Effects of CH4 Concentration on CVD Diamond Coatings Deposited on Cemented Carbide Cutting Cools

2006 ◽  
Vol 532-533 ◽  
pp. 480-483 ◽  
Author(s):  
Wen Zhuang Lu ◽  
Dun Wen Zuo ◽  
Min Wang ◽  
Feng Xu
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Great Influence ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Cemented Carbide ◽  
Diamond Coatings ◽  
Ch4 Concentration

Chemical vapor deposition (CVD) diamond coatings were deposited on cemented carbide cutting cools by an electron-assisted hot filament chemical vapor deposition (EACVD) equipment developed by the authors. The CVD diamond coatings were studied by Scanning Electron Microscope (SEM) and Raman Scattering Spectroscopy (Raman). The experimental results show that CH4 concentration in the source gas performs great influence on the micro-structure, surface roughness, composition, residual stress and adhesion of the CVD diamond coatings. The increase of CH4 concentration results the change of diamond crystal from {111} orientation to {100} orientation, the decrease of the surface roughness and the increase of sp2 carbon in the CVD diamond coatings. A residual compressive stress exists in the CVD diamond coatings. The residual stress decreases with increasing CH4 concentration. A higher or lower CH4 concentration tends to reduce adhesion stress of the continuous CVD diamond coatings.

DIAMOND DEPOSITION ON WC/Co ALLOY WITH A MOLYBDENUM INTERMEDIATE LAYER

2005 ◽  
Vol 12 (04) ◽  
pp. 499-504
Author(s):  
SHA LIU ◽  
ZHI-MING YU ◽  
DAN-QING YI
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Intermediate Layer ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Diamond Growth ◽  
Diamond Coatings ◽  
Sputter Deposited ◽  
Diamond Grain

It is known that in the condition of chemical vapor deposition (CVD) diamond process, molybdenum is capable of forming carbide known as the "glue" which promotes growth of the CVD diamond, and aids its adhesion by (partial) relief of stresses at the interface. Furthermore, the WC grains are reaction bonded to the Mo 2 C phase. Therefore, molybdenum is a good candidate material for the intermediate layer between WC–Co substrates and diamond coatings. A molybdenum intermediate layer of 1–3 μm thickness was magnetron sputter-deposited on WC/Co alloy prior to the deposition of diamond coatings. Diamond films were deposited by hot filament chemical vapor deposition (HFCVD). The chemical quality, morphology, and crystal structure of the molybdenum intermediate layer and the diamond coatings were characterized by means of SEM, EDX, XRD and Raman spectroscopy. It was found that the continuous Mo intermediate layer emerged in spherical shapes and had grain sizes of 0.5–1.5 μm after 30 min sputter deposition. The diamond grain growth rate was slightly slower as compared with that of uncoated Mo layer on the WC–Co substrate. The morphologies of the diamond films on the WC–Co substrate varied with the amount of Mo and Co on the substrate. The Mo intermediate layer was effective to act as a buffer layer for both Co diffusion and diamond growth.

Ultra-smooth and robust graphene-based hybrid anode for high-performance flexible organic light-emitting diodes

2021 ◽  
Author(s):  
zhikun zhang ◽  
lianlian xia ◽  
Lizhao Liu ◽  
Yuwen Chen ◽  
zuozhi wang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
High Performance ◽  
Light Emitting Diodes ◽  
Chemical Vapor ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light ◽  
Large Particles

Large surface roughness, especially caused by the large particles generated during both the transfer and the doping processes of graphene grown by chemical vapor deposition (CVD) is always a critical...

A spectroscopic study of optical centers in diamond grown by microwave-assisted chemical vapor deposition

1990 ◽  
Vol 5 (11) ◽  
pp. 2507-2514 ◽  
Author(s):  
A. T. Collins ◽  
M. Kamo ◽  
Y. Sato
Keyword(s):  
Chemical Vapor Deposition ◽  
Radiation Damage ◽  
Single Crystals ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Edge Emission ◽  
Microwave Assisted ◽  
Bright Blue ◽  
Methane Concentrations

Absorption and cathodoluminescence spectra have been recorded for single crystals of diamond and polycrystalline films of diamond, grown by microwave-assisted chemical vapor deposition (CVD) using methane and hydrogen. The investigation has been carried out to see to what extent the properties of CVD diamond are similar to those of conventional diamond, and to what extent they are unique. Studies have been made of the as-grown material, which has not been intentionally doped, and also samples that have been subjected to radiation damage and thermal annealing. The single crystals grown using methane concentrations of 0.5 to 1.0% exhibit bright blue “band A” emission and also intense edge emission, similar to the cathodoluminescence spectra of some natural type IIa diamonds. This implies that the crystals are relatively free from structural and chemical defects, a conclusion which is reinforced by the absence of any zero-phonon lines in the absorption spectra of crystals which have been subjected to radiation damage and annealing at 800 °C. Before radiation damage the spectrum does, however, reveal an absorption which increases progressively to higher energies, and which may be associated with sp2-bonded carbon. The Cathodoluminescence spectra after radiation damage indicate that the crystals contain some isolated nitrogen, and the detection of H3 luminescence, following thermal annealing at 800 °C, demonstrates for the first time that these samples contain small concentrations of nitrogen pairs. All of the polycrystalline films, grown using methane concentrations between 0.3 and 1.5%, have an absorption which increases progressively to higher energies, and which again is attributed to sp2-bonded carbon. This absorption is stronger in the films grown using higher methane concentrations. Films grown at a methane concentration of 0.3% also exhibit bright blue cathodoluminescence, although the edge emission is undetectably weak. The use of higher methane concentrations produces films with evidence in the cathodoluminescence spectra of nitrogen + vacancy and nitrogen + interstitial complexes, as well as optical centers unique to CVD diamond. One particular defect produces an emission and absorption line at 1.681 eV. By implanting conventional diamonds with 29Si ions it has been confirmed that this center involves silicon, and it has been shown that the 1.681 eV luminescence is relatively more intense in implanted diamonds which have a high concentration of isolated nitrogen.

Metastable nanosized diamond formation from a C-H-O fluid system

2010 ◽  
Vol 25 (12) ◽  
pp. 2336-2340 ◽  
Author(s):  
S.K. Simakov
Keyword(s):  
Experimental Data ◽  
Chemical Vapor Deposition ◽  
Synthesis Gas ◽  
Vapor Deposition ◽  
Present Model ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Diamond Synthesis ◽  
Diamond Formation ◽  
Fluid System

The model of nanosized diamond particles formation at metastable P-T parameters from a C-H-O fluid system is presented. It explains the hydrothermal formation and growth of diamond and the specifics of chemical vapor deposition (CVD) diamond synthesis gas mixtures at low P-T parameters. Further, the model explains the genesis of interstellar nanodiamond formations in space and the genesis of metamorphic microdiamonds in shallow depth Earth rocks. In contrast to models where many possible reactions are considered, the present model makes the simplest possible assumptions about the key processes, and is then able to account for various tendencies seen in experimental data.

A study on the residual stress measurement methods on chemical vapor deposition diamond films

1998 ◽  
Vol 13 (11) ◽  
pp. 3027-3033 ◽  
Author(s):  
Jung Geun Kim ◽  
Jin Yu
Keyword(s):  
Residual Stress ◽  
Chemical Vapor Deposition ◽  
Tensile Stress ◽  
Residual Stresses ◽  
Vapor Deposition ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Peak Shift ◽  
Intrinsic Stress ◽  
Chemical Vapor Deposition Diamond

Diamond films were deposited on the p-type Si substrate with the hot filament chemical vapor deposition (HFCVD). Residual stresses in the films were measured in air by the laser curvature, the x-ray diffraction (XRD) dϕψ − sin2ψ, and the Raman peak shift methods. All of the measuring methods showed similar behaviors of residual stress that changed from a compressive to a tensile stress with increasing the film thickness. However, values of residual stresses obtained through the Raman and XRD methods were 3–4 times higher than those of the curvature method. These discrepancies involved the setting of materials constants of CVD diamond film, and determination of a peak shifting on the XRD and Raman method. In order to elucidate the disparity, we measured a Young's moduli of diamond films by using the sonic resonance method. In doing so, the Raman and XRD peak shift were calibrated by bending diamond/Si beams with diamond films by a known amount, with stress levels known a priori from the beam theory, and by monitoring the peak shifts simultaneously. Results of each measuring method showed well coincidental behaviors of residual stresses which have the stress range from −0.5 GPa to +0.7 GPa, and an intrinsic stress was caused about +0.7 GPa with tensile stress.

Nanostructured Diamond Coatings for Dry Drilling

2009 ◽  
Author(s):  
Kevin Chou ◽  
Raymond Thompson ◽  
Feng Qin ◽  
Dustin Nolen ◽  
Chao Miao
Keyword(s):  
Chemical Vapor Deposition ◽  
Residual Stresses ◽  
Vapor Deposition ◽  
Performance Enhancement ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Gas Mixture ◽  
Diamond Coatings ◽  
Thermal Mismatch ◽  
Dry Drilling

In this study, nanostructured diamond (NSD) films were grown, by microwave plasma assisted chemical vapor deposition (MP-CVD) technology, on WC-Co drills for performance enhancement in dry drilling of A390 alloys. Surface cobalt was removed by a well-controlled precision etching process. H2/CH4 gas mixture with a small amount of N2 was applied to produce NSD films. Moreover, slight hone was applied to the cutting edges prior to the NSD deposition to relieve residual stresses generated by thermal mismatch in depositions. The results show feasibility of dry drilling of A390 alloys by NSD coated drills, substantially outperforming carbide drills.

Effect of Deposition Temperature on Surface Roughness of Nanocrystalline Diamond Film

2012 ◽  
Vol 476-478 ◽  
pp. 2353-2356
Author(s):  
Wen Qi Dai ◽  
Lin Jun Wang ◽  
Jian Huang ◽  
Yi Feng Liu ◽  
Ke Tang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Chemical Vapor Deposition ◽  
Diamond Film ◽  
Vapor Deposition ◽  
Deposition Temperature ◽  
Chemical Vapor ◽  
Nanocrystalline Diamond ◽  
Different Temperatures ◽  
Hot Filament

Nanocrystalline diamond (NCD) films were synthesized by hot-filament chemical vapor deposition (HFCVD) method at different temperatures (600 °C, 620°C, 640°C and 660°C). The AFM and Raman analyses demonstrated that deposition temperature has a great effect on the surface roughness and quality of NCD films and 620°C is the temperature to grow NCD films with smooth surfaces.

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