DEPOSITION DLC FILMS WITH INCLUSION OF SILVER ...
DEPOSITION DLC FILMS WITH INCLUSION OF SILVER NANOPARTICLES Santos, L.C.D.1 , Lucas, F.L.C.3 , Freitas, D.O.2 , Leite, P.M.S.C.M.3 , Pessoa, R.S.3 , Maciel, H.S.3,4 , Santos, L.V.3 , Gomes, U. U.1 1
Department of Materials Science and Engineering, Federal University of Rio Grande do Norte, Natal, RN, Brazil. 2 Department of Mechanical Engineering, Federal University of Rio Grande do Norte, Natal, RN, Brazil. 3 University of Paraiba Valley, UNIVAP/IP&D, São José dos Campos, SP, Brazil 4 Technological Institute of Aeronautics, ITA/LPP, São José dos Campos, SP, Brazil E-mail: [email protected] This paper deals with the study and development of a process for the deposition of DLC films with insertion of silver nanoparticles in their structure. Seeking homogeneity of silver in the DLC film a cathodic silver cage was used. In the discharge plasma in the presence of cathodic cage interaction of the species generated in the plasma occurs with the surface of the cage, producing an erosion. The incorporation of silver in the DLC films have multifunctional effects and improves the tribological and bactericidal properties compared to the pure DLC film. Keywords: DLC film, plasma, cathodic silver cage.
Introduction Diamond like carbon film (DLC) is a notorious lubricant for aerospace application due to low friction and to avoid cold welding between hinges in satellite devices. With silver nanoparticles this films are used in space device for corrosion protection as passivation of atomic oxygen. Studies show that deposition with cathodic cage provides more homogeneous films (Nagatsuka et al, 2010;. Alves et al, 2006.). Experimental part Diamond-like carbon (DLC) films with silver nanoparticles were grown using a System of Plasma-enhanced Chemical Vapor Deposition (PECVD) as show in Fig.1. The DLC coatings were grow on AISI 301 steel using methane as precursor gas and a cathodic silver cage Fig.2. The plasma was assisted by pulsed dc power supply. The interlayer between DLC and metallic substrate was produced using a mixture of Argonne and Hexamethyldisiloxane (HMDSO).
Fig. 1: System of Plasma-enhanced Chemical Vapor Deposition (PECVD)
Fig.2: Picture of the plasma and silver cage through the reactor window
Results and discussion The critical load studies was conducted to evaluate the critical load between DLC film and AISI substrate, under the action of an progressive force applied using a (Rockwell
C) spherical diamond tipped cone of 120° angle. The friction was analyzed through the diamond tip and DLC coating pair in 10mm of track Fig. 3(a). The load for scratching test was applied with progressive load from zero till 18N. A sensitive acoustic microphone was used to detect critical load sound Fig.3(b). The Raman spectra showed a standard DLC with D and G band as demonstrated in (J. Robertson at Material Science and Engineering (2002) Fig.4.
Banda D
1200
Banda G -1
-1
1560cm
1360cm
intensity u.a
900
600
300
0
900
1200
1500
1800
-1
Raman shift (cm )
3(a) Image from 10mm of Scratching test track, (b )Plot with friction coefficient (CoF); Normal Load (N) and Acoustic emission (AE), (c and d) EDX results in side and out side of the track, (e and f): SEM in side and out side the track and (g): Secondary Electron spectroscopy.
Fig.4: Raman spectra DLC-Ag
Conclusions Was possible to deposit DLC-Ag films using cathodic silver cage. The Silver was spread in DLC films after friction coefficient as show in a secondary electron spectroscopy results Fig. 3(g). Due to silver had been removed and spread in the track, the friction coefficient was kept around 0.08. The acoustic emission was kept around 0,64 volt and the track did presented critical load. References [1] ALVES JR., C., ARAÚJO, F. O., RIBEIRO, K. J. B., da COSTA, J. A. P., SOUSA R. R. M., SOUSA R. S. Use of cathodic cage in plasma nitriding. Surface and coatings Technology, v. 201, p. 2450-2454, 2006. [2] NAGATSUKA, K., NASHIMOTO, A., AKAMATSU, K. Surface hardening of duplex stainless steel by low temperature active screen plasma nitriding. Surface and Coatings Technology, v. 205, p. S295-S299, 2010. Acknowledgement: CAPES, CNPq and Fapesp.
Department of Materials Science and Engineering, Federal University of Rio Grande do Norte, Natal, RN, Brazil. 2 Department of Mechanical Engineering, Federal University of Rio Grande do Norte, Natal, RN, Brazil. 3 University of Paraiba Valley, UNIVAP/IP&D, São José dos Campos, SP, Brazil 4 Technological Institute of Aeronautics, ITA/LPP, São José dos Campos, SP, Brazil E-mail: [email protected] This paper deals with the study and development of a process for the deposition of DLC films with insertion of silver nanoparticles in their structure. Seeking homogeneity of silver in the DLC film a cathodic silver cage was used. In the discharge plasma in the presence of cathodic cage interaction of the species generated in the plasma occurs with the surface of the cage, producing an erosion. The incorporation of silver in the DLC films have multifunctional effects and improves the tribological and bactericidal properties compared to the pure DLC film. Keywords: DLC film, plasma, cathodic silver cage.
Introduction Diamond like carbon film (DLC) is a notorious lubricant for aerospace application due to low friction and to avoid cold welding between hinges in satellite devices. With silver nanoparticles this films are used in space device for corrosion protection as passivation of atomic oxygen. Studies show that deposition with cathodic cage provides more homogeneous films (Nagatsuka et al, 2010;. Alves et al, 2006.). Experimental part Diamond-like carbon (DLC) films with silver nanoparticles were grown using a System of Plasma-enhanced Chemical Vapor Deposition (PECVD) as show in Fig.1. The DLC coatings were grow on AISI 301 steel using methane as precursor gas and a cathodic silver cage Fig.2. The plasma was assisted by pulsed dc power supply. The interlayer between DLC and metallic substrate was produced using a mixture of Argonne and Hexamethyldisiloxane (HMDSO).
Fig. 1: System of Plasma-enhanced Chemical Vapor Deposition (PECVD)
Fig.2: Picture of the plasma and silver cage through the reactor window
Results and discussion The critical load studies was conducted to evaluate the critical load between DLC film and AISI substrate, under the action of an progressive force applied using a (Rockwell
C) spherical diamond tipped cone of 120° angle. The friction was analyzed through the diamond tip and DLC coating pair in 10mm of track Fig. 3(a). The load for scratching test was applied with progressive load from zero till 18N. A sensitive acoustic microphone was used to detect critical load sound Fig.3(b). The Raman spectra showed a standard DLC with D and G band as demonstrated in (J. Robertson at Material Science and Engineering (2002) Fig.4.
Banda D
1200
Banda G -1
-1
1560cm
1360cm
intensity u.a
900
600
300
0
900
1200
1500
1800
-1
Raman shift (cm )
3(a) Image from 10mm of Scratching test track, (b )Plot with friction coefficient (CoF); Normal Load (N) and Acoustic emission (AE), (c and d) EDX results in side and out side of the track, (e and f): SEM in side and out side the track and (g): Secondary Electron spectroscopy.
Fig.4: Raman spectra DLC-Ag
Conclusions Was possible to deposit DLC-Ag films using cathodic silver cage. The Silver was spread in DLC films after friction coefficient as show in a secondary electron spectroscopy results Fig. 3(g). Due to silver had been removed and spread in the track, the friction coefficient was kept around 0.08. The acoustic emission was kept around 0,64 volt and the track did presented critical load. References [1] ALVES JR., C., ARAÚJO, F. O., RIBEIRO, K. J. B., da COSTA, J. A. P., SOUSA R. R. M., SOUSA R. S. Use of cathodic cage in plasma nitriding. Surface and coatings Technology, v. 201, p. 2450-2454, 2006. [2] NAGATSUKA, K., NASHIMOTO, A., AKAMATSU, K. Surface hardening of duplex stainless steel by low temperature active screen plasma nitriding. Surface and Coatings Technology, v. 205, p. S295-S299, 2010. Acknowledgement: CAPES, CNPq and Fapesp.
