wear resistant and low friction nanocomposite coatings dr tomasz suszko
DESCRIPTION
Wear resistant and low friction nanocomposite coatings Dr Tomasz Suszko. Lecture outline. Plasma sputtering – short description DC-, triode-, RF-, magnetron sputtering Nonreactive and reactive mode Low friction nanocomposite coatings - PowerPoint PPT PresentationTRANSCRIPT
Wear resistant and low frictionnanocomposite coatings
Dr Tomasz Suszko
2International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
• Plasma sputtering – short description• DC-, triode-, RF-, magnetron sputtering• Nonreactive and reactive mode
• Low friction nanocomposite coatings
• Chosen results: Mo2N/Cu nancristaline films– structure, mechanical and tribological properties
• Structure, hardness• Friction & wear mechanisms in temperature range
RT-400°C
Lecture outline
3International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
http://fusedweb.pppl.gov/CPEP
Plasma - the 4th
state of matter
4International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Fundamentals of plasma sputtering– DC sputtering (diode sputtering)
-+
Cathode
Anode+ substrate
Pressure~10 Panoble gas(e.g. Ar)
Voltage~1.5 kV
• Electron emission
• Sputtering
• Implantation
• Defects generation
• E-m radiation
Ionis
ati
on c
oeff
cient
Electron energy [eV]
10 100 10000.01
0.1
1
10
Disadvantages:
• Low ion current density (low sputtering rate)
• High working gas pressure resulting in scattering (low deposition rate)
• Dielectric materials can not be sputtered
• High voltage is needed
5International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
-+ 100 V
Target
0.5 kV-
+
Substrate Ionis
ati
on c
oeff
cient
Electron energy [eV]
10 100 10000.01
0.1
1
10
+Lower working gas pressure – 0.1 Pa (higher deposition rate)
+Higher ion current density (higher sputtering rate)
– Dielectric materials can not be sputtered
Fundamentals of plasma sputtering– triode sputtering
6International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Ionis
ati
on c
oeff
cient
Electron energy [eV]
10 100 10000.01
0.1
1
10
+Lower working gas pressure – 0.1 Pa (higher deposition rate)
+Higher ion current density (higher sputtering rate)
– Dielectric materials can not be sputtered
Fundamentals of plasma sputtering – microwave assisted sputtering
Target
0.5 kV–
+
Substrate
Microwave antenna
7International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Substrate
Fundamentals of plasma sputtering – RF sputtering
RF
MatchboxThe differce in:• mobility of
electrons and ions• areas of
electrodes
results in
negative target selfbias
thus,
dielectric materials can be sputtered
8International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
ca thode
vd
R L
ve
vR E B
Fundamentals of plasma sputtering – motion of the electron in electromagnetic
field
RL
ve cos
veve sin
ve c o s
ve c o s
ve
LLR
sin
eL m
eB
9International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
10
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
11
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
There is a possibility to control the substrate ion current and the energy of the ions as well
– unbalanced magnetron sputtering
Substrate
Fundamentals of plasma sputtering– magnetron sputtering
DC or pulsed power supply
Ion
isati
on
coeff
cien
t
Electron energy [eV]
10 100 10000.01
0.1
1
10
+ Low working gas pressure – 0.1 Pa
+ Very high ion current density is possible (high sputtering rate)
12
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
What materials can be sputtered and deposited?
Whatever one need?
It must be kept in mind that:
• Compounds, targets are made of, are decomposed to the atomic form and only then can react again on the substrate (not always getting appropriate conditions)
• Sputtered atoms are scattered along their way towards substrate (the lighter the more intense thus the stoichiometry can change)
• A sputtered compound can not to easily evaporate (sufficient vacuum can not be obtain)
13
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
End of part one
14
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
•Mean free path•Secondary electron emmision•Ion implantation •Sputtering•Charging effect •Thermoemission•Magnetic mirror and trap •Larmor frequency and radius•Magnetron source (gun)
From yesterday
15
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Fundamentals of plasma sputtering – reactive sputtering
Compounds of the target and gas elements For poorly conducting
or insulator deposits pulsed power supply is very usefull
Pumping system
Inert gas (e.g. Ar)Reactive gas (N2, O2, CH4 etc.)
Optical signal(optical emission spectroscopy)
• Gas pressure• Gas flows• Discharge power• (Substrate bias –
energy of the ions)• (Substrate ion
current density)
Control unit
16
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
What I won’t speak about is...
•Plasma enhanced chemical vapour deposition
•Laser ablation•Plasma spraying•Ion implantation (clasical orplasma immersion)
•Plasma nitriding orcarburazing
etc.
17
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Plasma maintained by:• DC or pulsed discharge
(magnetron),• Vacuum arc, RF e-m waves
Plasma maintained by:• DC or pulsed discharge
(magnetron),• Vacuum arc, RF e-m waves
Working gases:• Ar (inert gas),• N2 (for nitrides),• O2 (for oxides),• CH4, C2H2 (for carbides and
DLC)
Working gases:• Ar (inert gas),• N2 (for nitrides),• O2 (for oxides),• CH4, C2H2 (for carbides and
DLC)
Targets made of:• Ti, Al, Mo, V, Ag, Cubut also• Fe, Ni, Coand• Si
Targets made of:• Ti, Al, Mo, V, Ag, Cubut also• Fe, Ni, Coand• Si
What we use for deposition is...
18
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Coils supply
Pulsed powersupply
Substratebias
and heating
Pulsed powersupply
Spectrometer
Pumping system
Optical signal
GasesValve unit
Magnetron sources
What we develop for process control and data acquisition is...
19
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.orgF
L
What we interest in is...
Continuous looking for novel anti-wear coatings and development of their deposition methods
Phenomena in the tribolgical contact between hard coated surface and a counterpart
• Structure, elemental and phase composition of the coatings in the initial state (after deposition)
• Stress, adhesion, hardness of the coatings• Friction during tribological tests (especially in elevated
temperatures)• Tribomutation - chemical and physical changes of the „third
body” – elemental and phase composition, structure etc. of that
• The role of oxides in friction process
20
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Where can we look for hard compounds?
21
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Chemical sythesis ( DLC, c-BN, AlMgB, C3N4 )
Forming proper physical microstructure
• Nitride or carbide multilayers(TiN/CrN, TiN/TiAlN i in.)
• Compositesnc-MexN/a-Si3N4 nc-MexC/a-C:H np. nc-TiN/a-Si3N4
• Composites MexN/M np. (ZrN/Cu, Cr2N/Cu, TiN/Ag)
How to obtain hard films
22
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
L
A
L
F
Shear strength and hardness depend on each other thus friction coefficients are comparable for various izotropic materials.
Shear strength and hardness depend on each other thus friction coefficients are comparable for various izotropic materials.
Hardness is not all - there is friction also!
Shear strengthHardness
HAH
A
F
L
A AA
large small small large
Softmaterials
F
L
Hardmaterials
A
23
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
F
L
Self-lubricating materials
• As a result of rubbing, a thin low-shear--strengh layer should appear
• The material should be hard (what ensures small contact area)
Composite materials:
guaiac wood
PTFE impregnated bronzes
bearing metals with graphite or MoS2
inclusions
ceramic/carbon fiber composites
Izotropic materils:
diamond
24
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
RTDinfo - Mag. Europ. Res., 39, 2003
Self-lubricating FILMS
Hard coating
Enviromentalgas
Lubricating film
25
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Mo2N as a hard coating
MoO3 as a solid lubricant
Cu additive as a mean for hardness enhancement
An attempt - Mo2N/Cu coatings
26
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Mo2N/Cu nanocrystalline films – structure, mechanical
and tribological properties
Suszko et al., Surf. Coat. Tech., 200, 2006, pp. 6288-6292Suszko et al., Surf. Coat. Tech., 194, 2005, pp. 319-324
Outline
1. Deposition method2. Some remarks on the structure3. Hardness of the films4. Friction & wear in temperature range RT-400°C5. Conclusions
27
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Deposition method:unbalanced magnetron sputtering
pulsed powersupply
pulsed powersupply
sample
external coils
pumps
Ar, N2
Mo Cu
optical signal
30 cm
Temperature: 200 °CBias: -30 V
28
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Structure – XRD spectra
0
2
4
6
8
10
12
14
16
18
Inte
nsi
ty [
a.u
.]
Fe (substrate)
0% at. Cu
1% at. Cu
6% at. Cu9% at. Cu
21% at. Cu
40 45 50 55 60 65Diffraction angle 2ϑ [°]
← γ-Mo2N (111)
γ-Mo2N (200)→
← Cu (111)
Cu (200)→
Co Kα radiation
29
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Cu content (at. %)0 5 10 15 20 25
5
6
7
8
9
10
11
12
13
Cry
stalli
te s
ize [
nm
]
Mo2N (200)
Crystallite size obtained from Scherrer’s formula AFM image of the pure
γ–Mo2N nitride
The influence of copper content on crystalite size
cos
Kt
30
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
StructureCrystallite size and film hardness
Cu content (% at.)0 5 10 15 20 25
5
6
7
8
9
10
11
12
13
Cry
stalli
te s
ize (
nm
)
Mo2N (111)
Mo2N (200)
0 5 10 15 20 2510
15
20
25
30
35
40
Cu content (% at.)
H (
GPa)
Load-depthsensitive method
DUH 202 (FN 20 mN)
Load-depthsensitive methodHysitron (FN 2mN)
Traditional method(FN 100—1000 mN)
31
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
0 100 200 300 4000.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Temperature [°C]
Fric
tion
coeffi
cien
t
0 % at. Cu
3 % at. Cu
7 % at. Cu
22 % at. Cu
• Fixed and scannedtemperature
TiN
Friction coefficient
• Ball on discconfiguration
• Counterpart: alumina ball
• Speed: 5 cm/s
• Normal force:1 N
32
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
J
m
2
22
)(
3
111
n
ii
n
iii
n
iii
s
F
nL
A
nLr
rA
sF
rA
dssF
Vk
Wear rate coefficient - a definition
Worn volume of the sample per work unit done against friction force
-1.5-1
-0.50
0.5b) 100°C
0 100 200 300 400 500 600 700μm
μm
0 1000 2000 3000 4000 50000
0.2
0.4
0.6
0.8
1
Revolution number
Fri
ctio
n c
oeffi
cient
33
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Wear behavior: 20-400°C
0 5 10 15 20 25
10 -15
10 -14
10 -13
10 -12
Copper content (at. %)
Wear rate( m3/J )
10 -16
400°C
300°C
RT, 200°C
100°C
Wear rate
for TiN
RT – 0.8·10-14
200°C – 1.5·10-14
400°C – 3·10-15
34
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Wear behavior – "100°C effect"
RT: kF ~10-16 m3/
100°C: kF ~2·10-14 m3/J !200°C: kF ~10-16 m3/J0 200 400 600 800 1000
0
0.5
1
Raman shift [cm-1]
OutIn
0 200 400 600 800 10000
0.5
1
Raman shift [cm-1]
OutIn
0 200 400 600 800 10000
0.5
1
Raman shift [cm-1]
OutIn
Mo2N 0% Cu
35
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
6 at. % Cu
50 m
9 at. % Cu
50 m
50 m
22 at. % Cu
0 at. % Cu
50 m
1 at. % Cu
50 m
50 m
2.5 at. % Cu
Wear behavior – the influence of Cu addtion (100°C friction test)
kF ~10-16 m3/JkF ~2·10-14 m3/J
36
International Student Summer School „Nanotechnologies in materials engineering”
Warsaw - Koszalin 2006
Tomasz [email protected]
http://www.balticnet-plasmatec.org
Conclusions
Relatively low friction coefficient against alumina is observed in room temperature.
1-3 at. % of Cu additive increases hardness of Mo2N coatings.
Low wear rate is registered in temperatures bellow 250°C.
"The 100°C effect" is observed for samples with low content of copper. This effect is eliminated when films contain >6 at. % Cu .
Coatings gradually oxidize in temperature over 300°C.