From Micro to Nanometric Grain Size CVD Diamond Tools

2009 ◽  
Vol 1243 ◽  
Author(s):  
Flávia A. Almeida ◽  
Margarida Amaral ◽  
Ermelinda Salgueiredo ◽  
António J.S. Fernandes ◽  
Florinda M. Costa ◽  
...  
Keyword(s):  
Base Material ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Surface Finishing ◽  
Coated Tools ◽  
Drill Bits ◽  
Coated Tool ◽  
Wear Mode ◽  
Steel Aisi ◽  
Hot Filament

ABSTRACTCVD diamond coated tools are developed for applications as different as turning of cemented carbides and bone drilling. The diamond films are deposited by Hot Filament Chemical Vapor Deposition (HFCVD), with grain sizes varying from conventional micrometric (12 μm) to nanometric (< 100 nm) and film thickness up to 50 μm. Silicon nitride (Si3N4) ceramics are chosen for the base material in order to guarantee maximal adhesion. Both the micrometric and nanometric CVD diamond grades endure the cemented carbide turning showing slight cratering, having flank wear as the main wear mode. However, nanocrystalline diamond present the best behavior regarding cutting forces (<150 N) and tool wear (KM=30 μm, KT=2 μm and VB=110 μm) and workpiece surface finishing (Ra=0.2 μm). In the case of the dental drilling experiments, a polymeric laminated test block is used to simulate the human mandible and maxilla. The temperature rise during drilling is monitored to prevent overheating above 42–47 °C that is known to cause tissue death and implant failure. It is possible to drill with a CVD diamond Si3N4 coated tool with significantly lower forces (fourfold smaller), lower rise in temperature (4°C less), lower spindle speeds (100 rpm) and higher infeed rates (30 mm/min), when compared to the commercial steel (AISI 420) drill bits.

Improvement on the Cutting Performance of CVD Diamond Coated Drills in Drilling CFRP

2012 ◽  
Vol 499 ◽  
pp. 366-371 ◽  
Author(s):  
Jian Guo Zhang ◽  
Ben Wang ◽  
Fang Hong Sun ◽  
Hang Gao
Keyword(s):  
Thermal Conductivity ◽  
Wear Resistance ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Cutting Performance ◽  
Reinforced Plastics ◽  
Coated Tool ◽  
Hot Filament

Carbon fiber reinforced plastics (CFRP) is difficult to machine because of the extremely abrasive nature of the carbon fibers and its low thermal conductivity. CVD diamond films have many excellent properties such as wonderful wear resistance, high thermal conductivity and low friction coefficient, therefore depositing diamond films on the surface of drills is thought to be an effective way to elongate the lifetime of drills and improve the cutting performance. In this study, diamond films are deposited on the WC-Co drill using hot filament chemical vapor deposition (HFCVD) method. The results of characterization by the scanning electron microscope (SEM) and Raman spectrum indicate that the fabricated CVD diamond coated drill is covered with a layer of uniform and high-purity diamond films. The cutting performance of as-fabricated CVD diamond coated drill is evaluated in dry drilling CFRP, comparing with the uncoated WC-Co drill. The results demonstrate that the CVD diamond coated drill exhibits much stronger wear resistance. Its flank wear is about 50μm after drilling 30 holes, about one-third of that of WC-Co drill. Machining quality of the exit and internal wall of drilled holes shows better surface finish obtained by coated drill, which suggests that CVD diamond coated tool has great advantages in drilling CFRP.

Fabrication and Cutting Performance of CVD Diamond Coated Inserts with Different Coating Thickness in Dry Turning Aluminum Alloy

2012 ◽  
Vol 497 ◽  
pp. 73-77 ◽  
Author(s):  
Jian Guo Zhang ◽  
Liang Wang ◽  
Bin Shen ◽  
Fang Hong Sun
Keyword(s):  
Aluminum Alloy ◽  
Coating Thickness ◽  
Adhesive Wear ◽  
Cutting Tools ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Cutting Performance ◽  
Dry Turning ◽  
Coated Tools ◽  
Hot Filament

CVD diamond coated inserts with different coating thickness are fabricated using hot filament chemical vapor deposition (HFCVD) method. Scanning electron microscope (SEM) and Raman spectroscopy are introduced to characterize the diamond films. The cutting performance of as-fabricated CVD diamond coated inserts is evaluated in dry turning aluminum alloy. The uncoated WC-Co tool is also adopted in the cutting tests for the sake of comparability. The testing results show that diamond coated tools exhibit much better cutting performance. Coating thickness affects the characteristics of diamond coated cutting tools, the thicker of coating, the more adhesive chips, but the better delamination resistant. The uncoated WC-Co tool suffers adhesive wear for the built-up edge (BUE) breaking.

CVD Diamond Films Growth on Silicon Nitride Inserts (Si3N4) with High Nucleation Density by Functionalization Seeding

2012 ◽  
Vol 727-728 ◽  
pp. 1433-1438 ◽  
Author(s):  
R.A. Campos ◽  
A. Contin ◽  
Vladimir J. Trava-Airoldi ◽  
J.R. Moro ◽  
D.M. Barquete ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Diamond Film ◽  
Cutting Tools ◽  
Diamond Films ◽  
Base Material ◽  
Cvd Diamond ◽  
Nucleation Density ◽  
Force Microscopy ◽  
Low Thermal Expansion ◽  
Hot Filament

Silicon Nitride is largely used as the base material to manufacture cutting tools. Due to its low thermal expansion coefficient it is ideal candidate for CVD diamond deposition. In this work, we functionalized the surface of silicon nitride inserts (Si3N4) with a polymer (PDDA Poly (diallyldimethylamonium chloride - Mw 40000)) to promote seeding with nanodiamond particles. The seeding was performed in water slurry containing 4 nm diamond particles dispersed by PSS Poly (sodium4-styrenesulfonate) polymer. CVD diamond films, with high nucleation density, were deposited in a hot filament reactor. Film morphology was characterized by Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Diamond film quality was determined by Raman Spectroscopy. CVD diamond film adherence was evaluated using Rockwell C indentation.

scholarly journals The Hydrogenation Impact on Electronic Properties of p-Diamond/n-Si Heterojunctions

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6615
Author(s):  
Szymon Łoś ◽  
Kazimierz Fabisiak ◽  
Kazimierz Paprocki ◽  
Mirosław Szybowicz ◽  
Anna Dychalska ◽  
...  
Keyword(s):  
Diamond Films ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Cvd Diamond ◽  
Point Of View ◽  
Hydrogen Passivation ◽  
Temperature Dependent ◽  
Current Voltage ◽  
P Type ◽  
Hot Filament

The undoped polycrystalline diamond films (PDFs) have been deposited on n-type silicon (Si) by Hot Filament Chemical Vapor Deposition (HF CVD) technique. The reaction gases are a mixture of methane and hydrogen. The obtained PDFs were characterized by scanning electron microscopy (SEM) and Raman spectroscopy which, in addition to the diamond phase, also confirms the presence of sp2 hybridized carbon bonds. As-grown CVD diamond layers are hydrogen terminated and show p-type conductivity. The effect of the level of hydrogenation on the electrical properties of p-diamond/n-Si heterojunctions has been investigated by temperature dependent current–voltage (J-V/T) characteristics. The obtained results suggest that the energy distribution of interface states at the grain boundary (GB) subjected to hydrogenation becomes shallower, and the hole capture cross-section can be reduced. Hydrogenation can lead to a significant reduction of the GB potential barrier. These results can be interesting from the point of view of hydrogen passivation of GBs in microelectronics.

CVD Diamond Films as Wear-Resistant Coatings for Relief Valve Components in the Coal Liquefaction Equipment

2011 ◽  
Vol 175 ◽  
pp. 219-225 ◽  
Author(s):  
Xin Chang Wang ◽  
Bin Shen ◽  
Fang Hong Sun
Keyword(s):  
Fluid Velocity ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Coal Liquefaction ◽  
Valve Seat ◽  
Relief Valve ◽  
Wear Resistant ◽  
Mechanical And Tribological Properties ◽  
Hot Filament

Relief valves used in the coal liquefaction equipment are running in an extremely harsh environment with extraordinarily high temperature, high pressure differential, high fluid velocity as well as the intensely slurry flow erosion. The lifetime of relief valves is critically important to the reliability and running cost of the coal liquefaction equipment. Diamond film is potentially used as wear-resistant and protective coating for the relief valve components in coal liquefaction equipment due to its outstanding mechanical and tribological properties. In present study, a layer of high-quality diamond films are deposited on the working surface of conventional WC-Co cemented carbide relief valve components, using the hot filament chemical vapor deposition (HFCVD) technique. Two different types of hot filament arrangements are respectively adopted for depositing diamond films on the interior surface of valve seat and outer surface of valve spool. The fabricated CVD diamond coated relief valve components are characterized using Scanning electron microscope (SEM), X-ray diffraction spectroscopy (XRD), and Raman spectroscopy. The results exhibit that working surfaces of both valve seat and spool are covered by a layer of continuous, homogeneous diamond films on which well-faceted diamond grains with grain size of ~2-3 μm distribute. Furthermore, the fabricated relief valve components are equipped on a coal liquefaction facility and their performance is evaluated in real production. The results present that the working lifetime is largely elongated up to ~1200 hours, as more than three times as that of conventional tungsten carbide valve components.

Selective Growth of B-Doped Diamond on Si-Doped Diamond Film

2012 ◽  
Vol 217-219 ◽  
pp. 1013-1017
Author(s):  
Y.X. Cui ◽  
B. Shen ◽  
F.H. Sun ◽  
Z.M. Zhang
Keyword(s):  
Diamond Film ◽  
Sacrificial Layer ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Selective Area ◽  
Si Doped ◽  
Cvd Diamond Film ◽  
Hot Filament ◽  
Area Deposition

Si doped CVD diamond films are prepared on Si substrate by means of hot filament chemical vapor deposition (HFCVD) through adding tetraethoxysilane (TEOS) into acetone as source of reactant gas during the growth process. The samples of diamond films are investigated by scanning electron micrograph (SEM), Raman spectrum, X-ray diffractometry (XRD) and surface profiler. The experimental results show that compared with pure diamond film, Si doped CVD diamond film exhibits grain refinement and smoother surface. Then selective area deposition (SAD) of B-doped diamond films are achieved on both Si doped CVD diamond film and pure CVD diamond film with silicon dioxide layer as sacrificial layer. SEM investigation demonstrates that the boundary of patterning on pure diamond film is rather fuzzy while on pure diamond film it is trim and distinct, which is mainly attributed to the relatively low surface roughness.

Tribological Properties of CVD Diamond Films against Graphite

2016 ◽  
Vol 689 ◽  
pp. 86-90
Author(s):  
Xue Cai Lei ◽  
Ke Pang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Raman Spectroscopy ◽  
Vapor Deposition ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Frictional Coefficients ◽  
Hot Filament ◽  
Scanning Electron

In this investigation, micro crystalline diamond (MCD) and nanocrystalline diamond (NCD) films are deposited on cemented carbide (WC-Co) balls by hot filament chemical vapor deposition (HFCVD) technique. After deposition, MCD and NCD films are characterized by field emission scanning electron microscopy (FESEM) and Raman spectroscopy. Then frictional tests are carried out between CVD diamond coated balls and graphite. The results show that the MCD-graphite and NCD-graphite tribo-pairs exhibit comparable frictional coefficients, while the wear rate of graphite in MCD-graphite working pair is much higher than that of graphite in NCD-graphite working pair. Furthermore, the element oxygen is detected in the wear groove of graphite, suggesting the oxycarbide of working materials at the increased temperature due to the heat generated from the mechanical friction.

Surface Finishing of Electrically Conductive Diamond Tools by Electrolytic Machining

2012 ◽  
Vol 565 ◽  
pp. 400-405 ◽  
Author(s):  
Manabu Iwai ◽  
Kiyoshi Suzuki
Keyword(s):  
Complex Shape ◽  
Cvd Diamond ◽  
The Other ◽  
Surface Finishing ◽  
General View ◽  
Workpiece Material ◽  
Electrically Conductive ◽  
Long Period ◽  
Electro Discharge Machining ◽  
Coated Tool

This paper deals with a new surface finishing method of electrically conductive diamond materials by making efficient use of an electrically conductive nature of the workpiece material, instead of conventional methods such as grinding, lapping and polishing using diamond abrasives. The authors focused on the electrolytic machining method and not on the electro discharge machining method for the two advantageous features of the electrolytic machining in addition to the general view that a better surface roughness could be obtained. One of those features is that no higher heat is generated at the machining point. This can eliminate a risk of the film delamination in the case where a workpiece is the CVD diamond coated tool. The other is that a wider machining gap is available between an electrode and a workpiece. This was thought to allow the electrolytic machining to be applied to a tool with a complex shape such as a drill and an endmill. Based on these concepts, electrolytic machining experiments were conducted on the electrically conductive diamond materials. From the results, it was found that the surface of the electrically conductive diamond could be smoothened enough by electrolytic machining though relatively long period of time was required.

scholarly journals Development of High-Performance Polycrystalline CVD Diamond-Coated Cutting Tools Using Femtosecond Lasers

2021 ◽  
Vol 15 (4) ◽  
pp. 413-421
Author(s):  
Xiaoxu Liu ◽  
◽  
Osamu Konda ◽  
Hiroko Furuhashi ◽  
Kohei Natsume ◽  
...  
Keyword(s):  
High Performance ◽  
Cutting Tools ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Laser Parameters ◽  
Shaping Process ◽  
Tool Edge ◽  
Coated Tool ◽  
Fs Laser ◽  
Diamond Peak

Pulse laser grinding (PLG), an edge-shaping process, was developed previously to implement high-performance cutting tools. In this study, two femtosecond (fs) lasers with wavelengths of 1045 nm and 257 nm were used to conduct PLG on chemical vapor deposited (CVD) diamond-coated tool edges, as the fs laser is reported to have less thermal impact and the potential to improve the material crystallinity. We investigated the effects of the laser parameters on the tool edge formation and microstructural changes. The results show that although the infrared fs laser could – compared to the conventional nanosecond (ns)-laser PLG – naturally suppress surface thermal damage, the roughness of the processed surface remained relatively high with an Rz of 0.21 μm. However, under the optimal laser parameters proposed in this paper, an ultraviolet fs-laser PLG was used to obtain a much smoother edge, reducing Rz to approximately 0.08 μm. Moreover, scanning electron microscopy images indicated that the longitudinal machining marks on the ns-laser-processed surface were significantly reduced, with virtually no attached debris on the surface. Furthermore, from the Raman spectra, a significant increase in the diamond peak intensity was observed, indicating that the crystallinity of the CVD diamond (CVDD) was improved following ultraviolet-fs-laser PLG. These results demonstrate that edge shaping and structural modification of polycrystalline CVDDs can be integrated into ultraviolet-fs-laser PLG.

Effect of Grain Size of CVD Diamond Film on Cutting Performance of Diamond Coated Micro Drills

2012 ◽  
Vol 723 ◽  
pp. 407-411 ◽  
Author(s):  
Xue Lin Lei ◽  
Liang Wang ◽  
Bin Shen ◽  
Fang Hong Sun ◽  
Ming Chen
Keyword(s):  
Vapor Deposition ◽  
Flank Wear ◽  
Electrical Discharge Machining ◽  
Wear Behavior ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Cutting Performance ◽  
Nano Crystalline ◽  
Cvd Diamond Film ◽  
Hot Filament

In this study, micro- crystalline diamond(MCD), fine grade diamond(FGD) and nano- crystalline diamond(NCD) thin films are successfully coated on WC-Co micro drills(φ=400µm) adopting hot filament chemical vapor deposition (HFCVD) technique. The microstructure and cutting performance of micro drills for applying to drill electrical discharge machining(EDM) graphite coated with MCD, FGD and NCD films are systematically investigated by means of field emission scanning electron microscope(FESEM) and Raman spectroscopy. After drilling of 1500 holes, wear behavior of these micro drills is analyzed by FESEM and NCD coated micro drills exhibit minimum flank wear compared with the other samples due to the relatively good wear resistance and friction properties of NCD films.

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