J. S. Zabinski, M. S. Donley, S. V. Prasad, and N. T. Mcdevitt, Synthesis and characterization of tungsten disulphide films grown by pulsed-laser deposition, Journal of Materials Science, vol.36, issue.18
DOI : 10.1007/BF00356530

T. Spalvins, Coatings for wear and lubrication, Thin Solid Films, vol.53, issue.3, pp.285-300, 1978.
DOI : 10.1016/0040-6090(78)90222-5

S. V. Prasad, N. T. Mcdevitt, and J. S. Zabinski, Tribology of tungsten disulfide films in humid environments:, Wear, vol.230, issue.1, pp.24-34, 1999.
DOI : 10.1016/S0043-1648(99)00082-4

S. R. Cohen, L. Rapoport, E. A. Ponomarev, H. Cohen, T. Tsirlina et al., The tribological behavior of type II textured MX2 (M=Mo, W; X=S, Se) films, Thin Solid Films, vol.324, issue.1-2, pp.190-197, 1998.
DOI : 10.1016/S0040-6090(97)01218-2

R. Gilmore, M. A. Baker, P. N. Gibson, W. Gissler, M. Stoiber et al., Low-friction TiN-MoS 2 coatings produced by dc magnetron co-deposition, Surf. Coat. Technol, vol.108, pp.345-351, 1998.
DOI : 10.1016/s0257-8972(98)00602-1

J. Pai, A. V. Sankar, and . Kvit, Structure, morphology and chemical composition of sputter deposited nanostructured Cr-WS 2 solid lubricant coatings, Surf. Coat. Technol, vol.205, pp.565-574, 2010.

X. H. Zheng, J. P. Tu, D. M. Lai, S. M. Peng, B. Gu et al., Microstructure and tribological behavior of WS2?Ag composite films deposited by RF magnetron sputtering, Thin Solid Films, vol.516, issue.16, pp.5404-5408, 2008.
DOI : 10.1016/j.tsf.2007.07.102

Q. Wang, J. P. Tu, S. C. Zhang, D. M. Lai, S. M. Peng et al., Effect of Ag content on microstructure and tribological performance of WS2?Ag composite films, Surface and Coatings Technology, vol.201, issue.3-4, pp.1666-1670, 2006.
DOI : 10.1016/j.surfcoat.2006.02.039

S. Xu, X. Gao, M. Hu, D. Wang, D. Jiang et al., Microstructure evolution and enhanced tribological properties of Cu-doped WS 2 films, Tribol. Lett, pp.55-56, 2014.
DOI : 10.1007/s11249-014-0322-3

T. W. Scharf, A. Rajendran, R. Banerjee, and F. , Growth, structure and friction behavior of titanium doped tungsten disulphide (Ti-WS2) nanocomposite thin films, Thin Solid Films, vol.517, issue.19, pp.5666-5675, 2009.
DOI : 10.1016/j.tsf.2009.02.103

A. Nossa and A. Cavaleiro, Mechanical behaviour of W???S???N and W???S???C sputtered coatings deposited with a Ti interlayer, Surface and Coatings Technology, vol.163, issue.164, pp.163-164, 2003.
DOI : 10.1016/S0257-8972(02)00622-9

A. Nossa and A. Cavaleiro, The influence of the addition of C and N on the wear behaviour of W?S?C/N coatings, Surface and Coatings Technology, vol.142, issue.144, pp.142-144, 2001.
DOI : 10.1016/S0257-8972(01)01249-X

M. Evaristo, A. Nossa, and A. Cavaleiro, W?S?C sputtered films: Influence of the carbon alloying method on the mechanical properties, Surface and Coatings Technology, vol.200, issue.1-4, pp.1076-1079, 2005.
DOI : 10.1016/j.surfcoat.2005.02.039

T. Polcar, M. Evaristo, and A. Cavaleiro, Friction of Self-Lubricating W-S-C Sputtered Coatings Sliding Under Increasing Load, Plasma Processes and Polymers, vol.307, issue.119, pp.541-546, 2007.
DOI : 10.1080/05698198208983101

URL : http://estudogeral.sib.uc.pt/jspui/bitstream/10316/8168/1/obra.pdf

J. V. Pimentel, T. Polcar, M. Evaristo, and A. Cavaleiro, Examination of the tribolayer formation of a self-lubricant W???S???C sputtered coating, Tribology International, vol.47, pp.47-188, 2012.
DOI : 10.1016/j.triboint.2011.10.021

S. Watanable, J. Noshiro, and S. Miyake, Tribological characteristics of WS2/MoS2 solid lubricating multilayer films, Surface and Coatings Technology, vol.183, issue.2-3, pp.347-351, 2004.
DOI : 10.1016/j.surfcoat.2003.09.063

S. Watanable, J. Noshiro, and S. Miyake, Friction properties of WS 2 /MoS 2 multilayer films under vacuum environment, Surf. Coat. Technol, pp.188-189, 2004.

L. N. Zhu, C. B. Wang, H. D. Wang, B. S. Xu, D. M. Zhuang et al., Microstructure and tribological properties of WS 2 /MoS 2 multilayer films, Appl. Surf. Sci, pp.258-1944, 2012.

D. C. Chen, B. L. Jiang, H. Y. Shi, and Y. N. Long, Effect of ion cleaning pretreatment on interface microstructure, adhesive strength and tribological properties of GLC coatings on Al substrates, Vacuum, vol.86, issue.10, pp.1576-1582, 2012.
DOI : 10.1016/j.vacuum.2012.03.034

T. Polcar, M. Evaristo, and A. Cavaleiro, The tribological behavior of W?S?C films in pin-on-disk testing at elevated temperature, Vacuum, vol.81, issue.11-12, pp.1439-1442, 2007.
DOI : 10.1016/j.vacuum.2007.04.010

J. R. Lince and P. D. Fleischauer, Crystallinity of rf-sputtered MoS 2 films, J. Mater
DOI : 10.1557/jmr.1987.0827

P. D. Fleischauer-]-f, J. A. Kerkhof, A. Moulijn, and . Heeres, Fundamental aspects of the electronic structure, materials [33 The XPS spectra of the metathesis catalyst tungsten oxide on silica gel, J. Electron Spectrosc. Relat. Phenom, pp.14-453, 1978.

V. R. Dhanak, A. Baraldi, G. Comelli, G. Paolucci, M. Kiskinova et al., CO adsorption on unreconstructed and reconstructed Rh (110) surfaces: LEED and XPS studies, Surf. Sci. Lett, pp.295-287, 1993.
DOI : 10.1016/0167-2584(93)91043-n

C. D. Wagner, D. A. Zatko, and R. H. Raymond, Use of the oxygen KLL Auger lines in identification of surface chemical states by electron spectroscopy for chemical analysis, Analytical Chemistry, vol.52, issue.9, pp.52-1445, 1980.
DOI : 10.1021/ac50059a017

L. Salvati, L. E. Makovsky, J. M. Stencel, F. R. Brown, and D. M. Hercules, Surface spectroscopic study of tungsten-alumina catalysts using x-ray photoelectron, ion scattering, and Raman spectroscopies, J. Phys. Chem, pp.85-3700, 1981.

. Levasseur, XPS analysis of oxido-reduction mechanisms during lithium intercalation in amorphous molybdenum oxysulfide thin films, Solid State Ionics, vol.76, pp.81-89, 1995.

D. Du, D. Liu, Z. Ye, X. Zhang, F. Li et al., Fretting wear and fretting fatigue behaviors of diamond-like carbon and graphite-like carbon films deposited on Ti-6Al-4V alloy, Applied Surface Science, vol.313, pp.313-462, 2014.
DOI : 10.1016/j.apsusc.2014.06.006

M. Huang, X. Zhang, P. Ke, and A. Wang, Graphite-like carbon films by high power impulse magnetron sputtering, Applied Surface Science, vol.283, pp.321-326, 2013.
DOI : 10.1016/j.apsusc.2013.06.109

G. Zhang, P. Yan, P. Wang, Y. Chen, and J. Zhang, The preparation and mechanical properities of Al-containing a-C:H thin films, J. Phys. D: Appl. Phys, pp.40-6748, 2007.

S. Xu, X. Gao, M. Hu, J. Sun, D. Wang et al., Morphology evolution of Ag alloyed WS 2 films and the significantiy enhanced mechanical and tribological properties, Surf. Coat. Technol, pp.238-197, 2014.

J. V. Pimentel, T. Polcar, M. Evaristo, and A. Cavaleiro, Examination of the tribolayer formation of a self-lubricant W?S?C sputtered coating, Tribology International, vol.47, pp.47-188, 2012.
DOI : 10.1016/j.triboint.2011.10.021

A. Katrib, F. Hemming, P. Wehrer, L. Hilaire, and G. Maire, The multi-surface structure and catalytic properties of partially reduced WO 3 , WO 2 and WC+O 2 or W+O 2 as characterized by XPS, J. Electron Spectrosc. Relat. Phenom, pp.76-195, 1995.

R. F. Bunshah, Handbook of Hard Coatings-Deposition Technologies, Properties and Applications, 2001.

J. C. Sanchez-lopez, D. Martinez-martinez, C. Lopez-cartes, and A. Fernandez, Tribological behaviour of titanium carbide/amorphous carbon nanocomposite coatings: From macro to the micro-scale, Surface and Coatings Technology, vol.202, issue.16, pp.202-4011, 2008.
DOI : 10.1016/j.surfcoat.2008.02.012

S. Miyake, Tribological properties of hard carbon films: extremely low friction mechanism of amorphous hydrogenated carbon films and amorphous hydrogenated SiC films in vacuum, Surf. Coat. Technol, vol.54, pp.563-569, 1992.

J. F. Archard, Contact and Rubbing of Flat Surfaces, Journal of Applied Physics, vol.10, issue.8, 1953.
DOI : 10.1063/1.1699869