scholarly journals Improving Pressure–Velocity Limit of Mechanical Seal with Polycrystalline Diamond Coating

2020 ◽  
Vol 10 (17) ◽  
pp. 6090
Author(s):  
Daidong Guo ◽  
Ningning Cai ◽  
Guoping Wu ◽  
Fangmin Xie ◽  
Shouhong Tan ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Deposition Process ◽  
Operating Conditions ◽  
Mechanical Seal ◽  
Initial Deposition ◽  
Hot Filament ◽  
Harsh Conditions ◽  
Sintered Silicon

Polycrystalline diamond (PCD)-coated mechanical seal rings were prepared by hot filament chemical vapor deposition (HFCVD) on graphite-loaded silicon carbide (GSiC) substrates. From the initial deposition process, the diamond first nucleated and then grew into a dense coating with grain size of 4 μm and thickness of 12.3 μm. The well-grown PCD coating, as confirmed by Raman spectroscopy and X-ray diffractometry, significantly improves the pressure–velocity limit of the mechanical seal applied in harsh operating conditions, no matter whether for a hard-to-soft mating combination or a hard-to-hard mating combination. Comparing GSiC against sintered silicon carbide (SSiC) combination (GSiC/SSiC), GSiC against graphite combination (GSiC/graphite) and PCD against graphite combination (PCD/graphite), PCD against SSiC combination (PCD/SSiC) shows the highest pressure velocity (PV) limit of 42.31 MPa·m/s with 4 kN loading at 4500 rpm rotation speed. An extremely low and stable friction coefficient and super mechanical properties under harsh conditions can be approved as the source of the high PV limit of PCD coating. A mechanical seal with PCD coating can be used for more demanding applications.

Effect of Mechanical Stress on Polycrystalline Diamond Schottky Diode I-V Characteristics

1992 ◽  
Vol 270 ◽  
Author(s):  
G. Zhao ◽  
E. M. Charlson ◽  
E. J. Charlson ◽  
T. Stacy ◽  
J. Meese ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Schottky Diodes ◽  
Forward Bias ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Deposition Process ◽  
Stress Sensitivity ◽  
Stress Effect ◽  
Mechanical Sensors ◽  
Hot Filament

ABSTRACTSchottky diodes to be used for mechanical stress effect studies were fabricated using aluminum contacts to polycrystalline diamond thin films grown by a hot-filament assisted chemical vapor deposition process. Compressive stress was found to have a large effect on the forward biased current-voltage characteristics of the diode. At selected values of constant forward biased current, a linear relationship between voltage and stress, for stress less than 10 N was observed. The stress sensitivity of the diode was as high as 0.74 V/N at 1 mA forward bias. This study shows that polycrystalline diamond Schottky diodes are stress sensitive devices and have potential as mechanical sensors.

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.

Theoretical Study of Gas-Phase Thermodynamics Relevant to Silicon Carbide Chemical Vapor Deiposition

1991 ◽  
Vol 250 ◽  
Author(s):  
Mark D. Allendorf ◽  
Carl F. Melius
Keyword(s):  
Silicon Carbide ◽  
Gas Phase ◽  
Theoretical Study ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Equilibrium Calculations

AbstractEquilibrium calculations are reported for conditions typical of silicon carbide (SiC) deposition from mixtures of silane and hydrocarbons. Included are 34 molecules containing both silicon and carbon, allowing an assessment to be made of the importance of organosilicon species (and organosilicon radicals in particular) to the deposition process. The results are used to suggest strategies for improved operation of SiC CVD processes.

Measurement of The Activation Energy in Phosphorous Doped Polycrystalline Diamond Thin Films Grown on Silicon Substrates by Hot Filament Chemical Vapor Deposition

1996 ◽  
Vol 423 ◽  
Author(s):  
S. Mirzakuchaki ◽  
H. Golestanian ◽  
E. J. Charlson ◽  
T. Stacy
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Silicon Substrates ◽  
Boron Doped Diamond ◽  
Diamond Thin Films ◽  
Hot Filament

AbstractAlthough many researchers have studied boron-doped diamond thin films in the past several years, there have been few reports on the effects of doping CVD-grown diamond films with phosphorous. For this work, polycrystalline diamond thin films were grown by hot filament chemical vapor deposition (HFCVD) on p-type silicon substrates. Phosphorous was introduced into the reaction chamber as an in situ dopant during the growth. The quality and orientation of the diamond thin films were monitored by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Current-voltage (I-V) data as a function of temperature for golddiamond film-silicon-aluminum structures were measured. The activation energy of the phosphorous dopants was calculated to be approximately 0.29 eV.

Characterization of undoped and boron-doped polycrystalline diamond films synthesized by hot-filament chemical vapor deposition using methanol

1994 ◽  
Vol 3 (4-6) ◽  
pp. 618-622 ◽  
Author(s):  
Takashi Sugino ◽  
Kiyoshi Karasutani ◽  
Fumihiro Mano ◽  
Hiroya Kataoka ◽  
Junji Shirafuji ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Boron Doped ◽  
Hot Filament

Effects of Various Seeding Methods on Multi-Layered Diamond Coatings Deposited via Hot Filament Chemical Vapor Deposition

2013 ◽  
Vol 845 ◽  
pp. 36-40
Author(s):  
Tze Mi Yong ◽  
Esah Hamzah
Keyword(s):  
Natural Diamond ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Columnar Structure ◽  
X Rays ◽  
Diamond Coating ◽  
Diamond Coatings ◽  
Good Adhesion ◽  
Hot Filament ◽  
Xrd Method

Multi-layer alternating nanocrystalline diamond (NCD) layer and polycrystalline diamond (PCD) layer was successfully deposited on pretreated tungsten carbide (WC) substrates with various seeding sizes (<0.1μm synthetic, <0.5μm synthetic, <0.25μm natural, <0.5μm natural, and <1μm natural) diamond with and without hammering by silicon carbide. X-rays penetrate through the coating to the substrate from XRD method was able to show strong peaks of diamond relative to WC despite the diamond film being 4μm thick only. It is found that substrates with no hammering produce stronger signals. The coating was cross sectioned and analysed using field emission scanning electron microscopy showing the multi-layer with NCD grains that has coalesced and columnar structure for PCD. None of the diamond coating delaminated during cross sectioning showing good adhesion. Raman was able to capture data from the 1-1.6μm thick NCD layer only while AFM measured the extreme low roughness of the NCD surface.

Optimization of Chemical Vapor Deposition Process

2006 ◽  
Author(s):  
Pradeep George ◽  
Hae Chang Gea ◽  
Yogesh Jaluria
Keyword(s):  
Thin Film ◽  
Chemical Vapor Deposition ◽  
Response Surface ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Transport Processes ◽  
Operating Conditions ◽  
Design Parameters ◽  
Large Area

Chemical Vapor Deposition (CVD) process is simulated and optimized for the deposition of a thin film of silicon from silane. The key focus is on the rate of deposition and on the quality of the thin film produced. The intended application dictates the level of quality need for the film. Proper control of the governing transport processes results in large area film thickness and composition uniformity. A vertical impinging CVD reactor is considered. The goal is to optimize the CVD system. The effect of important design parameters and operating conditions are studied using numerical simulations. Then Compromise Response Surface Method (CRSM) is used to model the process over a range of susceptor temperature and inlet velocity of the reaction gases. The resulting response surface is used to optimize the CVD system.

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.

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