Diamond-like Carbon (DLC) coatings have attracted significant attention due to their low friction coefficient, high degree of hardness, chemical inertness, and high wear resistance as well as and their many possible uses in metallurgical, aeronautical, and biomedical applications. However, DLC has low adhesion strength to metallic substrates. Carbonitriding was performed before DLC deposition to improve this adherence. Different concentration of nitrogen in the gas mixture was used during the carbonitriding of Ti6Al4V alloy. DLC films were subsequently grown from methane using plasma enhanced chemical vapor deposition. The samples were characterized with Raman scattering spectroscopy, nanoindentation, and tribological tests. Films from 80.0% N2 had the best friction coefficient (0.07) and a critical load of ~22 N. In the scratching test, these films had adhesive failure and they completely detached from the substrate only in the end of the tests. SEM images show carbonitring promoted a significant increase in the surface defects (homogeneously distributed) but without the presence of microcracks. EDX analysis indicated that nitrogen element was diffused throughout the thickness of the samples. Hydrogen and carbon atoms from carbonitriding formed a diffusion-barrier layer that can be used as the first step for DLC deposition. This carbonitriding can also provide a carbide layer, which serves as the precursor for the nucleation and growth of DLC films.
L. F. Bonetti, G. Capote, L. V. Santos, E. J. Corat and V. J. Trava-Airoldi, “Adhesion Studies of Diamond-Like Carbon Films Deposited on Ti6Al4V Substrate with A Silicon Interlayer,” Thin Solid Films, Vol. 515, No. 1, 2006, pp. 375-379. doi:10.1016/j.tsf.2005.12.154
A. Shirakura, M. Nakaya, Y. Koga, H. Kodama, T. Hasebe and T. Suzuki, “Diamond-Like Carbon Films for PET Bottles and Medical Applications,” Thin Solid Films, Vol. 494, No. 1-2, 2006, pp. 84-91.
C. Damasceno, S. S. Camargo Jr., F. L. Freire Jr. and R. Carius, “Deposition of Si-DLC Films with High Hardness, Low Stress and High Deposition Rates,” Surface and Coatings Technology, Vol. 133-134, 2000, pp. 133-134.
H. Mori and H. Tachikawa, “Increased Adhesion of Diamond-Like Carbon-Si Coatings and Its Tribological Pro- perties, Surface and Coatings Technology, Vol. 149, No. 2-3, 2002, pp. 224-229.
C. Dumkum, D. M. Grant and I. R. McColl, “A Multilayer Approach to High Adhesion of Diamond-Like Carbon Coatings on Titanium,” Diamond and Related Materials, Vol. 6, No. 5-7, 1997, pp. 802-806.
M. Stüber, S. Ulrich, H. Leiste, A. Kratzsch and H. Holleck, “Graded Layer Design for Stress Reduced and Strongly Adherent Superhard Amorphous Carbon Films,” Surface and Coatings Technology, Vol. 116-119, 1999, pp. 591-598. doi:10.1016/S0257-8972(99)00224-8
T. A. Friedmann, J. P. Sullivan, J. A. Knapp, D. R. Tallant, D. M. Follstaedt, D. I. Medlin and P. B. Mirkarimi, “Thick Stress-Free Amorphous-Tetrahedral Carbon Films with Hardness Near That of Diamond,” Applied Physics Letters, Vol. 71, No. 26, 1997, p. 3820.
B. Kleinsorge, A. Ilie, M. Chhowalla, W. Fukarek, W. I. Milne and J. Robertson, “Electrical and Optical Properties of Boronated Tetrahedrally Bonded Amoprphous Carbon (Ta-C:B),” Diamond and Related Materials, Vol. 7, No. 2-5, 1998, pp. 472-476.
M. Tsujikawa, D. Yoshida, N. Yamauchi, N. Ueda, T. Sone and S. Tanaka, “Surface Material Design of 316 Stainless Steel by Combination of Low Temperature of Carburizing and Nitriding,” Surface and Coatings Technology, Vol. 200, No. 1-4, 2005, pp. 507-511.
M. Tsujikawa, N. Yamauchi, N. Ueda, T. Sone and Y. Hirose, “Behavior of carbon in low temperature plasma nitriding layer of austenitic stainless steel,” Surface and Coatings Technology, Vol. 193, No. 1-3, 2005, pp. 309-313.
M. S. Jellesen, T. L. Christiansen, L. R. Hilbert and P. M?ller, “Erosion-Corrosion and Corrosion Properties of DLC Coated Low Temperature Gas-Nitrided Austenitic Stainless Steel,” Wear, Vol. 267, No. 9-10, 2009, pp. 1709-1714. doi:10.1016/j.wear.2009.06.038
X. M. Li and Y. Han, “Mechanical Properties of Ti (C0.7N0.3) Film Produced by Plasma Electrolytic Carbonitriding of Ti6Al4V Alloy,” Applied Surface Science, Vol. 254, No. 20, 2008, pp. 6350-6357.
X. Cai and H. Bangert, “Hardness Measurements of Thin Films-Determining the Critical Ratio of Deph to Thickness Using FEM,” Thin Solid Films, Vol. 264, No. 1, 1995, pp. 59-71. doi:10.1016/0040-6090(95)06569-5
M. Blees, G. Winkelman, R. Balkenende and J. M. J. den Toonder, “The Effect of Friction on Scratch Adhesion Testing: Application to a Sol-Gel Coating on Polypropylene,” Thin Solid Films, Vol. 359, No. 1, 2000, pp.1-13.
A. A. Voevodin, J. M. Schneider, C. Rebholz and A. Matthews, “Multilayer Composite Ceramicmetal-DLC Coatings for Sliding Wear Applications,” Tribology International, Vol. 29, No. 7, 1996, pp. 559-570.
V. J. Trava-Airoldi, G. Capote, L. F. Bonetti, J. Fernandes, E. Blando, R. Hübler, P. A. Radi, L. V. Santos and E. J. Corat, “Deposition of Hard and Adherent Diamond-Like Carbon Films Inside Steel Tubes Using a Pulsed-DC Discharge,” Journal of Nanoscience and Nanotechnology, Vol. 9, No. 6, 2009, pp. 3891-3897.
Y. Fu, B. Yan and N. L. Loh, “Effects of Pre-Treatments and Interlayers on the Nucleation and Growth of Diamond Coatings on Titanium Substrates,” Surface and Coatings Technology, Vo1. 130, No. 2-3, 2000, pp. 173-185.
Y. Q. Fu, B. B. Yan, N. L. Loh, C. Q. Sun and P. Hing, “Deposition of Diamond Coating on Pure Titanium Using Micro-Wave Plasma Assisted Chemical Vapor Deposition,” Journal of Materials Science, Vol. 34, No. 10, 1999, pp. 2269-2283. doi:10.1023/A:1004569406535
V. Fouquet, L. Pichon, A. Straboni and M. Drouet, “Nitridation of Ti6Al4V by PBII: Study of the Nitrogen Diffusion and of the Nitride Growth Mechanism,” Surface and Coatings Technology, Vol. 186, No. 1-2, 2004, pp. 34- 39.