Growth Time Optimization of Fine Grained Diamond Coated Drills for Machining CFRP

2016 ◽  
Vol 836-837 ◽  
pp. 333-339 ◽  
Author(s):  
Xin Chang Wang ◽  
Xiao Tian Shen ◽  
Tian Qi Zhao ◽  
Fang Hong Sun ◽  
Bin Shen
Keyword(s):  
Residual Stress ◽  
Protective Coatings ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Cutting Edge ◽  
Growth Time ◽  
Protective Effects ◽  
Initial Shape ◽  
Fine Grained ◽  
Film Substrate

Carbon fiber reinforced plastics (CFRP), which are widely used in the aerospace and some other new-tech industries, are considered very difficult to machine due to the material anisotropic and inhomogeneous features. Chemical vapor deposition (CVD) diamond films are suitable as protective coatings on cutting tools for machining advanced composite materials, owing to their extremely high hardness, favorable wear resistance, low friction coefficient and high thermal conductivity. Among different types of diamond films, the fine grained diamond (FGD) film can provide much more favorable environment for machining CFRP due to the small grain size, low surface roughness and the retentivity for the sharpness of the cutting edge. In the present study, aiming at drilling CFRP, FGD films of different thicknesses are deposited on Φ3 mm drills by controlling the growth time, adopting the common-used hot filament CVD (HFCVD) technology. It can be directly proved by deposition experiments that overlong growth time can induce spontaneous film delamination and removal before the cooling stage, probably as a result of the excessive residual stress concentrated on the complicated surfaces. As demonstrated by the cutting tests, with increasing the growth time, the main failure mode of the FGD coated drill changes from film delamination to flank wear/tipping to film delamination, and the maximum tool life exists when the growth time is moderate, because the flimsy film cannot provide sufficient protective effects on the film-substrate interface and even hasn’t totally cover the substrate, while there’s relatively higher residual stress in the film that is too thick, and such the residual stress can significantly deteriorate the film-substrate adhesion. Moreover, during the life cycle of each FGD film, relatively shorter growth time often means the slightly better hole quality, attributed to the retentivity of the initial shape of the uncoated drill that is optimal designed for machining CFRP, especially the weaker passivation of the cutting edge.

A study on the residual stress measurement methods on chemical vapor deposition diamond films

1998 ◽  
Vol 13 (11) ◽  
pp. 3027-3033 ◽  
Author(s):  
Jung Geun Kim ◽  
Jin Yu
Keyword(s):  
Residual Stress ◽  
Chemical Vapor Deposition ◽  
Tensile Stress ◽  
Residual Stresses ◽  
Vapor Deposition ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Peak Shift ◽  
Intrinsic Stress ◽  
Chemical Vapor Deposition Diamond

Diamond films were deposited on the p-type Si substrate with the hot filament chemical vapor deposition (HFCVD). Residual stresses in the films were measured in air by the laser curvature, the x-ray diffraction (XRD) dϕψ − sin2ψ, and the Raman peak shift methods. All of the measuring methods showed similar behaviors of residual stress that changed from a compressive to a tensile stress with increasing the film thickness. However, values of residual stresses obtained through the Raman and XRD methods were 3–4 times higher than those of the curvature method. These discrepancies involved the setting of materials constants of CVD diamond film, and determination of a peak shifting on the XRD and Raman method. In order to elucidate the disparity, we measured a Young's moduli of diamond films by using the sonic resonance method. In doing so, the Raman and XRD peak shift were calibrated by bending diamond/Si beams with diamond films by a known amount, with stress levels known a priori from the beam theory, and by monitoring the peak shifts simultaneously. Results of each measuring method showed well coincidental behaviors of residual stresses which have the stress range from −0.5 GPa to +0.7 GPa, and an intrinsic stress was caused about +0.7 GPa with tensile stress.

ENHANCEMENT OF ADHESION STRENGTH AND TRIBOLOGICAL PERFORMANCE OF CVD DIAMOND FILMS ON TUNGSTEN CARBIDE SUBSTRATES WITH HIGH COBALT CONTENT VIA AMORPHOUS SiC INTERLAYERS

2019 ◽  
Vol 26 (09) ◽  
pp. 1950051
Author(s):  
YUANPING HE ◽  
YU-XIAO CUI ◽  
FANG-HONG SUN
Keyword(s):  
Tungsten Carbide ◽  
Diamond Film ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Cobalt Content ◽  
Indentation Tests ◽  
Friction Performance ◽  
Film Substrate ◽  
Amorphous Sic ◽  
And Tungsten

In this study, the diamond films are deposited on tungsten carbide substrates with 10[Formula: see text]wt.% Co via hot filament chemical vapor deposition (HFCVD). Amorphous SiC (a-SiC) interlayers with various thicknesses are fabricated between the diamond films and tungsten carbide substrates via precursor pyrolysis to promote the adhesion and friction performance of diamond films. Indentation tests are performed to evaluate the adhesion of the as-fabricated diamond films, which show that the a-SiC interlayers can greatly improve the adhesive strength between diamond films and tungsten carbide substrates with 10[Formula: see text]wt.% Co. Moreover, the thickness of a-SiC interlayer is of great importance for the effectiveness on the film–substrate adhesion enhancement. The optimum thickness of a-SiC interlayer is 1[Formula: see text][Formula: see text]m. Afterwards, ball-on-disc experiments are chosen to check the tribological properties of the as-fabricated a-SiC interlayered diamond film specimen with the optimum interlayer thickness, which exhibits lower friction coefficient than the conventional diamond film with no interlayer.

Residual Stress Analysis of Microwave Plasma CVD Diamond Films

2005 ◽  
Vol 495-497 ◽  
pp. 1359-1364 ◽  
Author(s):  
Leng Chen ◽  
Wei Min Mao ◽  
Fan Xiu Lu ◽  
Ping Yang
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Thermal Stresses ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Orientation Distribution ◽  
X Ray ◽  
Plasma Chemical Vapor Deposition ◽  
Microwave Plasma Cvd

The residual stress and crystallographic texture of diamond films were investigated in the present work. The diamond films were synthesized on (100) silicon wafer by Microwave Plasma Chemical Vapor deposition (MPCVD). Then the residual stresses of the films were measured by X-ray diffractometer equipped with the two-dimensional detector. The residual stresses can be classified into two categories, i.e., the intrinsic stresses and the thermal stresses. It was shown that the thermal stresses were compressive in the temperature range studied and the intrinsic stresses were tensile. The crystallographic textures of the films were measured by X-ray diffractometer with the method of pole figure and orientation distribution function (ODF). The experimental results suggest that the crystallographic textures of the films depend upon the deposition temperature and methane flow rates, and the components and intensity of crystallographic textures have effect on the residual stresses in diamond films to a certain extent.

scholarly journals Temperature dependence of stress in CVD diamond films studied by Raman spectroscopy

2015 ◽  
Vol 33 (3) ◽  
pp. 620-626 ◽  
Author(s):  
Anna Dychalska ◽  
Kazimierz Fabisiak ◽  
Kazimierz Paprocki ◽  
Alina Dudkowiak ◽  
Mirosław Szybowicz
Keyword(s):  
Residual Stress ◽  
Thermal Stress ◽  
Temperature Dependence ◽  
Stress Component ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Cvd Diamond ◽  
Intrinsic Stress ◽  
Diamond Surface ◽  
Raman Shift

Abstract Evolution of residual stress and its components with increasing temperature in chemical vapor deposited (CVD) diamond films has a crucial impact on their high temperature applications. In this work we investigated temperature dependence of stress in CVD diamond film deposited on Si(100) substrate in the temperature range of 30 °C to 480 °C by Raman mapping measurement. Raman shift of the characteristic diamond band peaked at 1332 cm-1 was studied to evaluate the residual stress distribution at the diamond surface. A new approach was applied to calculate thermal stress evolution with increasing tempera­ture by using two commonly known equations. Comparison of the residts obtained from the two methods was presented. The intrinsic stress component was calculated from the difference between average values of residual and thermal stress and then its temperature dependence was discussed.

Uniform Deposition of Chemical Vapor Deposition Diamond Films on Slender Tungsten Wires

2016 ◽  
Vol 848 ◽  
pp. 618-623
Author(s):  
Xin Chang Wang ◽  
Xiao Tian Shen ◽  
Tian Qi Zhao ◽  
Fang Hong Sun ◽  
Bin Shen
Keyword(s):  
Chemical Vapor Deposition ◽  
Diamond Film ◽  
Vapor Deposition ◽  
High Surface ◽  
Diamond Films ◽  
Surface Hardness ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Diamond ◽  
Substrate Adhesion ◽  
Film Substrate

In the present study, high-quality chemical vapor deposition (CVD) micro-crystalline diamond (MCD) film was successfully deposited on the surface of the Φ0.5 mm×120 mm tungsten wire using a special designed graphitic jig for supporting the substrate and a two-step deposition procedure for guaranteeing the uniformity of as-deposited diamond film. It is proved that as-deposited film indeed presented much more uniform thickness than that obtained using a conventional jig described in the previous literature, and a very thick WC interlayer spontaneously formed between the substrate and the diamond film, which together with as-deposited MCD film have significant effects on mechanical properties of the wire. Generally speaking, the coated wire remains extremely high surface hardness of the MCD film and considerable toughness of the substrate, along with favorable film-substrate adhesion. It is recognized that these the coated tungsten wires have broad application prospects, but the technologies for depositing diamond films that are thick enough on even longer and thinner wires still need further investigation.

An Analytical Model for Intrinsic Residual Stress Effect on Out-of-Plane Deflection in Chemical-Vapor-Deposited Free-Standing Thick Film

2001 ◽  
Vol 695 ◽  
Author(s):  
Jeung-hyun Jeong ◽  
Young-Joon Baik ◽  
Dongil Kwon
Keyword(s):  
Residual Stress ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Intrinsic Stress ◽  
Stress Effect ◽  
Layer By Layer ◽  
Free Standing ◽  
Stress Variation ◽  
Layer Deposition ◽  
Out Of Plane

ABSTRACTThe effect of residual stress on the out-of-plane deflection in a free-standing thick diamond films was investigated theoretically and experimentally. The deflection is believed to be caused by the variation in residual stress with film thickness. Key idea of this study is that the stress variation may be produced by gradually increasing substrate deformation resulting from the layer-by-layer deposition of the film. The layer-by-layer deposition was modeled by using infinitesimal plate-bending theory, considering the two deformation modes of contraction or expansion and bending. To verify the suggested model, several hundred micron thick diamond films were fabricated on Si, Mo and W substrates of varying thicknesses by microwave plasma assisted chemical vapor deposition. The model's predictions on bowing, based on intrinsic stress value measured by the curvature method, were in good agreement with the experimentally measured curvature of the as-released films. Finally, it is concluded that the bowing of CVD thick films depends on the intrinsic stress variation of the film associated with gradual increase in substrate deformation.

Macroscopic residual stress in chemical-vapor-deposition free-standing diamond films by x-ray diffraction analyses

1999 ◽  
Vol 75 (13) ◽  
pp. 1881-1883 ◽  
Author(s):  
O. Durand ◽  
J. Olivier ◽  
R. Bisaro ◽  
P. Galtier ◽  
J. K. Krüger ◽  
...  
Keyword(s):  
Residual Stress ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Diamond Films ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Free Standing ◽  
X Ray
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