Diamond/Carbide Nano-Composite Gradient Films: a Route to solve the Adhesion Issues of Diamond Films

2005 ◽  
Vol 890 ◽  
Author(s):  
Thorsten Staedler ◽  
Srikanth Vadali ◽  
Xin Jiang

ABSTRACTDue to their outstanding mechanical properties diamond films are ideal candidates for many cutting and machining applications. However, industrial applications of these films are limited due to poor adhesion. Two main reasons causing this poor adhesion, which are based on the extrinsic physical and chemical properties of diamond, can be identified: High mechanical stresses induced by a difference of the thermal expansion coefficient between the diamond film and the substrate as well as a catalytic effect in case of metallic substrates containing iron-, cobalt- and nickel that, in combination with a methane atmosphere during deposition, leads to soot formation. One option to overcome these difficulties is to provide an interfacial layer that acts as adhesion layer as well as barrier layer to prevent the catalytic effect of the substrate elements. Even though some successful examples exist, this approach usually requires a time consuming and expensive multi-step process.In this paper, the synthesis of nanocrystalline diamond/carbide composite films with a compositional gradient will be reported. Focusing on the example of diamond/ß-SiC the possibility to create a gradient layer ranging from ß-SiC to diamond in a controlled manner will be shown. The films are prepared by a Microwave Assisted Plasma Chemical Vapour Deposition process (MWCVD) using H2, CH4 and Tetramethylsilane (TMS) as reactive gases. The structure, grain sizes, and volume fractions of the components of these composite films, which consist of a mixture of diamond and carbide phase, can be controlled by adjusting the concentrations of the reactive gases in the gas mixture. This strategy, which handles all depositions in one process step, should allow for an improved diamond film adhesion on tools. The preparation and characterization of the composite films with special emphasize on their mechanical and tribological properties will be discussed and a short outlook on other diamond/carbide systems will be given.

2015 ◽  
Vol 821-823 ◽  
pp. 982-985 ◽  
Author(s):  
Tibor Izak ◽  
Oleg Babchenko ◽  
Vít Jirásek ◽  
Gabriel Vanko ◽  
Marián Vojs ◽  
...  

In this study we present the diamond deposition on AlGaN/GaN substrates focusing on the quality of the diamond/GaN interface. The growth of diamond films was performed using microwave chemical vapour deposition system in different gas mixtures: standard CH4/H2(at low and high ratio of CH4to H2) and addition of CO2to CH4/H2gas chemistry. The diamond films were grown directly on GaN films either without or with thin interlayer. As interlayer, 100 nm thick Si3N4was used. Surprisingly, in the case of standard CH4/H2gas mixture, no diamond film was observed on the GaN with SiN interlayer, while adding of CO2resulted in diamond film formation of both samples with and without SiN interlayer. Moreover, adding of CO2led to higher growth rate. The morphology of diamond films and the quality of the diamond/GaN interface was investigated from the cross-section images by scanning electron microscopy and the chemical character (i.e. sp3versus sp2carbon bonds) was measured by Raman spectroscopy.


Author(s):  
Ying Yan ◽  
Xuelin Lei ◽  
Yun He

The effect of nanoscale surface texture on the frictional and wear performances of nanocrystalline diamond films under water-lubricating conditions were comparatively investigated using a reciprocating ball-on-flat tribometer. Although the untreated nanocrystalline diamond film shows a stable frictional state with an average friction coefficient of 0.26, the subsequent textured films show a beneficial effect on rapidly reducing the friction coefficient, which decreased to a stable value of 0.1. Furthermore, compared with the nanocrystalline diamond coating, the textured films showed a large decreasing rate of the corresponding ball wear rate from 4.16 × 10−3 to 1.15 × 10−3 mm3/N/m. This is due to the fact that the hydrodynamic fluid film composed of water and debris can provide a good lubrication environment, so the entire friction process has reached the state of fluid lubrication. Meanwhile, the surface texture can greatly improve the hydrophilicity of the diamond films, and as the texture density increases, the water contact angle decreases from 94.75° of the nanocrystalline diamond film to 78.5° of the textured films. The proper textured diamond film (NCD90) exhibits superior tribological properties among all tested diamond films, such as short run-in period, low coefficient of friction, and wear rate.


2011 ◽  
Vol 117-119 ◽  
pp. 1310-1314
Author(s):  
Xing Rui Li ◽  
Xin Wei Shi ◽  
Ning Yao ◽  
Xin Chang Wang

Nano-crystalline diamond (NCD) films with good adhesion were deposited on flexible copper substrate with Ni interlayer by Microwave Plasma Chemical Vapor Deposition (MPCVD). In this paper, two-stage method was used to improve the adhesion between the copper substrates and the diamond films. The effect of deposition time of the first stage on the morphology, crystal structure, non-diamond phase and adhesive properties of diamond films was investigated. The performance and structure of the diamond films were studied by Scanning Electron Microscope (SEM), Raman Spectroscopy (Raman) and X-Ray Diffraction (XRD). The results showed that the films were nano-crystalline diamond films positively. Impress method was used to examine the adhesion between diamond film and the substrate. When deposition time is 1.5h, the adhesion between diamond film and the copper substrate is better than the others. When it was 2.5h or longer, because the graphite layers existed as intermediate, the adherence between the diamond films and copper substrates was very poor. Therefore, the diamond films were easily peeled off from the substrates. Otherwise, the second stage called annealing process after the deposition played an important role to the adhesion. The films would be easily peeled off by curling without the annealing process.


1996 ◽  
Vol 11 (7) ◽  
pp. 1765-1775 ◽  
Author(s):  
James M. Olson ◽  
Michael J. Dawes

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.


RSC Advances ◽  
2016 ◽  
Vol 6 (90) ◽  
pp. 87607-87615 ◽  
Author(s):  
B. B. Wang ◽  
D. Gao ◽  
I. Levchenko ◽  
K. Ostrikov ◽  
M. Keidar ◽  
...  

A simple and efficient method for synthesizing complex graphene-inspired BNCO nanoflakes by plasma-enhanced hot filament chemical vapour deposition using B4C as a precursor and N2/H2 reactive gases is reported.


2001 ◽  
Vol 18 (2) ◽  
pp. 286-288 ◽  
Author(s):  
Zhang Yu-Feng ◽  
Zhang Fan ◽  
Gao Qiao-Jun ◽  
Yu Da-Peng ◽  
Peng Xiao-Fu ◽  
...  

2009 ◽  
Vol 1203 ◽  
Author(s):  
R. Vispute ◽  
Andrew Seiser ◽  
Geun Lee ◽  
Jaurette Dozier ◽  
Jeremy Feldman ◽  
...  

AbstractA compact and efficient hot filament chemical vapor deposition system has been designed for growing electronic-grade diamond and related materials. We report here the effect of substrate rotation on quality and uniformity of HFCVD diamond films on 2” wafers, using two to three filaments with power ranging from 500 to 600 Watt. Diamond films have been characterized using x-ray diffraction, Raman Spectroscopy, scanning electron microscopy and atomic force microscopy. Our results indicate that substrate rotation not only yields uniform films across the wafer, but crystallites grow larger than without sample rotation. Well-faceted microcrystals are observed for wafers rotated at 10 rpm. We also find that the Raman spectrum taken from various locations indicate no compositional variation in the diamond film and no significant Raman shift associated with intrinsic stresses. Results are discussed in the context of growth uniformity of diamond film to improve deposition efficiency for wafer-based electronic applications.


2017 ◽  
Vol 267 ◽  
pp. 185-189
Author(s):  
Andrei Bogatov ◽  
Vitali Podgursky

The nanocrystalline diamond films were deposited by microwave plasma enhanced chemical vapour deposition (PE-CVD) on Si (100) substrate. Reciprocating sliding tests were conducted using Si3N4 balls as a counter body. A method based on the construction of the Abbott curve representing the areas of pristine and worn surface in the wear scars was applied for estimation of the wear rate. The calculated wear rates were compared with the results obtained by profilometric measurements and direct measurement of the wear scars cross sections by scanning electron microscopy (SEM).


Sign in / Sign up

Export Citation Format

Share Document