Nanodiamond structure and properties. 3. 2. ... aggregated and the aggregates form micro-sized agglomerates. ... Electron mobility at room T: 2200 cm²/V sec, hole mobility: 1600 cm2V-1s-1 ... ND isolation from detonation blend & following ... Yield, wt. % of the explosives weight. Conditions of Synthesis. In gas medium.
Training carried out by Ray Techniques Ltd. in 2016-2017
WP 2:
Fabrication of Nano-Carbons
Task 1.3
Training on nanodiamond synthesis
Task leader:
Boris Zousman
Edited by:
Olga Levinson
2
1. Nanodiamond structure and properties
3
2. Methods of nanodiamond fabrication
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1) Detonation synthesis
12
2) High-Pressure High-Temperature technology
17
3) CVD diamond synthesis
25
4) Other methods of ND synthesis
34
5) ND fabrication by milling
35
6) Light Hydro-Dynamic Pulse technology
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3. Nanodiamond characterization
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4. Nanodiamonds for biomed
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3
Nanodiamond Structure
1
▪ Nanodiamond (ND) has cubic diamond lattice and relates to the family of carbon nanostructures with a size of < 100 nm. ▪ ND particles, like other nanostructures, are usually strongly aggregated and the aggregates form micro-sized agglomerates.
▪ Unique properties of ND are caused by: a)
their crystalline structure (the lattice of carbon atoms and their electron orbitals, which are different in diverse carbon materials);
b)
additional features related to nano-dimensional structure of ND, relatively high ratio of surface atoms in the crystallite having un-paired electrons and bonded with chemically active functional groups.
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a) b) c) d) e) f) g)
Diamond Graphene Lonsdaleite C60 fullerene C540 fullerite C70 fullerene Amorphous carbon h) CNT and other nanostructures
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Nucleus:
Carbon atom
Formation of 4 hybrid electron orbitals sp3 in C
Neighbor C atoms share 2 electrons & form 4 covalent bonds in diamond
sp3 electronic configuration
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1.
Electrons, moving along 4 sp3 hybridized orbitals with angles between them of 109°47’ and maximum electronic overlap to each other, form crystal lattice, in which each atom is covalently bonded to 4 neighbor atoms, which are located at the same distance of 154 pm.
2.
The elementary cell of the diamond structure consists of 14 symmetrically arranged tetrahedral bonded carbon atoms forming a triangular prism.
3.
The prisms are bonded covalently in the very rigid threedimensional cubic lattice of the densely packed C atoms, which determines unique properties of the diamond.
4.
The I, II, III, IV & V nearest-neighbor distances in units of the cubic lattice constant are atomic√3/4, √2/2, √11/4, 1 and √19/4, respectively. The highest atomic density 1.76х1023 сm-3
1.
0,357 nm
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▪ Extreme mechanical hardness 98 GPa {111}; bulk modulus 1.2x10¹² N/m² ▪ Outstanding optical & electronic properties •
Electron mobility at room T: 2200 cm²/V sec, hole mobility: 1600 cm2V-1s-1
•
Refractive index: 2.419; Wide band gap {300 K}: 5.47 eV
▪ Thermal conductivity: 2000 W/mK, heat capacity: 6.2 Jmol-1K-1
▪ Electrical resistivity: 1013-1015 ῼcm, dielectric constant: 5.7 ▪ Sound propagation velocity along : 18.4 ▪ Chemical & radiation resistance
(energy for replacement atom from lattice ≈43 eV) ▪ Biological compatibility and non-cytotoxity
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• Diamond core (sp3) with the size of less than 100 nm having unique properties of diamond
• Hybrid surface structure (sp2) with unpaired electrons • Various surface functional groups containing O, H and N
ND features: tiny size, stable nucleus and chemically active shell; large surface area and high adsorption potential, Surface chemistry can be controlled, which enables to attach diamond crystallites to bio-molecules and design diverse bio-objects with desired unique properties.
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▪ Wide range of surface functional groups define the variety of ND reactivity ▪ Controlling the surface chemistry and narrow size distribution provides the repeatability of ND behavior in diverse interactions with other materials and objects.
▪ Surface modification is required for producing stable ND suspensions. ▪ Carboxyl & hydroxyl groups on ND surface are responsible for dispersibility & stability of ND water suspensions.
Image from www.neomond.com
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2
Methods of ND Synthesis 1.
Detonation of Explosives
2.
High-Pressure-High-Temperature (HPHT)
3.
Chemical Vapor Deposition (CVD)
4.
Other methods of ND Synthesis (not economical)
5.
1)
Ultrasonic Cavitation (UC)
2)
Hydrothermal Synthesis (HTS)
3)
Ion Bombardment (IB)
4)
Pulse Laser Ablation (PLA)
Light Hydro-Dynamic Pulse (LHDP)
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The stable bonding configuration of C at ambient conditions is graphite, with an energy difference between the graphite and the diamond of 0.02 eV per atom. Due to the high energetic barrier between the two phases of C, the transition from diamond to the stablest phase of graphite at normal conditions is very slow.
Image from F.P. Bundy, J. Geophys. Res. 85, B12, 6930 (1980).
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1. Detonation of explosives mixture (TNT & RDX) in closed metal reactors
Advantages:
Commercially 2. ND isolation from detonation blend & following purification by boiling in HNO3, washing & drying available & relatively low cost
Disadvantages:
Tehran Lesnoy
Zhitomir
St. Petersburg
Polluting hazardous & non-controllable process ND of insufficient purity & uniformity, difficult for use and expensive
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Images by Dr. Valeriy Dolmatov, ZAO Almazny Tsentr (Diamond Center, Russia)
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Image by Dr. Valeriy Dolmatov, (Diamond Center, Russia)
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Different conditions of ND detonation synthesis: 1.
in air, or in an atmosphere of a previous explosion or in an inert gas
2.
in an aqueous media in detonation chamber
3.
in the ice shield of the charge.
Products: Detonation Soot (DS) and Detonation ND powder (DND) Productivity of ND detonation Synthesis Yield, wt. % of the explosives weight
Conditions of Synthesis In gas medium
In water
In the ice shield
3-8
6-12
8-14
ND amount in soot
20-40
40-63
55-75
ND yield to explosives
0.6-3.2
2.4-7.6
4.4-10.5
Detonation Soot
Data presented by V. Yu. Dolmatov
Drawbacks: non-constancy of properties & non-readiness for further use.
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Several hypothesizes of ND formation at detonation synthesis have been suggested, particularly, chemical mechanism proposed by Dr. V Dolmatov. Molecule of TNT
Molecule of RDX
Dimer C2
Cyclohexane
Explosive decomposition at the front of a shock wave Adamantane
The possible decomposition of the explosive molecules in the chemical reaction zone. The DND is formed from ~ 95 wt.% of TNT carbon and ~ 5 wt.% of RDX carbon.
Growth of DND particle in all directions
Diamond
V. Dolmatov et al, J. of Superhard Mat.,2013, 35-3
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▪ HPHT is the most common method for fabrication synthetic diamonds. ▪ The process involves large presses weighing hundreds of tons.
▪ A diamond growth cell contains a tiny diamond seed, pure graphite and a metal catalyst. ▪ The cell is placed between the anvils of a powerful hydraulic press and heated to over 1,300 °C. at the pressure of over 3.5 GPa. ▪ As the T and P increase, the catalyst turns into a molten metal solution. Then the graphite dissolves into this solution. Through a controlled cooling process, the C atoms are slowly collected in crystal structure of the diamond seed.
Scheme of a belt press for HPHT diamond synthesis
The Global Leaders: AOTC, Lucent, CGL, Iia Technologies (formerly Gemesis), Chatham, New Diamond Technology
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1941: start of research 1954: 1st commercial diamond synthesis: T=2,000 °C; P=10 GPa using hydraulic press with WC anvils & pyrophyllite container for graphite sample dissolved in metal catalysts molten Ni, Co, Fe.
Scheme of a tapered piston 'belt' apparatus designed at GE
Left: diamond growing region Above: photomicrographs of synthesized diamonds H. P. Bovenkerk et al; Preparation of diamond; Nature, Vol.184, 1959.
In parallel, ASEA (Sweden electrical Co’) achieved the first diamond synthesis in 1953 at HP of 8.4 GPa.
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1
1.
Belt: vertical anvils supply HP to a cylindrical inner cell. HP is confined by a belt of steel bands or hydraulic P. The anvils provide also electric current to heat the cell.
2.
Cubic: 6 anvils provide pressure onto all faces 2 2 of a cube-shaped cell, rapidly achieving operating HP & HT.
3.
Split-sphere (BARS): a chamber is filled with oil, locked & pressed by 8 anvils; the heated oil, presses the cell placed into a cubic-shaped pressure-transmitting material and heated up 3 by a coaxial graphite heater.
4.
Toroid: the die surfaces have circular grooves filled with a solid medium providing uniform distribution of HT & HP in the cell.
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1) 2) 3) 4) 5)
Anvil Gasket Graphite Heater Catalyst
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Dr. Hall invented the “Belt” press in 1953 working in GE.
30 ton KOBELCO belt press produced in 1980.
700 ton KAMATA belt press used in CGL (Japan)
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A cubic press is typically smaller than a belt press, rapidly achieving required HP & HT. ▪ 6 electrically-insulated anvils provide HP New Diamond Technology on all faces production factory in St. Petersburg (Russia): over 30 of cubic cell cubic presses. Manufacturing of HPHT cubic hydraulic presses in China
▪ The cell is composed of diamond powder & tungsten carbide substrate. ▪ The problem: non-uniform heating resulting in a faulty sintering process (Bhaumik et al,1996).
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▪
BARS is Russian abbreviation of pressfree high-pressure setup "split sphere“ invented in 1989 in USSR.
▪
The diameter is ~1 m. The cell is of about 2 cm3 in size.
▪
Typical HP & HT achievable with BARS are 10 GPa and 2500°C.
Two BARS devices, closed one & opened for loading or unloading one
Scheme of BARS press, image from Wiki
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Image by D. Choudhary & J. Bellare
Images by Prof. N. Novikov
Toroid apparatuses in Bakul Institute for Super-hard Materials, Kyiv, Ukraine •
Cells of 4 - 300 cm3 at pressure 8 -2 GPa,
•
Cells of 0.1- 0.3 mm3 at pressure up to 100 GPa
The transformation temperatures at these pressures are 1,500–3,000 K respectively.
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▪ CVD diamond synthesis: sp3 hybridization of C atoms of thermally destructed methane with surface atoms of D crystals in the presence of H at T of 700 1000 °C and reduced P. ▪ Firstly CVD D synthesis was reported by Angus, Will & Stanko in 1968: ▪ Hypothesis: since the transition D=>G doesn’t occur at T1000°C, a D seed crystal has to grow in a C super-saturated environment at T of 10001300°C; G growth is not expected, though sp2 bonding on D surface cannot be avoided.
Flow system for the deposition of diamond
▪ Experiment: thermal decomposition of methane gas at P of 0.15 - 458 Torr and at T of 12530 -1338 °K. Then G was removed by reaction with H gas at 1033°C and 50 atm. ▪ D synthesis was confirmed by testing, D weight increased by 10 %). E. Angus et al, J. of App Physics; June 1968
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▪ Methane & hydrogen (H) mixture (usually 1 & 99 vol. % respectively) pass activation area in a chamber. ▪ Obtained CHx radicals & atomic H impact the surface of a diamond (D) seed and cause its growth. ▪ D film is obtained under low P of 20–100 Torr at T of 600– 1000 °C. ▪ D films are typically grown on D or Si (with D precursors) Image from website substrates.
of University of Bristol
▪ Structure of D films depends on the grain size & uniformity of seeding. D gems are used for monocrystalline D growth, and ND are used as precursors for polycrystalline films.
▪ Various dopants can be incorporated into D lattice during CVD synthesis. Additional gases can be used. Image by O. Williams et al, Diamond & Related Materials 17 (2008) 1080–1088
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2 types of D growth:
▪ Homoepitaxial growth: using D substrates => D lattice is extended atom-by atom during CVD process, resulted in the growth of monocrystalline D. ▪ Heterojunction growth: using non-D substrate => pre-treatment to introduce D precursors within substrate surface: ▪ by abrasion of the substrate surface with diamond powder ranging in size from 10 nm to 10 um (lapping / polishing); ▪ by ultrasonic treatment of the substrate in wateror IPA-based diamond slurry (usually highly dispersed DND particles), resulted in the growth of polycrystalline D films. Image by Prof. J. C. Angus, Case
At the I stage D growth continues in three dimensionsWestern Reserve University
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▪ Atomic H reacts with H of C-H functional group on D surface forming H2 & leaving a reactive C atom. ▪ CH3 replace H & form C-CH3 bonds.
▪ Then atomic H reacts with C-CH3 forming H2. Scheme of CVD process. D.Goodwin & J. Butler, in Handbook ed. by M.A. Prelas et al, 1997.
C in Standard growth model. ▪ Activated neighbor radicals Harris,1990, May, 2000. From Bristol Un. website form covalent bond
Reactive hydrocarbon radicals & atomic H are created in the activation area. Addition of C atoms from radicals to existing D lattice occurs under the impact of atomic H.
joining D lattice.
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D growth strongly depends on the gas composition. 3 distinct regions: 1) Blue: [C] < [O] - no D growth, 2) White: C-O tie line [C] = [O] – D growth, 3) Red: [C] > [O], non-diamond C growth Bachmann triangle diagram. P. K. Bachmann et al, Mater. Res. Soc. Symp. Proc., 1994, 339 , 267.
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Common reactors for CVD diamond growth: a) Hot filament
b) “NIRIM” Microwave Plasma c) “ASTE” Microwave Plasma
d) DC Arc Jet Plasma torch
Any physical process
creating atomic H & CHx radicals can be used in Image of Dr. Paul May, University of Bristol
CVD growth of diamond.
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From website of Bristol University ▪ Typical growth rate: 1 μm/hour ▪ Large deposition area ~1 m² Drawbacks: Filament carburization & embrittlement D contamination by filament material
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Hydrocarbons activation by MW created by magnetron, frequency 2.45 GHz (standard components); Gas content: wide variety; P < 50 Torr; large deposition area A. NIRIM MW (NIRIM - National Institute for Research in Inorganic Materials, Tsukuba, Japan) MW cross the gas stream in a quartz tube; the substrate is placed on a heater in the plasma area; low MW power < 1.5 kW, Drawbacks: ▪ Low deposition rate ~ 0.5 μm/h. ▪ Si contaminations in D ▪ MW absorption on the window ▪ Non-controlled T of the substrate nearby plasma B. AsteX MW (ASTeX: USA producer of CVD Sy) MW via an antenna through a quartz window; the chamber from stainless steel, high MW power >6 kW Advantages: high purity, high growth rate -10 μm/h
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▪ Gas consumption: (Ar-CH4-H2)~10-30 l l min. Effective gas decomposition provided by highspeed jet with a core T of ~ 40,000ºC ▪ High growth rates of >900 μm/h ▪ Small deposition area N. Ohtake, J. Electrochem.Soc., 137 (1990) 717 ▪ In the 1990s, Norton Co. (US) launched commercial production of diamond wafers up to 175 mm in diameter, thermal grade. K.J. Gray, Diamond Relat. Mater., 8 (1999) 903
DC arc-jet Sy, 14 kW
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1. Ultrasonic Cavitation: ND are obtained by ultrasonic treatment of a graphite suspension in various organic liquids at T=120°C and normal P. The yield of D is up to 10%. [Khachatryan, A.Kh., et al, Diam and Related Materials 2008,17(6)]. 2. Hydrothermal Synthesis: D particles and films are grown from ND & BN seeds at reaction of organic liquid (C2H3Cl3) with NaOH at T= 300 °C, P=1 GPa. [Sergiy Korablov et al, Mater. Lett., 2006, 60].
3. Electrolysis of acetates: ammonium acetate in acetic acid at T=70-75 °C at voltage 10-100 Hz, peak 60 V [P. Aublanc et al, Diam and Related Materials, 2001, 10]. 4. Ion Bombardment: bombardment of CNT with double ions resulted in the synthesis of ND. [Wang Z.-X. et al, Wuli Xuebao 2007, 56, 4829–4833].
5. High-Energy Ball Milling: ND were obtained by the milling of pure graphite powder with 40 chrome coated steal balls (diameter 14 mm) in a planetary highenergy ball mill with a rotation speed of 800 rpm in He gas at RT during 28 hours. M. Sherif El-Eskandarany, J. of Materi Eng and Perform, June 2017,26-6]
6. Pulse Laser Ablation: treatment of graphite particles and substrates with laser beams of high power density in liquid results in ND synthesis (~5 wt.%). [G. W. Yang, 2012 ”Technology & Engineering”]
All methods were found not economical.
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▪ ND can be produced by the milling of polycrystalline D of HPHT or CVD synthesis. Instead high-energy ball milling in planetary mill with metallic beads (leading to metal contaminations) the following process was proposed by J.-P. Boudou et al: 1. Nitrogen jet milling autogenous micronization [HOSOKAWA ALPINE Aktiengesellschaft, https://www.hosokawa-alpine.com] 97% of particles sizes < 2 μm. 2. Ball milling in argon in a planetary ball mill [FRITSCH GmbH, http://www.fritschmilling.com ]
3. Purification by acid treatment and fractionalization by centrifugation [J.-P. Boudou et al, Nanotechnology, 20(23) 2009]
▪ Advantages in comparison with detonation ND synthesis:
1) HPHT and CVD can be doped for obtaining specific properties, particularly high photo-luminescence caused by embedded N-V or Si-V centers into D lattice. 2) Milling of HPHT and CVD D enables to produce ND of various sizes. ▪ Disadvantages:
1) too wide size distribution, 2) insufficient purity, 3) high cost
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Ray Techniques fabricates ND by proprietary technology which includes:
1. Synthesis ND by laser assisted techniques - Light Hydro-Dynamic Pulse (LHDP).
Laser treatment
Ash + Wax TARGET
IP protection Lab production Highest quality Initial sales “Green” & precise process
DIAMOND nanoparticles
2. ND surface modification; production of functionalized ND powders and stable highly dispersed nano-fluids based on various solvents
Know-how High efficiency
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LHDP can be attributed to the form of Pulse Laser Ablation in Liquid (PLAL)
Lens
Laser beam
2 novelties leaded to the output increase: 1) multi-component target instead of graphite (chemical mechanism?); 2) focusing laser beam at some predicted distance from the target
Liquid Shock wave Predicted distance from focus to target Specially prepared multicomponent hydrocarbon target Liquid reservoir Automatic table X-Y-Z
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1.
Purity: metal free, incombustible residue of RayND non-detectable,
(less than the accuracy of the instrument - 0.02 wt. %) For comparison: incombustible residue of DND: 0.4 - 8 wt. % 2.
Diamond structure sp3 on ND surface in RayND up to 72 %; in DND 23 % of the surface area (XPS analysis)
3.
Homogeneity: lower particle size distribution
4.
Cost efficiency: low cost in mass production
5.
Controlled process → constancy of properties Possibility to provide desired ND features (crystalline size, optic properties, surface chemistry and desired reactivity)
In-vivo applications
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▪ Aston-RAY CARTHER cooperation in the field of ND manufacturing enabled to submit a new project: Production of Advanced NanoDiamond Additives (PANDA)
▪ The goal: the development of full industrial technological chain for fabrication highly pure and uniform ND and efficient ND additives for diverse applications including bio-medicine (cancer treatment, early diagnostics, cell imaging) ▪ The frame: Horizon 2020 program H2020-SMEInst-2016-2017 ▪ Phase 1 aimed at feasibility study (use fs laser for ND synthesis) and writing Business Plan for phase 2. ▪ Technological, practical and economic viability of RAY’s process scaling was investigated and confirmed. Industrial equipment for ND production with the capability of 100 kg per month has been selected.
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PANDA project
Scaling of ND synthesis enables 200-fold increase in the output & significant cost reduction. Targeted cost:
