DLC DLC 2005 2005 Se Jun Park, Kwang-Ryeol Lee, Seung-Cheol Lee, Future Technology Research...
-
Upload
felicia-garrison -
Category
Documents
-
view
225 -
download
3
Transcript of DLC DLC 2005 2005 Se Jun Park, Kwang-Ryeol Lee, Seung-Cheol Lee, Future Technology Research...
상대재에 따른 상대재에 따른 DLC DLC 필름의 필름의 마찰마모특성의 습도 의존성마찰마모특성의 습도 의존성
2005 2005 춘계 학술대회춘계 학술대회
Se Jun Park, Kwang-Ryeol Lee, Seung-Cheol Lee,
Future Technology Research Division,
Korea Institute of Science and Technology
Tribological Properties of Hard Coating Films
DLC
WC
TiN
CrN
TiCN
Wear Rate Friction Coefficient
2.0 1.6 1.2 0.8 0.4 0.2 0.4 0.6 0.8 1.0Relative value
Dependence of Tribological Behavior of DLC Films on Humidity
R. Gilmore et al Surf. Coat. Technol. 133-134, (2000), 437
Previous Works about the Environmental Dependence
Y. Kokaku et al. J. Vac. Sci. Technol. A 7 (1989) 2311
High friction coefficient in humid environment An unstable oxide layer on DLC film surface
involved in humid environment
B. Marchon et al, IEEE Trans. Magn. 26 (1990) 2670
Surface smoothness of DLC film by chemisorbed oxygen
The increase of real contact area
C. Donnet et al., Tribo. Letters, 4 (1998) 259
Prevention of the growth of the carbonaceous transfer film by the water vapor
DLC
Counterface
Reaction with H2O
Transfer layer
FN
FF
Tribology Process of DLC Film in Humid Air
DLC
Reaction with H2O
Reaction with H2O
FN
FF
Tribology Process of DLC Film in Humid Air
Tribo-chemical reaction
Transfer layer Material transfer
Counterface
Friction Coefficient of DLC FilmFriction Coefficient of DLC Filmand Counterfaceand Counterface
RH : 0 %
DLC against steel ball
RH : 50 %
RH : 90 %
2 ㎛
2 ㎛
2 ㎛
+
• S. J. Park et al, Diam.Rel.Mater., 12 (2003) 1517• S. J. Park et al, Tribol. Intl., 37 (2004) 913
Friction Behavior of DLC Using Steel Friction Behavior of DLC Using Steel Ball with the Change of HumidityBall with the Change of Humidity
• RH : 0 %Low oxidational wear of ball
• RH : 90 %High oxidational wear of ball
Frictioncoefficient
RelativeHumidity
• Formation of Fe-rich debris (Degradation of lubricant properties of DLC film)• Increase of the debris size
Steel
DLC
C-O-Fe
Fe-oxide
C-OSteel
DLC
MotivationsMotivations
DLC
If the formation of Fe-rich debris is suppressed, what will happen?
Steel
DLC
Purposes of the Present WorkPurposes of the Present Work
To characterize the tribological behavior of DLC film with the humidity change in various tribo-system. DLC against steel ball DLC against DLC coated ball
To find the reason for the humidity dependence of frictional behavior of DLC film in the view point of tribo-chemical reaction.
Deposition ConditionDeposition Condition
•RF PACVD(13.56 MHz)
•Precursor Gas : C6H6
•Deposition Pressure : 1.33 Pa
•Bias Voltage : - 400 Vb
•Substrate : P-type (100) Si-wafer
•Film Thickness : 1 ㎛
•Residual Stress : 0.9 ± 0.02 GPa
•Hardness : 11 ± 0.5 GPa
Tribo-test ConditionTribo-test Condition
• Ball-on-disc type tribometer isolated by chamber
• Counterface : AISI 52100 steel ball
DLC coated steel ball
• Normal Load : 4 N
• Rotation Speed : 20 cm/s
• Temperature : Room temperature
• Test Environment:
Ambient atmosphere
(Relative humidity : 0 – 90 %)
Film
Hygrometer
NormalLoad
Loadcell
Humidity controller
Rotary Pump
Friction Coefficient of DLC film Friction Coefficient of DLC film with Humidity Changewith Humidity Change
Chemical Composition of Debris Chemical Composition of Debris with Humidity Changewith Humidity ChangeDLC against DLC coated ball
Friction Coefficient and Friction Coefficient and Chemical Composition of the Chemical Composition of the DebrisDebris
Morphology of Debris on Track Morphology of Debris on Track with Humidity Changewith Humidity Change
RH : 0 % RH : 50 % RH : 90 %
2 ㎛ 2 ㎛ 2 ㎛
DLC against DLC coated ball
Friction Coefficient and Friction Coefficient and Chemical Composition of the Chemical Composition of the DebrisDebris
Raman Spectra of Transfer Raman Spectra of Transfer LayerLayer
DLC Coated Ball Steel Ball
Friction Coefficient Vs. Relative Humidity
Structure of Transfer Layer and Structure of Transfer Layer and Friction coefficient of Si-DLC filmFriction coefficient of Si-DLC film
Raman spectra of transfer layer of Si-DLC
• S. J. Park et al, Tribol. Intl., 37 (2004) 913
Raman spectra of transfer layer of DLC
Schematic Diagram of Friction Schematic Diagram of Friction Behavior in Humid AirBehavior in Humid Air
Formation of large size of debris
Formation of Fe-rich debris Formation of graphitic transfer layer Incorporation of Fe itself
Absence of Fe in debris Formation of diamond-like structure
of transfer layer
DLC
DLC
Steel
Steel
DLC
DLC Coated Ball
Steel Ball
Which is the major Contribution Which is the major Contribution of Fe incorporation?of Fe incorporation?
Fe-rich debris Fe-rich debris
RH : 90 % RH : 0 %
Graphitic transfer layer that is sensitive to humidity Incorporated Fe in debris itself
Abrupt change of humidity
Steel Steel
Abrupt change
of humidity
during tribo-test
Incorporation of Fe in debris itself
The formation of the graphitic layer sensitive to humidity
Gradual change of friction coefficient
Abrupt change of friction coefficient
Friction Coefficient with Friction Coefficient with Humidity Change during Tribo-Humidity Change during Tribo-testtest
The effect of Fe in debris on the friction behavior The formation of the graphitic transfer layer highly
sensitive to humidity`
The immediate drop of the friction coefficient
RH : 90 % RH : 0 %
ConclusionsConclusions
Using steel balls, the tribological behavior of DLC film was highly affected by humidity.
• Incorporated Fe in debris by wear of the steel ball enhanced the formation of highly graphitic layer.
The graphitic transfer layer was strongly sensitive to the humidity.
• When a graphitic transfer layer was formed, the friction coefficient of DLC film increased in humid environment.
Counterface materials should be chosen carefully in order to control the tribological behavior of DLC films.