Quantitative evaluation of adhesion of diamond coatings

1999 ◽  
Vol 14 (3) ◽  
pp. 1142-1147 ◽  
Author(s):  
Qi Hua Fan ◽  
A. Fernandes ◽  
E. Pereira ◽  
J. Grácio
Keyword(s):  
Quantitative Evaluation ◽  
Indentation Load ◽  
Diamond Coating ◽  
Diamond Coatings ◽  
Coating Adhesion ◽  
Indentation Tests ◽  
Deformation Stress ◽  
Small Indentation

This paper presents a model to evaluate quantitatively the adhesion of diamond coating according to indentation tests. It is found that small indentation load causes round spallation of the coating, no matter what the shape of the indenter. An exponential sink-in deformation of the coating under the indentation is proposed [y = −a × exp(−bx)]. The deformation stress at the spallation edge is considered the coating adhesion. Using an experimentally observed relation of the indentation load versus the film spallation radius, we evaluate the adhesion of a diamond coating on copper to be about 1.921–1.956 GPa, which is in agreement with thermal quench results. The validity of this model is also verified by its self-consistence.

Density Measurement of Powder Metallurgy Compacts by Means of Small Indentation

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Fabrizio Quadrini ◽  
Erica Anna Squeo
Keyword(s):  
Powder Metallurgy ◽  
Density Measurement ◽  
Calibration Procedure ◽  
Indentation Load ◽  
Instrumented Indentation ◽  
Packing Pressure ◽  
Indentation Tests ◽  
Density Evaluation ◽  
Compaction Of Powders ◽  
Small Indentation

In this study, the density of powder metallurgy compacts was measured by means of small indentation. Zinc (Zn) and aluminum (Al) tablets were fabricated by cold compaction of powders: different tablet densities were obtained by changing the packing pressure. Instrumented indentation tests were carried out by means of flat cylindrical indenters having diameters of 1mm and 2mm. After a calibration procedure, the slope of the indentation curve or the indentation load can be used for the density evaluation.

Effects of Two-Step DC Electrochemical Pretreatment of Fine Grinding WC-Co Tool Surface on Morphology and Quality of Diamond Coatings

2011 ◽  
Vol 337 ◽  
pp. 59-62
Author(s):  
Xiang Hui Zhang ◽  
Ling Wang ◽  
Jian Ping Long
Keyword(s):  
Surface Morphology ◽  
Direct Current ◽  
Arc Discharge ◽  
Etching Time ◽  
Diamond Coating ◽  
Diamond Coatings ◽  
Fine Grinding ◽  
Electrolytic Etching ◽  
Electrochemical Pretreatment

In the present investigation, diamond coating was deposited on fine grinding cemented carbide substrate by direct current arc discharge chemical vapor deposition. The effect of electrolytic etching time in the two-step electrochemical pretreatment process (firstly using electrolytic etching, and then using acid etching) on morphology and quality of the diamond coating were systemically studied. The surface morphology feature and quality of diamond coatings were characterized by means of Scanning Electron Microscope (SEM), laser Raman spectrometer respectively. The results showed that the electrolytic etching duration has distinctly effect on the quality and crystal features such as morphology, crystal type and grain size of diamond coating. It showed that as electrolytic current is direct current 3A, electrolytic etching time altering from 0.5 min to 7.5min, the surface morphology of diamond films gradually transition from microcrystalline cubic-octahedron to cauliflower type nanocluster, and further increase the electrolytic etching time, will lead to several negative effects on the quality and nucleation of the coatings which is not only retard the diamond nucleation, but also promote the formation of graphite.

Influence of Technical Parameters on the Residual Stress in the Diamond Coating

2012 ◽  
Vol 426 ◽  
pp. 85-88
Author(s):  
Hong Xiang Wang ◽  
Dun Wen Zuo ◽  
Chun Xu ◽  
Chun Zhou
Keyword(s):  
Residual Stress ◽  
Substrate Temperature ◽  
Compressive Stress ◽  
Crystalline Silicon ◽  
Volume Ratio ◽  
Chemical Vapor ◽  
Chamber Pressure ◽  
Diamond Coating ◽  
Diamond Coatings ◽  
Technical Parameters

The diamond coatings were prepared by hot filament chemical vapor deposition(HFCVD) on the mono-crystalline silicon substrates. The influence of the technical parameters such as methane volume ratio, substrate temperature and reaction pressure on the residual stress in the diamond coating was studied. The results showed that the residual stress in the coating was compressive stress in the range of parameters studied, and too high or too low substrate temperature, chamber pressure and methane volume ratio would all increase the residual compressive stress. This relationship can be explained by the influence of amorphous carbon content, vacancy density and grain size on the residual stress.

INFLUENCE OF EMBEDDED TUNGSTEN PARTICLES ON MECHANICAL BEHAVIORS OF CVD DIAMOND COATING

2019 ◽  
Vol 27 (02) ◽  
pp. 1950097
Author(s):  
YAO WANG ◽  
PING HE ◽  
YINGCHAO CHEN ◽  
MUSEN LIU ◽  
CHENG LI ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Tungsten Carbide ◽  
Chemical Vapor ◽  
High Hardness ◽  
Sem Analysis ◽  
Diamond Coating ◽  
Indentation Tests ◽  
Doping Technique ◽  
Cvd Diamond Coating ◽  
Hot Filament

Diamond coating has gained intensive attraction in the tribological field due to its high hardness. However, its weak flexibility always gives rise to the fragile crack, which causes the delamination and peeling off from substrate. In this work, a novel deposition method combining the conventional hot filament chemical vapor deposition (HFCVD) and particles doping technique is proposed to balance the hardness and flexibility of diamond coating, by which the diamond coating with tungsten particles is deposited on the co-cemented tungsten carbide substrate. The as-deposited diamond coating is characterized by scanning electron microscopy (SEM) analysis, surface roughness and Raman spectrum. The indentation tests are conducted to evaluate the crack propagation of diamond coating. Tribological behavior is examined on a reciprocating ball-on-plate tribometer. The results indicate that tungsten carbide may be formed between tungsten particles and diamond coating. The W–WC–amorphous carbon–diamond structural coating can validly inhibit the crack propagation and decrease the friction coefficient. Hence, adding embedding particles into the diamond coating may provide a useful way in enhancing the mechanical properties of diamond coating.

CVD Coated Diamond Tools for the Machining of Lightweight Materials

2014 ◽  
Vol 907 ◽  
pp. 63-73 ◽  
Author(s):  
Eckart Uhlmann ◽  
Fiona Sammler
Keyword(s):  
Cvd Diamond ◽  
Diamond Coatings ◽  
Silicon Alloys ◽  
Diamond Tools ◽  
Coating Adhesion ◽  
The Past ◽  
Coated Tools ◽  
Residual Stress Analysis ◽  
Materials Used ◽  
The Impact

The economic machining of materials used in the automotive and aeronautical industries, such as aluminium silicon alloys is often not possible without the use of superhard tools. CVD diamond coated tools have demonstrated their suitability for these applications in the past, however, the insufficient coating adhesion and thus tool failure remains an issue to date. Within the work presented here, two cemented carbide types were studied as substrates for CVD diamond coatings. Milling and turning tests were undertaken in order to assess the coating adhesion of the diamond tools. Furthermore, residual stress analysis was undertaken with the aim of understanding the impact of the coating and substrate residual stresses on the tool’s process performance.

Effects of Various Seeding Methods on Multi-Layered Diamond Coatings Deposited via Hot Filament Chemical Vapor Deposition

2013 ◽  
Vol 845 ◽  
pp. 36-40
Author(s):  
Tze Mi Yong ◽  
Esah Hamzah
Keyword(s):  
Natural Diamond ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Columnar Structure ◽  
X Rays ◽  
Diamond Coating ◽  
Diamond Coatings ◽  
Good Adhesion ◽  
Hot Filament ◽  
Xrd Method

Multi-layer alternating nanocrystalline diamond (NCD) layer and polycrystalline diamond (PCD) layer was successfully deposited on pretreated tungsten carbide (WC) substrates with various seeding sizes (<0.1μm synthetic, <0.5μm synthetic, <0.25μm natural, <0.5μm natural, and <1μm natural) diamond with and without hammering by silicon carbide. X-rays penetrate through the coating to the substrate from XRD method was able to show strong peaks of diamond relative to WC despite the diamond film being 4μm thick only. It is found that substrates with no hammering produce stronger signals. The coating was cross sectioned and analysed using field emission scanning electron microscopy showing the multi-layer with NCD grains that has coalesced and columnar structure for PCD. None of the diamond coating delaminated during cross sectioning showing good adhesion. Raman was able to capture data from the 1-1.6μm thick NCD layer only while AFM measured the extreme low roughness of the NCD surface.

Study of diamond adhesion behavior on chromium and titanium for obtaining adherent diamond coatings on steel

2000 ◽  
Vol 15 (11) ◽  
pp. 2330-2335 ◽  
Author(s):  
Q. H. Fan ◽  
J. Grácio ◽  
E. Pereira ◽  
N. Ali ◽  
W. Ahmed
Keyword(s):  
Diamond Films ◽  
Film Stress ◽  
Diamond Coatings ◽  
Micro Raman Spectroscopy ◽  
The Poor ◽  
Adhesion Behavior ◽  
Indentation Tests ◽  
Pure Chromium ◽  
Film Form ◽  
Poor Adhesion

It is known that diamond films display poor adhesion on metals such as copper and steel. One solution to overcome the poor adhesion is to use interlayer materials. In this study we report results of an investigation of the adhesion behavior of diamond on pure chromium (Cr) and titanium (Ti) substrates. Cr and Ti are promising interlayer materials for adhering diamond to stainless steel. The coating adhesion was studied using indentation tests combined with acoustic emission signals during loading. It was found that a 105-N load indentation caused the film to delaminate from the Cr substrate, while the diamond film remained attached to the titanium even after the indentation at 180 N. Micro-Raman spectroscopy was used to monitor the film stress. The diamond films grown on Ti substrates were found to be less stressed than the films grown on Cr substrates. Therefore, Ti was used in thin-film form to obtain adherent diamond coatings on steel.

Determination of High-Temperature Creep Property of High-Cr Steel Based Upon Indentation Test

2015 ◽  
Author(s):  
Masayuki Arai ◽  
Takahiro Ishikawa ◽  
Yukio Takahashi ◽  
Tomohisa Kumagai
Keyword(s):  
High Temperature ◽  
Creep Property ◽  
Indentation Test ◽  
Indentation Load ◽  
High Temperature Creep ◽  
Element Analysis ◽  
Temperature Creep ◽  
Inner Pressure ◽  
Indentation Tests ◽  
Actual Response

In this paper, the procedure which can estimate creep exponent and coefficient in Norton’s law from the impression size rather than the penetration depth is discussed based upon a high-temperature creep indentation test. Firstly, an analytical solution related to the change in impression size with dwelling time at an indentation load is formulated by solving problem of infinite creeping media embedding spherical cavity subjected to an inner pressure which characterizes an indentation load. The applicability of the formula to elastic-plastic-creeping model resembling an actual response is checked by conducting non-linear finite-element analysis combined with contact option. Finally, creep indentation tests are conducted for a high-Cr ferritic heat-resisting steel. It is shown that the creep parameters at a lower stress level can be estimated at temperature 873K.

Deforamtion and Fracture Behavior of Zr-Based Bulk Amorphous Metal Under Quasi-Static Compression

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1311-1317
Author(s):  
Hyung Seop Shin ◽  
Dong Kyun Ko ◽  
Sang Yeob Oh
Keyword(s):  
Strain Rate ◽  
Uniaxial Compression ◽  
Fracture Strength ◽  
Shear Bands ◽  
Indentation Load ◽  
Amorphous Metal ◽  
Uniaxial Compression Test ◽  
Static Compression ◽  
Plastic Deformation Behavior ◽  
Indentation Tests

The deformation and fracture behaviors of a bulk amorphous metal, Zr-based one ( Zr 41.2 Ti 13.8 CU 12.5 Ni 10 Be 22.5: Vitreloy), were investigated over a strain rate range (7 × 10-4~4 s -1). The uniaxial compression test and the indentation test using 3mm-diameter WC balls were carried out under the quasi-static loading condition. As a test result, at the uniaxial compression state, the fracture strength of the material was ~1,700MPa and the elastic strain limit was about 2%. The fracture strength showed a strain rate independent behavior up to 4 s-1. Using indentation tests, the plastic deformation behavior of the Zr-based BAM up to a large strain value of 15% could be achieved, even though it was the deformation under locally constrained condition. The Meyer hardness of the Zr-based BAM measured by static indentation tests was about 5 GPa and it revealed negligible strain hardening behavior. At indented sites, the plastic indentation occurred forming a crater and well-developed multiple shear bands were generated around it along the direction of 45° when the indentation load exceeded 7kN. With increasing indentation load, shear bands became dense. The fracture surface of the specimen after uniaxial compressive tests showed vein-like pattern, typical morphology of many BAMs.

Statistical Analysis of Experimental Parameters in Continuous Indentation Tests Using Taguchi Method

2003 ◽  
Vol 125 (4) ◽  
pp. 406-411 ◽  
Author(s):  
Eun-chae Jeon ◽  
Joo-Seung Park ◽  
Dongil Kwon
Keyword(s):  
Taguchi Method ◽  
Tensile Properties ◽  
Indentation Depth ◽  
Signal To Noise Ratio ◽  
Indentation Test ◽  
Indentation Load ◽  
Optimum Parameters ◽  
Experimental Parameters ◽  
Indentation Tests ◽  
Continuous Indentation

The continuous indentation test, which applies an indentation load to a material and records the indentation depth, yields indentation tensile properties whose accuracy can vary depending on such experimental parameters as number of unloadings, unloading ratio, maximum depth ratio and indenter radius. The Taguchi method was used to quantify their effects and to determine their optimum values. Using signal-to-noise ratio calculated from the error in the indentation tensile properties, the criterions and the optimum values for the experimental parameters were presented. The indentation tensile properties evaluated with the optimum parameters were in better agreement with the tensile properties.

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