Characteristics of austenitic stainless steel nitrided in a hybrid glow discharge plasma

A nitriding process based on two distinct nitrogen glow discharge modes, with sample temperatures ranging from 380 °Cto480°C, was employed to treat the surface of austenitic stainless steel (SS 304). The temperature is controlled exclusively by switching the operation conditions of the discharges. First mode of operation is the conventional one, named cathodic, which runs at higher pressure values (1 mbar) in comparison to the second mode, named anodic, which runs at the pressure range of 10-3 -10-2 mbar. Cathodic mode is used to quickly heat the sample holder, by the high ion flux. On the other hand, in the anodic mode, due to the lower operation pressure, higher effective ion acceleration takes place, which allows deeper ion implantation into the sample surface. This hybrid process was thoroughly explored regarding the duty cycle and conditions of operation, to achieve optimal performance of the treatments, which led to the attainment of surface hardness for samples of AISI SS 304 as high as 20 GPa and improvements including higher elastic modulus and resistance against corrosion. Detailed comparison among samples treated by this process with others treated by conventional method was done using nanoindentation, Auger Electron Spectroscopy (AES) and corrosion resistance testing

On The Hardness Of A-c:h Films Prepared By Methane Plasma Decomposition

Hard, thick, and almost stress free a-C:H films prepared by methane plasma decomposition are reported. The films were prepared on the cathode electrode of a conventional r.f.-sputtering system in the - 100 to - 1200 bias voltage range. The properties of films were determined using optical transmission spectroscopy, Raman spectroscopy, hardness, and stress measurements. Films with high hardness (18 GPa) and very low stress (0.7 GPa) were obtained. It is proposed that the network rigidity of the films with low stress is mainly maintained by a matrix of dispersed sp2 sites, in addition to some contribution of the sp3 C-C sites. The stress versus bias voltage dependence supports the subimplantation model, indicating that it also explains the origin of stress in films prepared by r.f. plasma decomposition. © 1998 Elsevier Science S.A. All rights reserved.3321-2113117Franceschini, D.F., Achete, C.A., Freire F.L., Jr., (1992) Appl. Phys. Lett., 60, p. 3229Chhowalla, M., Yin, Y., Amaratunga, G.A.J., McKenzie, D.R., Frauenheim, Th., (1996) Appl. Phys. Lett., 69, p. 2344Stoney, G.G., (1909) Proc. R. Soc. London Ser. A, 82, p. 172Campbell, D.S., (1970) Handbook of Thin Film Technology, , L.I. Maissel, R. Glang (Eds.), McGraw-Hill, New YorkHoffman, R.W., (1966) Physics of Thin Films, , G. Hass, R.E. Thun (Eds.), Academic Press, New YorkJiang, X., Reichelt, K., Stritzker, B., (1989) J. Appl. Phys., 66 (12), p. 5805Weiler, M., Sattel, S., Jung, K., Ehrhardt, H., Veerasamy, V.S., Robertson, E.J., (1994) Appl. Phys. Lett., 64, p. 2797Davis, C.A., (1993) Thin Solid Films, 226, p. 30Fallon, P.J., Veerasamy, V.S., Davis, C.A., Robertson, J., Amaratunga, G.A.J., Milne, W.I., Koskinen, J., (1993) Phys. Rev. B, 48, p. 4777Roberson, J., (1992) Surf. Coat. Technol., 50, p. 185Robertson, J., (1992) Phys. Rev. Lett., 68, p. 220Walters, J.K., Honeybone, P., Huxley, D., Newport, R., Howells, W.S., (1994) Phys. Rev. B, 50, p. 831Honeybone, P.J.R., Newport, R.J., Walters, J.K., Howells, W.S., Tomkinson, J., (1994) Phys. Rev. B, 50, p. 839Stephan, U., Frauenheim, T., Blaudeck, P., Jungnickel, G., (1994) Phys. Rev. B, 49, p. 1489Frauenheim, T., Blaudeck, P., Stephan, U., Jungnickel, G., (1993) Phys. Rev. B, 48, p. 4823Robertson, J., (1996) J. Non-Cryst. Solids, 198-200, p. 614Robertson, J., (1995) Diamond Relat. Mater., 4, p. 29

Ion Irradiation Effects On A-c:h, A-c:n:h And A-c:f:h Films

Hydrogenated amorphous carbon (a-C:H) films as well as films with incorporated nitrogen (a-C:N:H) and fluorine (a-C:F:H) have been irradiated with 400 keV N+ at fluences ranging from 1014 to 3 × 1016 ions cm-2. The films were 200 nm thick deposited on Si and irradiated at RT. The loss of H, N and F as function of the irradiated fluences was monitored via nuclear reactions. The results show that: (i) the loss of H in all cases is well explained by the molecular recombination model; (ii) there is no loss of N and F as function of fluence for the a-C:N:H and a-C:F:H films. The evolution of the hardness and Young modulus for the three films reach the same values of ≈12 and 130 GPa, respectively, at maximum fluence. The intrinsic stress data show a change from a compressive stress to a relaxed structure after irradiations. The Raman data confirm the microstructural evolution of the samples into a structure containing a large number of disordered sp2-C clusters. © 2006 Elsevier B.V. All rights reserved.2491-2 SPEC. ISS.409413Robertson, J., (2001) Thin Solid Films, 383, p. 81Gunther, J., Reschke, J., (1993) Surf. Coat. Technol., 60, p. 531Tainen, V., (2001) Diamond Relat. Mater., 10, p. 153Robertson, J., (1986) Adv. Phys., 35, p. 317Robertson, J., (1991) Prog. Solid State Chem., 21, p. 199Franceschini, D.F., Achete, C.A., Freire Jr., F.L., (1992) Appl. Phys. Lett., 60, p. 3229Franceschini, D.F., Freire Jr., F.L., Silva, S.R.P., (1996) Appl. Phys. Lett., 68, p. 2645Metin, S., Kaufman, J.H., Saperstein, D.D., Scotch, J.C., Heyman, J., Haller, E.E., (1994) J. Mater. Res., 9, p. 396Sah, R.E., Dischler, B., Bubenzer, A., Koidl, P., (1985) Appl. Phys. Lett., 46, p. 739Prioli, R., Jacobsohn, L.G., Maia da Costa, M.E.H., Freire Jr., F.L., (2003) Tribol. Lett., 15, p. 177Oliver, W.C., Pharr, G.M., (1992) J. Mater. Res., 7, p. 1564Stoney, G.G., (1909) Proc. Roy. Soc. London Ser. A, 82, p. 172Freire Jr., F.L., (2002) J. Non-Cryst. Solids, 304, p. 251Jacobsohn, L.G., Franceschini, D.F., Maia da Costa, M.E.H., Freire Jr., F.L., (2000) J. Vac. Sci. Technol. A, 18, p. 2230Adel, M.E., Amir, O., Kalish, R., Feldman, L.C., (1989) J. Appl. Phys., 66, p. 3248Baptista, D.L., Zawislak, F.C., (2004) Diamond Relat. Mater., 13, p. 1791Baptista, D.L., Garcia, I.T.S., Zawislak, F.C., (2004) Nucl. Instr. and Meth. B, 219, p. 846Ferrari, A.C., Robertson, J., (2000) Phys. Rev. B, 61, p. 1045