Synthesis of diamond films on Hastelloy

1992 ◽  
Vol 7 (10) ◽  
pp. 2785-2790 ◽  
Author(s):  
V.P. Godbole ◽  
J. Narayan
Keyword(s):  
Diamond Film ◽  
Composite Layer ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Diamond Growth ◽  
Chemical Vapor Deposition Method ◽  
Nucleation Sites ◽  
Higher Temperature ◽  
Lower Temperature ◽  
Hot Filament

We have developed a two-step hot filament chemical vapor deposition method to form polycrystalline films of diamond on Hastelloy substrates. The first step at a lower temperature results in the deposition of a composite layer of carbon, diamond-like carbon, and diamond, which provide nucleation sites for diamond growth in the second step at a higher temperature. To obtain a cleaner amorphous carbon-free diamond film, we introduced an intermediate hydrogen etching step. Using this procedure, we have obtained high quality polycrystalline diamond film on Hastelloy substrates, as characterized by scanning electron microscopy and Raman measurements.

The Effects of Chloromethane on Diamond Nucleation and Growth in a Hot-filament Chemical Vapor Deposition Reactor

1998 ◽  
Vol 13 (9) ◽  
pp. 2498-2504 ◽  
Author(s):  
Jih-Jen Wu ◽  
Franklin Chau-Nan Hong
Keyword(s):  
Film Growth ◽  
Chemical Vapor ◽  
Nucleation And Growth ◽  
Diamond Growth ◽  
Nucleation Density ◽  
Diamond Grit ◽  
Diamond Nucleation ◽  
Nucleation Sites ◽  
Lower Temperature ◽  
Hot Filament

The effects of chloromethane on diamond nucleation and growth were studied by employing laser reflective interferometry. Chloromethane enhances the film-growth rate only slightly compared to methane. However, chloromethane greatly enhances the nucleation density and shortens the film-forming stage, more significantly at a lower temperature. Thus, chloromethane facilitates the low temperature growth mainly through the enhancement of nucleation. Nucleation density is strongly dependent on the compositions of H atoms and carbon species prior to diamond growth. The residual diamond seeds by diamond-grit scratching are suggested to be the major nucleation sites. Chloromethane can enhance diamond nucleation by protecting the residual seeds from being etched by H atoms.

Examination of the material properties and performance of thin-diamond film cutting tool inserts produced by arc-jet and hot filament chemical vapor deposition

1996 ◽  
Vol 11 (7) ◽  
pp. 1765-1775 ◽  
Author(s):  
James M. Olson ◽  
Michael J. Dawes
Keyword(s):  
Wear Resistance ◽  
Chemical Vapor Deposition ◽  
Diamond Film ◽  
Vapor Deposition ◽  
Cutting Tool ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
And Performance ◽  
Hot Filament

Thin diamond film coated WC-Co cutting tool inserts were produced using arc-jet and hot-filament chemical vapor deposition. The diamond films were characterized using SEM, XRD, and Raman spectroscopy to examine crystal structure, fracture mode, thickness, crystalline orientation, diamond quality, and residual stress. The performance of the tools was evaluated by comparing the wear resistance of the materials to brazed polycrystalline diamond-tipped cutting tool inserts (PCD) while machining A390 aluminum (18% silicon). Results from the experiments carried out in this study suggest that the wear resistance of the thin diamond films is primarily related to the grain boundary strength, crystal orientation, and the density of microdefects in the diamond film.

Oxidation of diamond films synthesized by hot filament assisted chemical vapor deposition

1990 ◽  
Vol 5 (11) ◽  
pp. 2483-2489 ◽  
Author(s):  
K. Tankala ◽  
T. DebRoy ◽  
M. Alam
Keyword(s):  
Microwave Plasma ◽  
Synthetic Diamond ◽  
Natural Diamond ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Low Oxygen ◽  
Before And After ◽  
Lower Temperature ◽  
Hot Filament

Oxidation of polycrystalline diamond films on (111) Si wafers in air at temperatures up to 1073 K was investigated by thermogravimetry. The diamond films before and after partial oxidation were characterized by optical and scanning electron microscopy, x-ray, infrared, and Raman spectroscopy. The oxidation of synthetic diamond films started at a lower temperature than that for natural diamond. The rates of oxidation of the diamond films synthesized by the hot filament and the microwave plasma methods were intermediate between the rates of oxidation of the 111 and 100 planes of natural diamond crystals. The apparent activation energy for the oxidation of the synthetic diamond films agreed well with that for the oxidation of natural diamond via diamond to graphite transition at low oxygen pressures.

scholarly journals Unusual Dependence of the Diamond Growth Rate on the Methane Concentration in the Hot Filament Chemical Vapor Deposition Process

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 426
Author(s):  
Byeong-Kwan Song ◽  
Hwan-Young Kim ◽  
Kun-Su Kim ◽  
Jeong-Woo Yang ◽  
Nong-Moon Hwang
Keyword(s):  
Growth Rate ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Methane Concentration ◽  
Chemical Vapor ◽  
Diamond Growth ◽  
Lower Growth ◽  
Filament Temperature ◽  
Diamond Phase ◽  
Hot Filament

Although the growth rate of diamond increased with increasing methane concentration at the filament temperature of 2100 °C during a hot filament chemical vapor deposition (HFCVD), it decreased with increasing methane concentration from 1% CH4 –99% H2 to 3% CH4 –97% H2 at 1900 °C. We investigated this unusual dependence of the growth rate on the methane concentration, which might give insight into the growth mechanism of a diamond. One possibility would be that the high methane concentration increases the non-diamond phase, which is then etched faster by atomic hydrogen, resulting in a decrease in the growth rate with increasing methane concentration. At 3% CH4 –97% H2, the graphite was coated on the hot filament both at 1900 °C and 2100 °C. The graphite coating on the filament decreased the number of electrons emitted from the hot filament. The electron emission at 3% CH4 –97% H2 was 13 times less than that at 1% CH4 –99% H2 at the filament temperature of 1900 °C. The lower number of electrons at 3% CH4 –97% H2 was attributed to the formation of the non-diamond phase, which etched faster than diamond, resulting in a lower growth rate.

Effect of Argon during Diamond Deposition by Hot Filament Chemical Vapor Deposition

2016 ◽  
Vol 869 ◽  
pp. 721-726 ◽  
Author(s):  
Divani C. Barbosa ◽  
Ursula Andréia Mengui ◽  
Mauricio R. Baldan ◽  
Vladimir J. Trava-Airoldi ◽  
Evaldo José Corat
Keyword(s):  
Growth Rate ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Diamond Growth ◽  
Gas Mixture ◽  
X Ray Diffraction ◽  
Hot Filament ◽  
Argon Content

The effect of argon content upon the growth rate and the properties of diamond thin films grown with different grains sizes are explored. An argon-free and argon-rich gas mixture of methane and hydrogen is used in a hot filament chemical vapor deposition reactor. Characterization of the films is accomplished by scanning electron microscopy, Raman spectroscopy and high-resolution x-ray diffraction. An extensive comparison of the growth rate values and films morphologies obtained in this study with those found in the literature suggests that there are distinct common trends for microcrystalline and nanocrystalline diamond growth, despite a large variation in the gas mixture composition. Included is a discussion of the possible reasons for these observations.

Sign in / Sign up

Export Citation Format

Share Document