A new design of tungsten carbide tools with diamond coatings

1996 ◽  
Vol 11 (9) ◽  
pp. 2220-2230 ◽  
Author(s):  
Volker Weihnacht ◽  
W.D. Fan ◽  
K. Jagannadham ◽  
J. Narayan ◽  
C-T. Liu
Keyword(s):  
Wear Resistance ◽  
Tungsten Carbide ◽  
Nickel Aluminide ◽  
Diamond Films ◽  
Diamond Growth ◽  
Nucleation Density ◽  
High Temperature Strength ◽  
Binder Phase ◽  
Chemical Vapor Deposition Diamond ◽  
Diamond Coatings

We have designed tungsten carbide tools with a new binder, which makes them suitable for advanced diamond tool coatings. The new tool substrates, made of tungsten carbide and nickel aluminide as binder phase, are produced by sintering and hot isostatic pressing, and also by combustion synthesis. The high temperature strength of nickel aluminide is key to superior tool performance at elevated temperatures. More importantly, nickel aluminides reduce the formation of graphite and promote diamond growth during chemical vapor deposition. Diamond films are deposited on the new tool substrates to investigate the nucleation density, adhesion, and wear resistance. The diamond coatings are characterized by scanning electron microscopy and Raman spectroscopy. The graphitizing tendency due to cobalt in the tungsten carbide tools was found to be a limitation to improve adhesion of diamond films. The new tool substrates with nickel aluminide binder have been found to exhibit good adhesion and wear resistance. The implications of these results in advanced cutting tools are discussed.

scholarly journals The Transformation from (111) to (100): A Routine to Large-Scale Epitaxial Diamond

2020 ◽  
Author(s):  
Yang Wang ◽  
Weihua Wang ◽  
Shilin Yang ◽  
Jiaqi Zhu
Keyword(s):  
Large Scale ◽  
Diamond Films ◽  
Diamond Growth ◽  
Nucleation Density ◽  
Diamond Synthesis ◽  
First Principle ◽  
High Quality ◽  
First Principle Calculations ◽  
Large Size ◽  
Experimental Researches

Diamond is a material with excellent performances which attracts the attention from researchers for decades. Pt (111), owing to its catalytic activity on diamond synthesis, is regarded to be a candidate for diamond hetero-epitaxity, which can enhance nucleation density. Molten surface at diamond growth temperature can also improve mobility and aggregation capability of primitive nuclei. Generally, (100)-oriented is welcomed for the achivement of high quality and large size diamond, since the formation of defects and twins are prevented. First-principle calculations and experimental researches were carried out for the study of transformation of orientation. The transformation from {111} to {100}-oriented diamond has been observed on Pt (111) substrate, which can be promoted by the increase of carbon source concentration and substrate temperature. The process is energetic favorable, which may provides a way towards large-scale (100) diamond films.

Adherent diamond coatings on cemented tungsten carbide substrates with new Fe/Ni/Co binder phase

2006 ◽  
Vol 494 (1-2) ◽  
pp. 133-140 ◽  
Author(s):  
Riccardo Polini ◽  
Michele Delogu ◽  
Giancarlo Marcheselli
Keyword(s):  
Tungsten Carbide ◽  
Binder Phase ◽  
Diamond Coatings ◽  
Cemented Tungsten Carbide

A sequential Raman analysis of the growth of diamond films on silicon substrates in a microwave plasma assisted chemical vapor deposition reactor

1997 ◽  
Vol 12 (10) ◽  
pp. 2686-2698 ◽  
Author(s):  
L. Fayette ◽  
B. Marcus ◽  
M. Mermoux ◽  
N. Rosman ◽  
L. Abello ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Sequential Analysis ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Diamond Growth ◽  
Internal Stresses ◽  
Nucleation Density ◽  
Silicon Substrates

A sequential analysis of the growth of diamond films on silicon substrates in a microwave plasma assisted chemical vapor deposition (CVD) reactor has been performed by Raman spectroscopy. The plasma was switched off during measurements, but the substrate heating was maintained to minimize thermoelastic stresses. The detectivity of the present experimental setup has been estimated to be about a few tens of μmg/cm2. From such a technique, one expects to analyze different aspects of diamond growth on a non-diamond substrate. The evolution of the signals arising from the substrate shows that the scratching treatment used to increase the nucleation density induces an amorphization of the silicon surface. This surface is annealed during the first step of deposition. The evolution of the line shape of the spectra indicates that the non-diamond phases are mainly located in the grain boundaries. The variation of the integrated intensity of the Raman signals has been interpreted using a simple absorption model. A special emphasis was given to the evolution of internal stresses during deposition. It was verified that compressive stresses were generated when coalescence of crystals took place.

Novel Nanocrystalline Composites

2002 ◽  
Author(s):  
J. Narayan
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Tungsten Carbide ◽  
Nickel Aluminide ◽  
Processing Technique ◽  
High Temperature Strength ◽  
Softening Behavior ◽  
Boundary Shear ◽  
Nanocrystalline Composites

We have developed a novel processing technique to fabricate tungsten carbide (WC) nanocomposites with uniform grain size. In this method, pulsed laser deposition of WC in conjunction with a few monolayers of nickel aluminide (NiAl) is used to control the grain size of nanocrystalline composites. The grain size of WC was controlled by the thickness of tungsten carbide and the substrate temperature. The role of NiAl is to ensure the nucleation of tungsten carbide islands, and it is relatively insoluble in WC. Using this approach, we have fabricated nanocomposites of grain sizes ranging from 6 nm to 35 nm. The hardness of the composite increases with the decrease in grain size, following approximately Hall-Petch relationship. Below a critical value, we observed a softening behavior which has been modeled to be related to intragrain deformation or grain boundary shear. The role of NiAl in grain boundary deformation is of particular interest in strengthening and stabilizing against the grain growth of nanocrystalline composites. The new WC-NiAl composite is expected to have superior high-temperature strength compared to conventional microcrystalline WC-Co composites.

Fracture of Thin Synthetic Diamond Films

1996 ◽  
Vol 436 ◽  
Author(s):  
M. D. Drory
Keyword(s):  
Synthetic Diamond ◽  
Steel Substrate ◽  
Diamond Films ◽  
Cvd Diamond ◽  
Diamond Growth ◽  
Steel Alloy ◽  
Diamond Coating ◽  
Diamond Coatings ◽  
Growth Environment ◽  
Substrate Hardness

AbstractLarge residual stresses in diamond coatings may result in film failure through splitting, delamination and substrate failure. In addition, the CVD diamond growth environment may degrade the substrate mechanical properties. These issues are examined for diamond-coating of a tool steel alloy. Diamond growth was achieved on the steel substrate with the use of a titanium interlayer. Embrittlement of the Ti interlayer was not evident, however the substrate hardness was severely degraded.

Mechanism of Diamond Growth on Carbide Substrates Using Fluorocarbon Gases

1993 ◽  
Vol 317 ◽  
Author(s):  
K.J. Grannen ◽  
R.P.H. Chang
Keyword(s):  
Silicon Carbide ◽  
Tungsten Carbide ◽  
Nucleation Rate ◽  
Growth Behavior ◽  
Selective Etching ◽  
Diamond Growth ◽  
Effect Of Temperature ◽  
Nucleation Density ◽  
Gas Mixture ◽  
Carbon Component

ABSTRACTThe etching and growth behavior of diamond in CxFy / O2 / H2 plasmas have been investigated. Using this gas Mixture, diamond can nucleate on untreated tungsten carbide and silicon carbide substrates up to a density of 108 crystallites/cm2. This compares to a density of 102 crystallites/cm2 when using a methane gas mixture and these same substrates. The increase in nucleation density is attributed to the selective etching of the non-carbon component of the carbide with subsequent nucleation on the carbon enriched surface. The effect of temperature on the nucleation rate has been studied with a lower nucleation density at higher growth temperatures.

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.

Selective Growth of Polycrystalline Diamond Thin Films

1992 ◽  
Vol 282 ◽  
Author(s):  
R. Ramesham
Keyword(s):  
Plasma Etching ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Polycrystalline Diamond ◽  
Selective Growth ◽  
Diamond Growth ◽  
Nucleation Density ◽  
Substrate Type ◽  
Temperature Growth ◽  
Single Crystal Diamond

ABSTRACTMicrowave plasma assisted CVD is employed to grow diamond films using a gas mixture of H2 and CH4on various substrates. Diamond has a tendency not to nucleate growth on mirror-smooth finished substrates irrespective of the substrate type (except single crystal diamond). We have developed various processes to enhance the nucleation density of the diamond substantially by damaging or seeding the surface of the substrates. Several process techniques such as 1. silicon nitride and silicon dioxide process, 2. ultrasonic agitation process, 3. selective seeding of diamond by electroplating of Cu, 4. patterning of diamond films by air-microwave plasma etching, etc., were developed to achieve the patterns of diamond on various substrates. Selective growth of doped diamond and low temperature growth of diamond for microelectronic applications have also been achieved by using the above processes (1 and 2). Details on selective diamond growth processes and the morphology of as-deposited selective diamond by SEM are presented.

Effect of Surface Treatments on the Structural and Mechanical Properties of Nanostructured Diamond Coatings on Tungsten Carbide Cutting Tools

2003 ◽  
Vol 791 ◽  
Author(s):  
Vaibhav Vohra ◽  
Shane A. Catledge ◽  
Yogesh K. Vohra
Keyword(s):  
Tungsten Carbide ◽  
Diamond Film ◽  
Interfacial Adhesion ◽  
Single Layer ◽  
Chemical Vapor ◽  
Film Structure ◽  
Nanocrystalline Diamond ◽  
Growth Surface ◽  
Binder Phase ◽  
Diamond Coatings

ABSTRACTChemical Vapor Deposition (CVD) using hydrogen, methane, and nitrogen feed gases has proven to be useful in depositing well-adhered diamond films on metal substrates. These films have already found a market in the cutting tool industry as coatings on cobalt-cemented tungsten carbide (WC-Co) inserts. The purpose of this investigation is to examine how the thermal and chemical pre-treatments typically used for carbide inserts (to remove the cobalt binder near the surface) affect the structure and interfacial adhesion of the diamond coating. Removal of the cobalt binder phase in various pre-treatment methods has been shown to minimize its catalytic effect of graphite formation during diamond deposition by CVD. The diamond-coated inserts in our study were characterized using x-ray diffraction, Raman spectroscopy, atomic force microscopy, and Rockwell indentation testing. We use an unconventionally high methane concentration in the feedgas in order to saturate the growth surface with carbon, thereby limiting cobalt migration from the bulk to the surface and reducing the dissolution and diffusion of carbon atoms coming from the plasma. Nitrogen is used in the feedgas in order to provide a tough, single-layer nanocrystalline diamond film structure. In addition, a multi-layer (nano-/micro-/nano-crystalline) CVD diamond film was grown by controlling the flow of nitrogen in order to show its characteristics in comparison with the single layer nanocrystalline diamond film. The multilayer film on the thermally-treated insert shows enhanced interfacial adhesion and fracture toughness when compared to other pretreatments and diamond coatings. This was demonstrated by indentation tests using 1470 N load.

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