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Environmental Dependence onEnvironmental Dependence on Tribological Behavior of Diamond-like Carbon Films Tribological Behavior of Diamond-like Carbon Films
with Nano-undulated Surfacewith Nano-undulated Surface
Jin Woo Yi Jin Woo Yi a,ba,b, Se Jun Park , Se Jun Park aa, Kwang-Ryeol Lee , Kwang-Ryeol Lee aa, Seock-Sam Kim , Seock-Sam Kim bb
aa Korea Institute of Science and Technology, Seoul, Korea Korea Institute of Science and Technology, Seoul, Korea
bb Kyuongpook National University, Daegu, Korea Kyuongpook National University, Daegu, Korea
THE INTERNATIONAL CONFERENCE ON THE INTERNATIONAL CONFERENCE ON METALLURGICAL COATINGS AND THIN FILMSMETALLURGICAL COATINGS AND THIN FILMS
ICMCTF 2006ICMCTF 2006May 1-5, 2006.May 1-5, 2006.
Town and Country Hotel, San Diego, California, USATown and Country Hotel, San Diego, California, USA
22
Merit of Diamond-like CarbonMerit of Diamond-like Carbon
TiNTiN
WCWC
TiCNTiCN
CrNCrN
DLCDLC
2.0 1.6 1.2 0.8 0.4 0.2 0.4 0.6 0.8 1.0
TiNTiN
WCWC
TiCNTiCN
CrNCrN
DLCDLC
2.0 1.6 1.2 0.8 0.4 0.2 0.4 0.6 0.8 1.0
Wear RateWear Rate Friction CoefficientFriction Coefficient
33
Demerit of Diamond-like CarbonDemerit of Diamond-like Carbon
• The frictional behaviors of DLC film largely depends on The frictional behaviors of DLC film largely depends on environmentalenvironmental conditions such as conditions such as relative humidityrelative humidity..
A.Gilmore et al., Surf. Coat. Technol., 133-134 (2000) 437A.Gilmore et al., Surf. Coat. Technol., 133-134 (2000) 437
44
Humidity Dependence Humidity Dependence of Frictional Behavior of DLC filmof Frictional Behavior of DLC film
S.J.Park et al., Diamond Relat. Mater. 12 (2003) 1517S.J.Park et al., Diamond Relat. Mater. 12 (2003) 1517
Relative Relative humidityhumidity
Friction Friction coefficientcoefficient
• Formation of Fe-rich debrisFormation of Fe-rich debris (Degradation of lubricant properties of DLC film)(Degradation of lubricant properties of DLC film)
• Increase of the debris sizeIncrease of the debris size
55
Possibility of Nano-undulated Surfaced DLC filmPossibility of Nano-undulated Surfaced DLC film
• DLC film with nano-undulated surface could suppress the DLC film with nano-undulated surface could suppress the dependence of environmental conditions.dependence of environmental conditions.
S.J. Park et al., Diamond Relat. Mater., 14 (2005) 1291-1296S.J. Park et al., Diamond Relat. Mater., 14 (2005) 1291-1296
66
Purpose of This WorkPurpose of This Work
• Tribological behavior of nano-undulated DLC film surface Tribological behavior of nano-undulated DLC film surface with various surface roughness in with various surface roughness in different humid different humid environmentsenvironments..
• Investigating the relationship between the Investigating the relationship between the surface roughness surface roughness and theand the humidity dependence on frictional behavior humidity dependence on frictional behavior of DLC of DLC filmsfilms
77
Fabrication of Fabrication of DLC Film with Nano-undulated SurfaceDLC Film with Nano-undulated Surface
AnnealingAnnealingNi-thin FilmNi-thin Film
•DC magnetron sputter• Deposition Pressure : 1.33 Pa• Current : 200 mA• Voltage : -430 V• Film Thickness : 3 ~ 9 nm
DLC film with DLC film with undulated surfaceundulated surface
•RF PACVD (13.56MHz)• Precursor Gas : CH4
• Deposition Pressure : 1.33 Pa• Bias Voltage : -150 Vb
• Film Thickness : 100±10 nm
DLC DepositionDLC Deposition
88
0 2 4 6 8 10
0
2
4
6
8
10
12
14
R
MS
Rou
ghn
ess
(nm
)
Thickness of Ni Film (nm)
Surface Roughness of DLC FilmsSurface Roughness of DLC Films
RRMS=9.4 nmRRMS=9.4 nm
RMS=8.1 nmRMS=8.1 nm
RMS=0.1 nmRMS=0.1 nm
RRMS=11.8 nmRRMS=11.8 nm
99
Raman SpectraRaman Spectra
800 1000 1200 1400 1600 1800 2000800 1000 1200 1400 1600 1800 2000800 1000 1200 1400 1600 1800 2000800 1000 1200 1400 1600 1800 2000
Inte
nsit
y (a
.u.)
Raman Shift (cm-1)
RMS 0.1 nm
Inte
nsit
y (a
.u.)
Raman Shift (cm-1)
RMS 8.1 nm
Inte
nsit
y (a
.u.)
Raman Shift (cm-1)
RMS 9.4 nm
Inte
nsit
y (a
.u.)
Raman Shift (cm-1)
RMS 11.8 nm
0 2 4 6 8 10 121480
1490
1500
1510
1520
1530
1540
G-p
eak
Posit
ion
(cm
-1)
Surface Roughness (nm)
1010
Environmental Tribo-meterEnvironmental Tribo-meter
•Wear-test conditionWear-test condition– Counter-ball : Steel bearing ball
(Dia. 6 mm)
(AISI 52100)
– Normal load : 200 gf (2 N)
– Sliding speed : 11.5 cm/sec
– Relative Humidity : 0 ~ 90 %
– @ room temperature
– Running Time : 10,000 cycles
WeightWeight
Load CellLoad Cell
Counter-Counter-ball Holderball Holder
FilmFilm
RotationRotation
Humid Controller
Rotary Pump
1111
Frictional BehaviorFrictional Behavior
0 2,000 4,000 6,000 8,000 10,0000.0
0.2
0.4
0.6
0 2,000 4,000 6,000 8,000 10,0000.0
0.2
0.4
0.6
0 2,000 4,000 6,000 8,000 10,0000.0
0.2
0.4
0.6
Fri
ctio
n C
oeff
icie
nt
Cycles
RH 0 %
Fri
ctio
n C
oeff
icie
nt
Cycles
RH 50 %
Fri
ctio
n C
oeff
icie
nt
Cycles
RH 90 %
RMS 0.1 nm
0 2,000 4,000 6,000 8,000 10,0000.0
0.2
0.4
0.6
0 2,000 4,000 6,000 8,000 10,0000.0
0.2
0.4
0.6
0 2,000 4,000 6,000 8,000 10,0000.0
0.2
0.4
0.6
0 2,000 4,000 6,000 8,000 10,0000.0
0.2
0.4
0.6
Fri
ctio
n C
oeff
icie
nt
Cycles
RH 0 %RMS 8.1 nm
Fri
ctio
n C
oeff
icie
nt
Cycles
RH 50 %
Fri
ctio
n C
oeff
icie
nt
Cycles
RH 90 %
Fri
ctio
n C
oeff
icie
nt
Cycles
0 2,000 4,000 6,000 8,000 10,0000.0
0.2
0.4
0.6
0 2,000 4,000 6,000 8,000 10,0000.0
0.2
0.4
0.6
0 2,000 4,000 6,000 8,000 10,0000.0
0.2
0.4
0.6
Fri
ctio
n C
oeff
icie
nt
Cycles
RH 50 %
RMS 9.4 nm
Fri
ctio
n C
oeff
icie
nt
Cycles
RH 0 %
Fri
ctio
n C
oeff
icie
nt
Cycles
RH 90 %
0 2,000 4,000 6,000 8,000 10,0000.0
0.2
0.4
0.6
0 2,000 4,000 6,000 8,000 10,0000.0
0.2
0.4
0.6
0 2,000 4,000 6,000 8,000 10,0000.0
0.2
0.4
0.6
0 2,000 4,000 6,000 8,000 10,0000.0
0.2
0.4
0.6
0 2,000 4,000 6,000 8,000 10,0000.0
0.2
0.4
0.6
Fri
ctio
n C
oeff
icie
nt
Cycles
R.H. 50 %
RMS 11.8 nm
Fri
ctio
n C
oeff
icie
nt
Cycles
R.H. 0 %
Fri
ctio
n C
oeff
icie
nt
Cycles
R.H. 90 %
Fri
ctio
n C
oeff
icie
nt
Cycles
Fri
ctio
n C
oeff
icie
nt
Cycles
1212
Mean Friction CoefficientMean Friction Coefficient
0 2 4 6 8 10 120.0
0.1
0.2
0.3
0.4
RH 0 % RH 50 % RH 90 %
Ave
rage
Fri
ctio
n C
oeff
icie
nt
Surface Roughness, Rq (nm)
1313
0 500 1000 1500 2000
Si
FeO
RH 0%
RH 90%Inte
nsity
(a.u
.)
Kinetic Energy (eV)
RH 50%C
RMS 11.8 nm, After Cleaning
0 500 1000 1500 2000
SiFeO
RH 0%
RH 90%Inte
nsity
(a.u
.)
Kinetic Energy (eV)
RH 50%C
RMS 0.1 nm, After Cleaning
Auger Spectra of Wear DebrisAuger Spectra of Wear Debris
1414
500 1000 1500 2000
Inte
nsit
y (a
.u.)
Raman Shift (cm-1)
RMS 11.8 nm
RH 0 %
RH 50 %
RH 90 %
500 1000 1500 2000
Inte
nsit
y (a
.u.)
Raman Shift (cm-1)
RMS 0.1 nm
RH 0 %
RH 50 %
RH 90 %
Raman Spectra of Transfer LayerRaman Spectra of Transfer Layer
1515
Morphology of Transfer LayerMorphology of Transfer Layer
200μm
RH 0% RH 50% RH 90%
RH 0% RH 50% RH 90%
RMS 0.1 nmRMS 0.1 nm
RMS 11.8 nmRMS 11.8 nm
200μm 200μm
200μm 200μm 200μm
Fe-oxide Fe-oxide debrisdebris
• Diamond-likeDiamond-like• No Fe-oxideNo Fe-oxide
Wear ScarWear Scar
1616
In Relative Humidity 90 %In Relative Humidity 90 %
Transfer LayerTransfer LayerFe-oxide ParticleFe-oxide Particle
Fe-oxideFe-oxide
Transfer LayerTransfer LayerFe-oxide ParticleFe-oxide Particle
Fe-oxideFe-oxide
In case of DLC film In case of DLC film with smooth surfacewith smooth surface
In case of DLC film In case of DLC film with rough surfacewith rough surface
DiscussionDiscussion
1717
ConclusionsConclusions
Controlling the surface roughness of DLC film in nano-scale can Controlling the surface roughness of DLC film in nano-scale can suppress the environmental dependence on frictional behavior of suppress the environmental dependence on frictional behavior of DLC film.DLC film.
- In case of DLC film with smooth surface, the bond structure of transfer - In case of DLC film with smooth surface, the bond structure of transfer layer reveals graphitic materials and a lot of Fe-oxide is observed in layer reveals graphitic materials and a lot of Fe-oxide is observed in the transfer layer with increase of relative humidity.the transfer layer with increase of relative humidity.
- In case of DLC film with rough surface, the bond structure of transfer - In case of DLC film with rough surface, the bond structure of transfer layer reveals diamond-like materials and less Fe-oxide is observed in layer reveals diamond-like materials and less Fe-oxide is observed in the transfer layer.the transfer layer.
1818
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