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.

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.

Implementation of CVD Diamond Growth Methods for Selective and Efficient Formation of Color-Centers in Diamond

2015 ◽  
Vol 1728 ◽  
Author(s):  
Stefano Gay ◽  
Giacomo Reina ◽  
Ilaria Cianchetta ◽  
Emanuela Tamburri ◽  
Mariglen Angjellari ◽  
...  
Keyword(s):  
Diamond Films ◽  
Cvd Diamond ◽  
Structural Features ◽  
Diamond Growth ◽  
Color Centers ◽  
Diamond Synthesis ◽  
Substrate Preparation ◽  
Photoluminescence Emission ◽  
Diamond Phase ◽  
Growth Methods

ABSTRACTWe report here on the chemical methodologies that are being settled in our labs for the insertion in diamond of foreign atoms and consequent creation of fluorescent defects. The inclusion of Si, Cr, Ge, able to produce color centers, is directly obtained during the process of diamond synthesis by means of a CVD technique. The deposition of the diamond films takes place on substrates of different nature, treated following procedures specifically settled to control the insertion of the different species. The photoluminescence emission from a series of diamond samples grown on different substrates (Si, Ge and Ti) has been investigated and is discussed with reference to the morphological/structural features of the diamond phase and to the experimental procedures adopted for substrate preparation.

Silicon Nitride Tools Coated With Tic Or Tin Composite Diamond Structures

1995 ◽  
Vol 415 ◽  
Author(s):  
W.D. Fan ◽  
K. Jagannadham ◽  
J. Narayan
Keyword(s):  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Diamond Coating ◽  
Diamond Coatings ◽  
Adhesion Properties ◽  
Tin Films ◽  
Composite Diamond ◽  
Diamond Paste

ABSTRACTComposite diamond coatings on Si3N4 substrates have been developed to minimize stresses/strains and improve wear and adhesion properties. The coatings consist of a first layer of discontinuous diamond crystallites which are anchored to the Si3N4 substrate by a second interposing layer of TiC or TiN film. A top third layer of continuous diamond film is grown epitaxially on the first layer. The diamond films and TiC or TiN films were deposited using hot filament chemical vapor deposition and laser physical vapor deposition, respectively. The TiC and TiN films were examined by X-ray diffraction. The diamond films were characterized by scanning electron microscopy and Raman spectroscopy. Adhesion of the diamond coatings was investigated using overlap polishing with diamond paste, wear against Al-12.5%Si alloy, and pull-test. The results show that after introducing an interposing layer of TiC or TiN, adhesion of diamond coatings on Si3N4 substrates is improved significantly. After polishing test against diamond paste for 4 hours, only 30% of diamond was retained with single diamond coating while 80% of diamond was found with TiN composite diamond coating. The mechanism of improvement of adhesion is discussed.

Laser Cladding of Vanadium Carbide Interlayer for CVD Diamond Growth on Steel Substrate

2021 ◽  
pp. 127387
Author(s):  
R.L. Martins ◽  
D.D. Damm ◽  
R.M. Volu ◽  
R.A. Pinheiro ◽  
F.M. Rosa ◽  
...  
Keyword(s):  
Laser Cladding ◽  
Vanadium Carbide ◽  
Steel Substrate ◽  
Cvd Diamond ◽  
Diamond Growth

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.

Simulation of Gas Flow Field in HFCVD System for CVD Diamond Growth

2010 ◽  
Vol 431-432 ◽  
pp. 21-24
Author(s):  
Huan Qing Lin ◽  
Wen Zhuang Lu ◽  
Dun Wen Zuo ◽  
Chun Yang ◽  
Feng Xu
Keyword(s):  
Flow Field ◽  
Gas Flow ◽  
Cutting Tool ◽  
Cvd Diamond ◽  
Diamond Growth ◽  
Substrate Holder ◽  
Diamond Coating ◽  
Simulation And Experiment ◽  
Cvd Diamond Coating ◽  
Gas Flow Field

The thermal blockage and thermal round flow in HFCVD system for CVD diamond growth will lead to un-stability of product quality. Finite element method has been used to simulate the gas flow field around the cutting tool substrate within a HFCVD diamond reactor. Experiments have been done to prove the simulation results. Excellent agreement between simulation and experiment was obtained by depositing of CVD diamond coated cutting tool. The thermal blockage and thermal round flow in HFCVD system decrease by using a hollow substrate holder. High quality CVD diamond coating can be obtained using a hollow substrate holder.

scholarly journals SUPPRESSION OF CVD DIAMOND GROWTH ON SIDE FACE OF SUBSTRATE IN PROCESS OF GAS-PHASE PRECIPITATION

2018 ◽  
Vol 59 (8) ◽  
pp. 64
Author(s):  
Dmitry V. Teteruk ◽  
Vitaly S. Bormashov ◽  
Sergey A. Tarelkin ◽  
Nikolay V. Kornilov ◽  
Nikolay V. Luparev ◽  
...  
Keyword(s):  
Gas Phase ◽  
Diamond Films ◽  
Cvd Diamond ◽  
Diamond Growth ◽  
Structural Quality ◽  
Phase Precipitation ◽  
Diamond Layer ◽  
Side Face

CVD diamond grows on the all surfaces of the substrate, including the side faces. However, the diamond layer on side faces may be undesirable. We proposed and developed the method to suppress the CVD diamond growth on the side faces using silicon wells. The optimal geometric dimensions of the wells were determined. The studies of the structural quality of the CVD diamond films were carried out.

Adhesion Evaluation of CVD Diamond Films and Metal Reinforced Composite Diamond Films

1995 ◽  
Vol 383 ◽  
Author(s):  
D. F. Bahr ◽  
J..C. Nelson ◽  
D. Zhuang ◽  
E. Pfender ◽  
J. Heberlein ◽  
...  
Keyword(s):  
Composite Films ◽  
Cutting Tools ◽  
Diamond Films ◽  
Composite Layer ◽  
Cvd Diamond ◽  
Single Step ◽  
Diamond Growth ◽  
Metal Binder ◽  
Tension And Compression ◽  
Bend Tests

ABSTRACTPoor adhesion of diamond films limits the use of CVD diamond films as coatings for cutting tools. The adhesion of these films is limited by stresses in the film caused by thermal expansion mismatch between the substrate and the film and by voids present at the interface due to the morphology of the crystal growth. A three step process of making diamond composite films has been developed, involving nucleation of individual diamonds on the substrate, electroplating a metal binder in the voids between the crystals, and lastly growing a complete film over the composite layer. The metal binder acts both to fill the voids at the interface and to absorb energy during fracture processes at the interface. Diamond growth was performed in a DC Triple Torch reactor using a mixture of methane and hydrogen with a molybdenum substrate. Measurements to determine the amount of improvement of the film adhesion have been performed. These tests include indentations using conventional hardness testing equipment and four point bend tests with the film in tension and compression. A correlation is shown between the plastic zone of the substrate and the area of the film which delaminated during indentation. Bend tests with the film in tension did not delaminate the film, instead the film underwent intergranular fracture. Bend tests in compression act similarly to pile up around an indentation, and cause film delamination. Residual stress measurements in the single step film show a compressive stress of 650 MPa.

Geometric Model of CVD Mono-Crystalline Diamond Growth

2015 ◽  
Vol 730 ◽  
pp. 160-163
Author(s):  
Li Zhu Zhang ◽  
Fu Zhong Wang ◽  
Guang Tian
Keyword(s):  
Surface Area ◽  
Growth Model ◽  
Geometric Model ◽  
Diamond Films ◽  
Cvd Diamond ◽  
Growth Strategy ◽  
Diamond Growth ◽  
Film Characteristics

In order to describe the morphology of diamond films, we have developed a geometrical growth model which takes into account the displacement of the observed faces [1].We will see how to establish the topologies that are potentially accessible to CVD diamond growth.Lastly, we will present results showing the influence of the occurrence of certain crystalline faces on the film characteristics. From these results, we will show how the growth model and to establish a growth strategy aimed at obtaining large usable surface area crystals.

predicting the permissible external loading that a diamond-coated cutting tool can withstand without premature de-bonding. 3.1.6. Wear mechanisms. The failure of CVD diamond-coated inserts during machining can be in the form of flaking (interfacial failure) or abrasive wear (gradual cohesive failure) [22]. Ideally, a test of superb adhesion is when the diamond coating fully deteriorates by wear rather than flaking. Flaking will occur primarily due to poor adhesion between the diamond coating and the carbide substrate [6]. Therefore, flaking is clearly undesirable because the benefit of using a diamond coating is lost, except for the chip breaking assistance of faceted diamond crystals at the rake surface [29, 75]. If the adhesion strength of the CVD diamond coating is sufficient to withstand the machining stresses, then the abrasive action between the workpiece material and the diamond coating becomes the primary failure mechanism. Unless the CVD diamond coating is polished, a two-step wear mechanism is ex­ pected to occur. The first step is caused by the initial high surface roughness of the CVD diamond coating in which crack initiation occurs at the surface. The mecha­ nism that describes such behavior was proposed by Gunnars and Alahelisten [56]. They described a three-zone wear model as shown in Fig. 6. In this model, the role of residual stresses becomes significant in controlling crack propagation from the surface to the interface that could lead to interface failure (flaking). As outlined earlier, the high total compressive residual stress present in CVD diamond coatings on carbide inserts was assumed to be biaxial and oriented parallel to the interface. Wear starts to occur at the surface, which, because of geometry, allows stress to relax. A crack is more likely to initiate at protruding grains in zone I and propa­ gate preferentially along the (111) easy cleavage planes of diamond. The geometry at deeper depths, however, prevents the compressive residual stress from relaxing. Therefore, as the crack propagates deeper in the coating, it encounters higher com­ pressive stresses that cause the cracks to redirect their paths deviating from cleavage planes to a direction parallel to the interface in region II. The high compressive stress now causes cracks to propagate fast parallel to the interface resulting in a smooth surface in region III. Due to the smoother surface, fewer asperities will be present and it becomes harder to nucleate cracks.

2014 ◽  
pp. 100-139
Keyword(s):  
Residual Stress ◽  
Compressive Residual Stress ◽  
High Surface ◽  
Cvd Diamond ◽  
External Loading ◽  
Diamond Coating ◽  
Diamond Coatings ◽  
Cohesive Failure ◽  
Workpiece Material ◽  
Cvd Diamond Coating
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