Diamond Coated WC Tools for Machining Wood and Particle Board

2001 ◽  
Vol 697 ◽  
Author(s):  
Raghuveer S. Makala ◽  
S.N. Yoganand ◽  
K. Jagannadham ◽  
R.L. Lemaster ◽  
J. Bailey
Keyword(s):  
Contact Area ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Cutting Edge ◽  
Particle Board ◽  
Essential Factor ◽  
Plasma Chemical Vapor Deposition ◽  
Coated Tools ◽  
Film Adhesion

AbstractDiamond coating was provided to improve the performance of WC-Co tools used in machining wood and particle board. Microwave plasma chemical vapor deposition was used to deposit diamond using a gas mixture with CH4: H2 in the ratio 0.5: 100 at a temperature of 900°C. The microwave energy was set at 900W and a pressure of 35Torr was maintained in the chamber. An essential factor that determines the life of polycrystalline diamond coated tools is poor film adhesion. To counter this problem, we have developed a process that includes etching away cobalt from surface regions, treatment with H2 plasma and use of TiN/ TiC intermediate and embedding layers. The TiN/ TiC layers were deposited by reactive magnetron sputtering. These layers embed diamond crystallites and improve adhesion, and in addition act as good diffusion barriers for Co. The diamond coated and uncoated tools have been characterized in the as deposited conditions and after prescribed wear by machining particle board using SEM and X-ray mapping. It was also found that the limited contact area with diamond on the cutting edge affects the adhesion of the coating. Improvement in contact area by providing a larger radius to the cutting edge is discussed.

High Resolution Tem Study of Diamond Formation on Silicon and Molybdenum Field Emitter Surfaces

1994 ◽  
Vol 354 ◽  
Author(s):  
A. F. Myers ◽  
J. Liu ◽  
W. B. Choi ◽  
G. J. Wojak ◽  
J. J. Hren
Keyword(s):  
High Resolution ◽  
Diamond Film ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Plasma Chemical Vapor Deposition ◽  
Field Emitters ◽  
High Resolution Tem ◽  
Diffraction Patterns ◽  
Polycrystalline Diamond Film

AbstractDiamond is an attractive material for coating microfabricated metal and semiconductor field emitters, since it enhances the stability and emission characteristics of the emitter. In the present study, polycrystalline diamond thin films were grown on silicon and molybdenum field emitters by microwave plasma chemical vapor deposition, using the bias-enhanced nucleation technique. High resolution transmission electron microscopy (TEM) was used to analyze the morphology of the diamond film and the structure of the diamond/emitter interface. Electron diffraction patterns and high resolution images indicate the presence of a polycrystalline diamond film, as well as a polycrystalline SiC layer between the diamond film and the Si emitter. A carbide interlayer was also found to exist between the diamond and the Mo emitter surface. Parallel electron energy loss spectroscopy confirms the TEM identification of a polycrystalline diamond film.

Electrical Properties of Hydrogen Terminated P-Type Diamond Film

2010 ◽  
Vol 663-665 ◽  
pp. 625-628
Author(s):  
Fu Yuan Xia ◽  
Lin Jun Wang ◽  
Jian Huang ◽  
Ke Tang ◽  
Ji Jun Zhang ◽  
...  
Keyword(s):  
Carrier Concentration ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Plasma Chemical ◽  
Plasma Chemical Vapor Deposition ◽  
P Type ◽  
Effect Method

Undoped high quality polycrystalline diamond films were grown by the microwave plasma chemical vapor deposition (MPCVD) method. The effects of hydrogen plasma treatment and vacuum annealing process on the p-type behavior of diamond films were investigated by the Hall effect method. The sheet carrier concentration increased and the sheet resistivity decreased with the treating time of hydrogen plasma and a stable value was achieved finally. After annealing the samples in vacuum at temperature above 600 °C, the sheet carrier concentration dropped dramatically. The origin of this hydrogen terminated p-type conductive layers is also discussed.

Piezoresistivity of Polycrystalline Diamond Films

1992 ◽  
Vol 283 ◽  
Author(s):  
Der-Rern Wur ◽  
Jim L. Davidson
Keyword(s):  
High Temperature ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Gauge Factor ◽  
Plasma Chemical ◽  
Plasma Chemical Vapor Deposition ◽  
Boron Doped ◽  
Radiation Hard ◽  
Polycrystalline Diamond Film

ABSTRACTPolycrystalline diamond film (PDF) is known for its high power, high temperature, and radiation hard potential. The interest in piezoresistivity of PDF is that it is a candidate for high temperature sensing (e.g., pressure sensor).Piezoresistivity measurements were taken of boron-doped PDF grown by microwave-plasma chemical vapor deposition(CVD). Three substrates, silicon, aluminum nitride and tungsten were used. Films were detached from these substrates, then attached to a ceramic substrate. The piezoresistivity varies, dependent on the original host substrate. For example, at room temperature, the PDF film from tungsten has a greater gauge factor, around 75. The carrier activation energy of this film, determined from log R(l/T), was nominally 0.25eV.Combining thick film technology and CVD processes, patterned B-doped PDF has been achieved monolithically on A1N substrates. The characteristics of this configuration is being investigated and will be presented.

scholarly journals Isotope Effect in Thermal Conductivity of Polycrystalline CVD-Diamond: Experiment and Theory

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 322
Author(s):  
Alexander V. Inyushkin ◽  
Alexander N. Taldenkov ◽  
Victor G. Ralchenko ◽  
Andrey P. Bolshakov ◽  
Alexander V. Khomich
Keyword(s):  
Thermal Conductivity ◽  
Chemical Vapor Deposition ◽  
Isotopic Composition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Cvd Diamond ◽  
Plasma Chemical Vapor Deposition

We measured the thermal conductivity κ(T) of polycrystalline diamond with natural (natC) and isotopically enriched (12C content up to 99.96 at.%) compositions over a broad temperature T range, from 5 to 410 K. The high quality polycrystalline diamond wafers were produced by microwave plasma chemical vapor deposition in CH4-H2 mixtures. The thermal conductivity of 12C diamond along the wafer, as precisely determined using a steady-state longitudinal heat flow method, exceeds much that of the natC sample at T>60 K. The enriched sample demonstrates the value of κ(298K)=25.1±0.5 W cm−1 K−1 that is higher than the ever reported conductivity of natural and synthetic single crystalline diamonds with natural isotopic composition. A phenomenological theoretical model based on the full version of Callaway theory of thermal conductivity is developed which provides a good approximation of the experimental data. The role of different resistive scattering processes, including due to minor isotope 13C atoms, defects, and grain boundaries, is estimated from the data analysis. The model predicts about a 37% increase of thermal conductivity for impurity and dislocation free polycrystalline chemical vapor deposition (CVD)-diamond with the 12C-enriched isotopic composition at room temperature.

Development of flat, smooth (100) faceted diamond thin films using microwave plasma chemical vapor deposition

1997 ◽  
Vol 12 (7) ◽  
pp. 1796-1805 ◽  
Author(s):  
Andrew L. Yee ◽  
H. C. Ong ◽  
L. M. Stewart ◽  
R. P. H. Chang
Keyword(s):  
Microwave Plasma ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Growth Conditions ◽  
Fiber Texture ◽  
Spiral Growth ◽  
Carbon Phase ◽  
Growth Step ◽  
Plasma Chemical Vapor Deposition ◽  
Novel Approach

A novel approach has been used to develop (100) faceted diamond films with flat, smooth surfaces. A morphological study of the early stages of growth behavior of (100) homoepitaxial films versus process temperature and methane percentage was carried out using atomic force microscopy. The results showed that spiral growth features and penetration twin density were dominant for growth conditions not well suited for (100) growth. Optimized process parameters were found to proceed via a step mechanism consistent with ledge growth on (2 × 1) reconstructed (100) diamond surfaces. These optimized conditions were then applied to growth of polycrystalline diamond on pretreated silicon substrates. A unique octahedral faceted film resulted, indicating strong preference for growth in the 〈100〉 direction. Scanning electron microscopy, x-ray diffraction, and Raman spectroscopy were used to assess film morphology, internal fiber texture, and carbon phase, respectively. A second stage growth step was used to flatten the surface topography to achieve the desired (100) flat tile-like morphology. This smooth (100) surface exhibited enhanced tribological performance compared to a typical randomly textured diamond film.

Sign in / Sign up

Export Citation Format

Share Document