diamond coating and its grinding
performance which is unknown is worth to be investigated.
1.3 Objectives of the Research
The main objective of this research is to establish the hot filament chemical
vapour deposition (HFCVD) diamond coating film with high adhesion strength and
5
quality with appropriate grain size and distribution suitable for grinding application.
The specific objectives for this research are as follows:
1. To determine suitable chemical pretreatment process and seeding
parameters that can produce high quality of diamond coating for
grinding application..
2. To evaluate and compare the grinding performance in terms of the
condition of the wheels and the surface finish of the work piece
between fabricated diamond coated WC and the commercial diamond
bonded WC wheels.
1.4 Scopes of the Research
The research scopes are as follows:
1. The cemented tungsten carbide (WC-6 wt% Co) was selected as a
substrate material.
2. Two-step pretreatment was chosen as the method to prepare the WC
substrate surface with the first step was fixed using Murakami solution
for 20 minutes. For second step of treatment, three different chemicals
were used with three different etching times.
3. Seeding process was conducted using fixed size and concentration of
diamond powder mixed with fixed size (174 μm) and different
concentrations (0, 1, 5 and 10 g/l) of SiC powders
4. Diamond coating was conducted using hot filament CVD (HFCVD)
with fixed parameters for 30 hours.
5. Surface characterizations on the chemically treated substrates were
analyzed by using FESEM, EDX and surface roughness tester for
element, morphology and surface roughness respectively.
6
6. Surface characterization on the diamond coated substrates were
analyzed under FESEM, XRD, Raman Spectrometer, AFM for
morphology, quality and surface roughness
7. The adhesion strength of diamond films was determined through the
size of diamond flake-off area and time to flake-off using blasting
technique.
8. Grinding was performed on WC-2 wt% Co work piece using ultra-
precision cutting and grinding machine with varying feed rate as other
parameters are fixed.
9. Analysis of grinding was conducted on the grinding wheels in terms
of grinding edge conditions as well as on the WC samples in terms of
finishing surface morphology and roughness using FESEM and
surface profiler respectively.
1.5 Significance of the Research
This research is expected to provide an alternative method to produce suitable
CVD polycrystalline diamond on WC substrate for abrasive application which
should be comparable with diamond bonded wheels. With the application of simple
and cheap conventional two-step pretreatment process combine with mix seeding to
provide proper substrate conditions, should open up further research in producing
different grain sizes of diamond coating for different grinding applications.
CHAPTER 5
CONCLUSIONS AND RECOMMENDATIONS FOR FUTURE WORK
5.1 Conclusions
Various methods have been employed to increase the adhesion
strength of CVD diamond film on to the WC substrate. Two-step
pretreatment followed with diamond powder seeding are found to be very
effective in increasing the diamond nucleation density with the purpose of
increasing the adhesion strength adhesion strength. Seeding using mixture of
diamond powder with large size of second material powders has been proved
more effective in increasing the diamond nucleation density. However, most
of the reports published used Si as a substrate. Employing even larger powder
size of second material during seeding with the intention of producing larger
diamond grain size and at the same time having high adhesion strength was
still not reported. This experimental study was conducted to determine the
effect using large second material powder size on the adhesion strength of
diamond film and the diamond grain size. The grinding tests were conducted
to determine the effectiveness of the produced diamond grains. This
experimental study is concluded with following findings:
1. Application of large SiC powder with small diamond powder size
during seeding has produced large HFCVD diamond grains with the
same structure consist of mixture of (111) and (220) structures
144
regardless of the different second step pre-treatment. It is suspected
due to the same seeding condition conducted on all the samples.
However, the adhesion strength were varied, due to various factors
and such as high surface Co content, high residual stress as well as
lower density of diamond grains. Sample treated with HNO3 +
H2O2 for 60 seconds has the highest adhesion strength due to lowest
surface Co and highest grain concentration. This indicates that the
concentration of substrate surface Co and the diamond nucleation
density are the major factors in determine the adhesion strength.
2. The adhesion strength of the diamond film was also found to be
depend on the amount of large second material powders used during
the seeding. With the same pretreatment conducted on the samples, it
is clearly indicates that with a certain ratio of mix seeding, will
produce a certain adhesion strength. In this particular experiment,
sample seeded with diamond and 1 g/l has the highest adhesion
strength due to highest diamond grain concentration and diamond
quality. This selected seeding condition also produced almost uniform
height and distribution of diamond grain and on top of that sharp peak
of the grains which is suitable for grinding application. The diamond
grain concentration was lower as compare to sample seeded with only
diamond powder. This is expected as with only diamond powder used,
there was no restriction of the powders to be embedded into the WC
substrate surface. The adhesion strength of sample seeded with only
diamond, however was lower due to no hammering effect of large SiC
powder onto the diamond powder during seeding.
3. The mirror image surface finish with the minimum roughness, Ra of
0.007 µm of the WC work piece was achieved with no indication of
any defect occur to the diamond coated grinding wheel. When
grinding performance was compared with diamond bonded wheel, the
surface finish of the work piece was at par. However, the problem of
grinding chips clogging is obvious which commonly found in
147
Bachmann, P. K., Leers, D. and Lydtin, H. (1991). Towards a general concept of
diamond chemical vapour deposition. Diamond and Related Materials. 1(1):
1-12
Bichler, R., R. H. and Lux, B. (1989). Influence of the cobalt content in hot-pressed
cemented carbides on the deposition of low-pressure diamond layers. Journal
de Physique. C5(5): 169-176
Brown, W.D., Beera, R.A., Naseem, H.A. and Malshe, A.P. (1996). State-of-the-art
synthesis and post-deposition processing of large area CVD diamond
substrates for thermal management. Surface and Coatings Technology. 86-87:
698-707
Buck, V., F. D., Kluwe, H. and Schmiler, B. (2002). Influence of chemical
pretreatment of hardmetal substrates for diamond deposition. International
Journal of Refractory Metals & Hard Materials. 20(2): 101-105.
Bujinsters, J. G., Vazquez, L. and ver Meulen, J. J. (2009). Substrate pre-treatment
by ultrasonication with diamond powder mixtures for nucleation
enhancement in diamond film growth, Diamond and Related Materials.
18(10): 1239-1246
Butler-Smith, P.W., Axinte, D.A. and Daine, M. (2012). Solid diamond micro-
grinding tools: From innovative design and fabrication to preliminary
performance evaluation in Ti–6Al–4V. International Journal of Machine
Tools and Manufacture. 59: 55-64.
Butler-Smith, P.W., Axinte, D.A. and Daine, M. (2009). Preferentially oriented
diamond micro-arrays: A laser patterning technique and preliminary
evaluation of their cutting forces and wear characteristics, International
Journal of Machine Tools & Manufacture. 49: 1175–1184
Cabral, G., J. C. M., Titus, E., Ali, N. and Grácio, J. (2006). Diamond chemical
vapour deposition on seeded cemented tungsten carbide substrate. Thin Solid
Films. 515: 158-163.
Chakk, Y., Brener, R. and Hoffman A. (1996). Mechanism of diamond formation on
substrate abraded with a mixture of diamond and metal powders. Diamond
and Related Materials. 5: 286-291
Chen, M. X. G. G., Sun, F.H., Hu, B., Liu, X.S. (2002). Development of diamond
coated drills and their performance. Journal of Materials Processing
Technology. 129: 81-85.
148
Chiang, M. J. and Hon, M. H. (2008). Microstructure investigation of
positive/negative direct current bias-enhanced diamond deposition. Thin Solid
Films. 516: 5953-5958.
Chou, C.C., Lee, J.W. and Chen, Y.I. (2008). Tribological and mechanical properties
of HFCVD diamond-coated WC-Co substrates with different Cr interlayers,
Surface & Coatings Technology. 203: 704–708
Chou, Y.K., Thompson, R.G. and Kumar, A. (2010). CVD-diamond technologies for
dry drilling applications. Thin Solid Films. 518: 7487-7491.
Cristofanilli, G., Polini, R. and Barletta, M. (2010). HF-CVD of diamond coatings
onto Fluidized Bed (FB) treated CrN interlayers. Thin Solid Films. 519: 1594-
1599.
Davim, J. P. and Mata, F. (2008). Chemical vapour deposition (CVD) diamond
coated tools performance in machining of PEEK composites. Materials &
Design. 29: 1568-1574.
Davis, J.R. (2000). ASM Specialty Handbook: Nickel, Cobalt and Their Alloys (1st
Ed.), Materials Park, OH : ASM International
Deuerler, F., H. v. d. B., Tabersky, R., Freundlieb, A., Pies, M. and Buck, V. (1996).
Pretreatment of substrate surface for improved adhesion of diamond films on
hard metal cutting tools. Diamond and Related Materials. 5(12): 1478-1489.
Gäbler, J., Schäfer, L., Menze, B., and Hoffmeister, H.W. (2003). Micro abrasive
pencils with CVD diamond coating. Diamond and Related Materials. 12,
707-710.
Geng, C.L., Tang, W.Z., Hei, L.F., Liu, S.T. and Lu, F.X. (2007). Fracture strength
of two-step pretreated and diamond coated cemented carbide microdrills.
International Journal of Refractory Metals & Hard Materials. 25: 159-165
Gicquel, A.K.H., Silva, F. and Achard J. (2001). CVD diamond films: from growth
to applications. Current Applied Physics. 1: 479-496
Gomez, H., Durham, D., Xiao, X., Lukitsch, M., Lu, P., Chou, K., Sachdev, A. and
Kumar, A. (2012). Adhesion analysis and dry machining performance of
CVD diamond coatings deposited on surface modified WC–Co turning
inserts. Journal of Materials Processing Technology. 212: 523-533.
149
Hanyu, H., Murakami, Y., Kamiya, S., and Saka, M. (2003). New diamond coating
with finely crystallized smooth surface for the tools to achieve fine surface
finish of non-ferrous metals. Surface and Coatings Technology. 169-170:
258-261.
Haubner, R. B. L. (1996). On the Formation of Diamond Coatings on WC/Co Hard
Metal Tools. Int J of Refractory Metals & Hard Materials. 14: 111-118
Hayashi, Y., Drawl, W. and Messier, R. (1992). Temperature dependence of
nucleation density of chemical vapour deposition diamond. Japan Journal of
Applied Physics. 31(2B): 193-196
Herlinger, J. (2006). sp3's experience using hot filament CVD reactors to grow
diamond for an expanding set of applications. Thin Solid Films. 501(1-2): 65-
69
Huang, T.H., C. T. K., Chang, C.S., Kao, C.T. and Wen. H.Y. (1992). Tribological
behaviours of the diamond-coated cemented carbide tools with various cobalt
contents. Diamond and Related Materials. 1(5-6): 594-599.
Huimin Liu and Dandy, S. D. (1995). Studies on nucleation process in diamond
CVD: an overview of recent developments. Diamond and Related Materials.
4(10): 1173-1188
Jan Gabler, L. S., Westermann, H. (2000). Chemical vapour deposition diamond
coated microtools for grinding, milling and drilling. Diamond and Related
Materials. 9: 921-924.
Jan Gabler, Sven Pleger. (2010). Precision and micro CVD diamond-coated grinding
tools. International Journal of Machine Tools & Manufacture. 50: 420–424
Jeon, In-D., Park, C.J. Park, Kim, D.Y. and Hwang N.M. (2001). Effect of methane
concentration on size of charged clusters in the hot filament diamond CVD
process. Journal of Crystal Growth. 223: 6-14
Kamiya, S., Yoshida, N., Tamura, Y., Saka, M., and Abé, H. (2001). Quantitative
measurement for the effect of enhanced nucleation on the adhesive strength
of diamond coatings. Surface and Coatings Technology. 142–144: 738-742.
Kang, J., Xiao, C., Xiong, Y., Wang, Y., Meng, Q., Lin, Z. and Feng, Ke-an (2000).
Diamond nucleation and growth under very low-pressure conditions.
Diamond and Related Materials. 9: 1691-1695
Kopac, J. and Krajnik, P. (2006). High performance grinding-A review, Journal of
Materials Processing Technology. 175: 278-284
150
Lu, F.X., W. Z. T., Y.M. Tong, Y.M., Miao, J.Q., He, L.F., Li, C.M. and Chen, G.C.
(2006). Novel pretreatment of hardmetal substrate for better performance of
diamond coated cutting tools. Diamond and Related Materials. 15(11-12):
2039-2046
Malcher, V., Mrska, A., Kromka, A., Šatka, A. and Janı́k, J. (2002). Diamond film
coated on WC/Co tools by double bias-assisted hot filament CVD. Current
Applied Physics. 2(3): 201-204.
Mallika, K. and Komanduri R. (1999). Diamond coatings on cemented tungsten
carbide tools by low-pressure microwave CVD. Wear. 224: 225-266
May P. W. (1995) CVD Diamond : A New Technology For The Future? Endeavour,
Elsevier, Oxford. 19(3): 101-106
May P. W. (2000). Diamond thin films: a 21st-century material. Phil. Trans. R. Soc.
Lond. A. 358: 473–495
Menon, P. M., Clausing, R. E., Heatherly, L. and Feigerle, C.S. (1998). The
morphology of diamond grown by hot filament chemical vapor deposition.
Diamond and Related Materials. 8(1): 101-109
Miao, J., Song, J., Xue, Y., Tong, Y., Tang, W., and Lu, F. (2004). Effect of a two-
step pretreatment method on adhesion of CVD diamond coatings on
cemented carbide substrates. Surface and Coatings Technology. 187, 33-36
Moore, M. (2001). Diamond : Natural. Buschow, K.H.J. Encyclopedia of Materials:
Science and Technology. New York : Elsevier, 2133-2143
Nicholson, E.D., Weeks, J.R. and Ashfold, M.N.R. (1997). The effect of varying
deposition conditions on the Young’s modulus of diamond coated wires.
Diamond and Related Materials. 6: 817-821
Park, B.S., Baik, Y.J., Lee, K.R., Eun, K.Y. and Kim, D.H. (1993). Behaviour of Co
binder phase during diamond deposition on WC-Co. Diamond and Related
Materials. 2(5-7): 910-917
Park, S.S. and Lee, J.Y. (1993). Nucleation behaviour of diamond particles on silicon
substrates in a hot filament chemical vapour deposition. Journal of Materials
Science. 28: 1799-1804
Paulmier, D, T. L. H. and Zaidi, H. (1997). Growth and orientation of diamond
crystals thin films obtained by the combustion-flame method. Surface
Science. 5: 377-379.
151
Pierson, H.O. (1999). The CVD of the Allotropes of Carbon. Andrew, W., Handbook
of Chemical Vapour Deposition. New Jersey : Noyes Publications, 185-216
Polini, R. (2006). Chemically vapour deposited diamond coatings on cemeted
tungsten carbides: Substrate pretreatments, adhesion and cutting performance.
Thin Solid Films. 515: 4-13.
Polini, R. and Barletta, M. (2008). On the use of CrN/Cr and CrN interlayers in hot
filament chemical vapour deposition (HF-CVD) of diamond films onto WC-
Co substrates. Diamond & Related Materials. 17: 325–335
Polini, R. and Tomellini, N. (1995). Analysis of size distribution functions of
diamond crystallites form in early stages of chemical vapour deposition.
Diamond and Related Materials. 4(12): 1311-1316
Polini, R., Bravi. F., Casadei, F., D'Antonio, P. and Traversa, E. (2002). Effect of
substrate grain size and surface treatments on the cutting properties of
diamond coated Co-cemented carbide tools. Diamond and Related Materials.
11(3-6): 726-730
Poporici, G. and Prelas, M.A. (1992). Nucleation and selective deposition of
diamond thin films. Physica Status Solidi A. 132(2): 233-252
Poulon-Quintin, A., Faure, C., Teulé-Gay, L., and Manaud, J.-P. (2010). Bilayer
systems of tantalum or zirconium nitrides and molybdenum for optimized
diamond deposition. Thin Solid Films. 519: 1600-1605.
Priyadarshini K., S. R. S., S.T. Kshirsagar. (1998). Role of surface features in CVD
diamond nucleation on surface-pretreated substrate. Materials Letters. 34(3-
6:, 387-391
Raghuveer, M. S., Yoganand, S. N., Jagannadham, K., R.L. Lemaster, R. L. and
Bailey, J. (2002). Improved CVD diamond coatings on WC–Co tool
substrates. Wear. 253: 1194–1206
Sahoo, B. and Chattopadhyay, A.K. (2002). On effectiveness of various surface
treatments on adhesion of HF-CVD diamond coating to tungsten carbide
inserts. Diamond and Related Materials. 11(9): 1660-1669.
Saito, D., Isshiki, H. and Kimura, T. (2009). Positive-bias enhanced growth of high
quality diamond films by microwave plasma chemical vapor deposition.
Diamond and Related Materials. 18: 56-60.
152
Sarangi, S.K. and Chattopadhyay, A.K. (2008). Effect of pretreatment methods and
chamber pressure on morphology, quality and adhesion of HFCVD diamond
coating on cemented carbide inserts. Applied Surface Science. 254: 3721-
3733.
Schäfer, L., Höfer, M. and Kröger, R. (2006). The versatility of hot-filament
activated chemical vapor deposition. Thin Solid Films. 515: 1017-1024.
Schwarz, S., Rosiwal, S.M., Frank, M., Breidt, D. and Singer, R.F. (2002).
Dependence of growth rate, quality and morphology of diamond coatings on
the pressure during the CVD process in an industrial hot-filament plant.
Diamond and Related Materials. 11(3-6): 589-595.
Sein, H., Ahmed, W., Jackson, M., Polini, R., Hassan, I., Amar, M. and Rego, C.
(2004). Enhancing nucleation density and adhesion of polycrystalline
diamond films deposited by HFCVD using surface treaments on Co cemented
tungsten carbide. Diamond and Related Materials. 13: 610–615
Shen, B. and Sun, F. (2009). Deposition and friction properties of ultra-smooth
composite diamond films on Co-cemented tungsten carbide substrates.
Diamond and Related Materials. 18: 238-243.
Silva, F., Gicquel, A., Tardieu, A., Cledat, P. and Chauveau, T. (1996). Control of an
MPACVD reactor for polycrystalline textured diamond films synthesis: role
of microwave power density. Diamond and Related Materials. 5: 338-344
Soderberg, S., Westergren, K., Reineck, I., Ekholm, P-E. and Shahani, H. (1991).
Properties and performance of diamond coated ceramic cutting tools.
Materials Science Monograpahs. 73: 43-51
Spitsyn, B. V., Bruilov, L.L. and Deryagin, B.V. (1991). Vapor Growth of Diamond
and Other Surfaces. Journal of Crystal Growth. 52: 219-226
Stankovic, S., Rakocevic, Z. and Marinkovic, S. (1999). Effect of the pretreatment of
a cemented carbide surface on its properties and on the properties of diamond
coatings deposited by oxygen-acetylene flame CVD. Diamond and Related
Materials. 8(2-5): 207-210.
Stoner, B.R., Williams, B.E., Walter, S.D., Nishimura, K. and Glass J.T. (1992). In-
situ growth rate measurement and nucleation enhancement for microwave
plasma CVD of diamond. J. Mater. Res. 7(2): 257-260
153
Taher, M.A., Schmidt, W.F., Brown, W.D., Nasrazadani, S., Nasseem, H.A. and
Malshe, A.P. (1996). Effect of methane concentration on mechanical
properties of HFCVD diamond-coated cemented carbide tool inserts. Surface
and Coatings Technology. 86-87: 678-685
Taher, M.A., Schmidt, W.F., Brown, W.D., Nasseem, H.A. and Malshe, A.P. (1998).
Effect of methane concentration on physical properties of diamond-coated
cemented carbide tool inserts obtained by hot-filament chemical vapour
deposition. Journal of Materials Science. 33: 173-182
Tang, C.J., Neves, A.J. and Fernandes A.J.S. (2003). Influence of nucleation density
on film quality, growth rate and morphology of thick CVD diamond films.
Diamond and Related Materials. 12: 1488-1494
Tang, Y., Li, Y. S., Yang, Q. and Hirose, A. (2010). Deposition and characterization
of diamond coatings on WC-Co cutting tools with W/Al interlayer. Diamond
and Related Materials. 19: 496-499
Uhlmann, E. and Koenig, J. (2009). CVD diamond coatings on geometrically
complex cutting tools. CIRP Annals - Manufacturing Technology. 58: 65-68
Vojs, M., Vesely, M., Redhammer, R., Janík, J., Kadlečíková, M., Daniš, T., Marton,
M., Michalka, M. and Šutta, P. (2005). Double bias HFCVD multilayer
diamond films on on WC-Co cutting tools. Diamond and Related Materials.
14(3-7): 613-616
Wang, S.G., Qing Zhang, Yoon, S.F., Ahn, J., Wang, Q., Yang, D.J., Huang, Q.F.,
Rusli, Tang W.Z. and Lu, F.X. (2002). CVD diamond nucleation enhanced
by ultrasonic pretreatment using diamond and mixture of diamond and TaC
powders. Diamond and Related Materials. 11: 1683-1689
Webster, J. and Tricard, M. (2004). Innovations in Abrasive Products for Precision
Grinding. CIRP Annals-Manufacturing Technology. 2(53): 597-617
Wei, Q. P., Ashfold, M. N. R.,Yu, A., Mankelevich, Z.M., Yu, P.Z. and Liu, L. Ma
(2011). Diamond growth on WC-Co substrates by hot filament chemical
vapor deposition : Effect of filament–substrate separation. Diamond and
Related Material., 20: 641–650
Wei, Q. P., Z. M. Y., Ashfold, M. N. R., Ye, J. and L. Ma, L. (2010). Synthesis of
micro- or nano-crystalline diamond films on WC-Co substrates with various
pretreatments by hot filament chemical vapor deposition. Applied Surface
Science. 256(5): 1322-1328.
154
Xu, F., Xu, J. H., Yuen, M. F., Zheng, L., Lu, W. Z. and Zuo, D. W. (2013).
Adhesion improvement of diamond coatings on cemented carbide with high
cobalt content using PVD interlayer, Diamond and Related Materials. 34:
70–75
Yarbrough, W. A. and Messier, R. (1990). Current issues and problems in chemical
vapour deposition of diamond. Science. 247: 688-696
Zhang, G.F. and Buck, V. (2002). Lower filament temperature limit of diamond
growth in a hot-filament CVD system. Surface and Coatings Technology.
160: 14-19