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Volume 9, June 2016, Pages 1-17
Effect of CVD-diamond coatings on the tribological performance of cemented tungsten carbide substrates
Kaleem Ahmad Najara, Nazir Ahmad Sheikha, Sajad Dina, Mohammad Ashraf Shahb
a Department of Mechanical Engineering, National Institute of Technology Srinagar 190006, India
b Department of Physics, National Institute of Technology Srinagar 190006, India
Abstract
A comparison has been documented between nanocrystalline diamond (NCD) and microcrystalline diamond (MCD) coatings deposited on cemented tungsten carbide (WC-Co) substrates with architectures of WC-Co/NCD & WC-Co/MCD, using hot filament chemical vapor deposition (HFCVD) technique. In the present work, the frictional characteristics were studied using ball-on-disc type linear reciprocating micro-tribometer, under the application of 1–10N normal loads, when sliding against smooth alumina (Al2O3) ceramic ball for the total duration of 15min, under dry sliding conditions. Nanoindentation tests were also conducted using Berkovich nanoindenter for the purpose of measurement of hardness and elastic modulus values. The average coefficients of friction of MCD and NCD coatings decrease from 0.37 – 0.32 and 0.3 – 0.27 respectively, when the load is increased from 1–10N. However, for conventional WC-Co substrate the average coefficient of friction increases from 0.60–0.75, under the same input operating conditions. The wear tracks formed on the surfaces of CVD-diamond coatings and WC-Co substrate, after friction measurement were characterised using Raman spectroscopy and scanning electron microscopy (SEM) techniques. However, the compositional analysis for the formation of tribo-layer observed on the wear tracks of CVD-diamond coatings was confirmed using energy dispersive spectroscopy (EDS) technique. Therefore, maintaining an appropriate level of normal load and using appropriate type of diamond coating, friction may be kept to some lower value to improve mechanical processes.
Keywords
Hot filament CVD; Nanocrystalline; Microcrystalline; Coefficient of friction; Wear track; Tribo-layer
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References
Ali, M., and Ürgen, M., 2011. Surface morphology, growth rate and quality
of diamond films synthesized in hot filament CVD system under
various methane concentrations. Applied Surface Science, 257(20),
8420-8426.
Chandran, M., Kumaran, C.R., Gowthama, S., Shanmugam, P., Natarajan, R.,
Bhattacharya, S.S., and Rao, M.R., 2013. Chemical vapor deposition
of diamond coatings on tungsten carbide (WC–Co) riveting inserts.
International Journal of Refractory Metals and Hard Materials, 37,
117-120.
Dumpala, R., Chandran, M., Kumar, N., Dash, S., Ramamoorthy, B., and Rao,
M.R., 2013. Growth and characterization of integrated nano-and
microcrystalline dual layer composite diamond coatings on WC–Co
substrates. International Journal of Refractory Metals and Hard
Materials, 37, 127-133.
Dumpala, R., Kumar, N., Kumaran, C. R., Dash, S., Ramamoorthy, B., and
Rao, M.R., 2014. Adhesion characteristics of nano-and
micro-crystalline diamond coatings: Raman stress mapping of the
scratch tracks. Diamond and Related Materials, 44, 71-77.
Erdemir, A., Fenske, G.R., Krauss, A.R., Gruen, D.M., McCauley, T., and
Csencsits, R.T., 1999. Tribological properties of nanocrystalline
diamond films. Surface and Coatings Technology, 120, 565-572.
Everitt, N.M., Silva, R.F., Vieira, J., Rego, C.A., Henderson, C.R., and
May, P.W., 1995. Friction measurements on hot filament CVD diamond
films deposited on etched tungsten carbide surfaces. Diamond and
related materials, 4(5), 730-734.
Hase, A., and Mishina, H., 2009. Wear elements generated in the
elementary process of wear. Tribology International, 42(11-12),
1684-1690.
Haubner, R., and Lux, B., 1996. On the formation of diamond coatings on
WC/Co hard metal tools. International Journal of Refractory Metals
and Hard Materials, 14(1), 111-118.
Haubner, R., and Rudigier, M., 2013. Raman characterisation of diamond
coatings using different laser wavelengths. Physics Procedia, 46,
71-78.
Jin, Y., Kato, K., and Umehara, N., 1998. Tribological properties of
self-lubricating CMC/Al2O3 pairs at high
temperature in air. Tribology Letters, 4(3-4), 243-250.
Mishina, H., and Hase, A. (2013). Wear equation for adhesive wear
established through elementary process of wear. Wear, 308(1),
186-192.
Oliver, W.C., and Pharr, G.M., 1992. An improved technique for
determining hardness and elastic modulus using load and displacement
sensing indentation experiments. Journal of Materials Research,
7(6), 1564-1583.
Pfeiffer, R., Kuzmany, H., Knoll, P., Bokova, S., Salk, N., and Günther,
B., 2003. Evidence for trans-polyacetylene in nano-crystalline
diamond films. Diamond and Related Materials, 12(3-7), 268-271.
Schwarzbach, D., Haubner, R., and Lux, B., 1994. Internal stresses in CVD
diamond layers. Diamond and Related Materials, 3(4-6), 757-764.
Sein, H., Ahmed, W., Jackson, M., Woodwards, R., and Polini, R., 2004.
Performance and characterisation of CVD diamond coated, sintered
diamond and WC–Co cutting tools for dental and micromachining
applications. Thin Solid Films, 447, 455-461.
Shen, B., and Sun, F., 2009. Deposition and friction properties of
ultra-smooth composite diamond films on Co-cemented tungsten carbide
substrates. Diamond and Related Materials, 18(2-3), 238-243.
Sun, F.H., Zhang, Z.M., Chen, M., and Shen, H.S., 2003. Improvement of
adhesive strength and surface roughness of diamond films on
Co-cemented tungsten carbide tools. Diamond and Related Materials,
12(3-7), 711-718.
Sun, F., Ma, Y., Shen, B., Zhang, Z., and Chen, M., 2009. Fabrication and
application of nano–microcrystalline composite diamond films on the
interior hole surfaces of Co cemented tungsten carbide substrates.
Diamond and Related Materials, 18(2-3), 276-282.
Wiora, M., Brühne, K., Flöter, A., Gluche, P., Willey, T.M., Kucheyev,
S.O., Van Buurenc, A.W., Hamzac, A.V., Bienerc, J., and Fechta,
H.-J., 2009. Grain size dependent mechanical properties of
nanocrystalline diamond films grown by hot-filament CVD. Diamond and
Related Materials, 18(5-8), 927-930.