Tribomechanical Properties of DLC Coatings Metallic and ... › ... › 2016 › 09 ›...
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Transcript of Tribomechanical Properties of DLC Coatings Metallic and ... › ... › 2016 › 09 ›...
T r i b o m e c h a n i c a l P r o p e r t i e s o f D L C C o a t i n g s D e p o s i t e d b y M a g n e t r o n S p u t t e r i n g o n
M e t a l l i c a n d I n s u l a t i n g S u b s t r a t e s
Indianapolis, May 10th, 2016
Dr. Iván Fernández Martínez
D i a m o n d L i k e C a r b o n ( D L C )
Diamond-like Carbon (DLC) is a metastable form of amorphous carbon with significant sp3 bonding. DLC coatings are of interest in a wide variety of applications to provide low friction and high hardness and wear resistance.
Applications - Glass: anti-scratch. - Molds: prevent plastic transfer - Engine parts: low friction (a-C). - Space parts: low friction (a-C:H). - Cutting tools: lubricated and dry
conditions. - Oil & gas: super lubricity in pipes. - ….
D L C : S t a t e o f t h e a r t
A. Voevodin, Surf. Coat. Technol. 82 (1996) 199–213. J. Robertson, Surf. Coat. Technol. 50 (1992) 185–203.
Ion assistance required ~ 100eV
Prof. Wolf-Dieter Munz “Industrial scale deposition of well adherent and low friction DLC coatings grown by HIPIMS and anode assisted unbalanced magnetron” – Private discussion
D L C h a r d c o a t i n g m a g n e t r o n d e p o s i t i o n
Anode to extend the plasma
Magnetically linked magnetrons
D L C h a r d c o a t i n g m a g n e t r o n d e p o s i t i o n
Prof. Wolf-Dieter Munz “Industrial scale deposition of well adherent and low friction DLC coatings grown by HIPIMS and anode assisted unbalanced magnetron” – Private discussion
Bias required Glass? Plastics?
55GPa Microhardess, comparable to filtered arc
I o n a s s i s t e d d e p o s i t i o n o n i n s u l a t o r s ? Magnetron magnetic design (electron filter) + modified asymmetric bipolar pulsed PS
Proprietary technology: Patent application number GB1605162.5 (March 2016)
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9 2b 8c
- Positive ion bombardment - No electron bombardent :
Reduced thermal load?
Magnetron size 400x100mm2 (industrial relevant) – WC, Graphite targets HIPIMS Ti/Cr + WC improves coating adhesion Optimized magnetic field configuration to enhance ion assisted deposition
Proprietary technology: Patent application number GB1605162.5 (March 2016)
I o n a s s i s t e d d e p o s i t i o n o n i n s u l a t o r s ?
Magnetron size 400x100mm2 (industrial relevant) – WC, Graphite targets HIPIMS Ti/Cr + WC improves coating adhesion Optimized magnetic field configuration to enhance ion assisted deposition
Proprietary technology: Patent application number GB1605162.5 (March 2016)
I o n a s s i s t e d d e p o s i t i o n o n i n s u l a t o r s ?
Sample position
3 energy regimes are measured
I o n a s s i s t e d d e p o s i t i o n o n i n s u l a t o r s ?
Hardness value taken at around 10% total DLC thickness
Load partial unload curve
Hysitron TI950 Triboindenter Berkovich tip indenter BKL4
C o a t i n g H a r d n e s s : a b o v e 3 0 G P a o n f l o a t i n g s u b s t r a t e
Hardness = 32 Gpa Young modulus = 220 Gpa 500nm thick DLC
D L C h a r d c o a t i n g m a g n e t r o n d e p o s i t i o n
Prof. Wolf-Dieter Munz “Industrial scale deposition of well adherent and low friction DLC coatings grown by HIPIMS and anode assisted unbalanced magnetron” – Private discussion
Bias required
15GPa Microhardess with -75V Bias!
Proprietary technology: Patent application number GB1605162.5 (March 2016)
H a r d n e s s > 3 0 G P a H a r d n e s s < 1 2 G P a
I o n a s s i s t e d d e p o s i t i o n o n i n s u l a t o r s ?
C o m m e r c i a l D C - P u l s e d P S M o d i f i e d D C - P u l s e d P S
S E M i m a g e : D e n s e D L C f i l m
SEM cross section of WC/DLC coating
Rockwell HRC tests - 150kg - Diamond indenter conical tip
A d h e s i o n o n m e t a l s : S t a n d a r d R o c k w e l l ( D a i m l e r o r M e r c e d e s ) t e s t s
HF1
DLC on HSS
HSS substrate surface
DLC coated surface DLC delaminated coating
Cr + WC + DLC on HSS
NO DLC coating delamination
Indentation HF5 HF1
675mN load 5um tip radius
Rockwell HRC tests, 150kg
Diamond indenter conical tip
HF1
A d h e s i o n o n m e t a l s : R o c k w e l l a n d n a n o - s c r a t c h t e s t s
HF1
F r i c t i o n a n d w e a r – A S T M G 9 9 S t a n d a r d t e s t
SS304 uncoated substrate DLC coated SS304
HF1
0 2000 4000 6000 80000.0
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Frict
ion
coef
ficie
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t (s)
F r i c t i o n a n d w e a r – A S T M G 9 9 S t a n d a r d t e s t
Ongoing stress measurements in DLC coatings
L o w a c c u m u l a t e d s t r e s s @ h i g h h a r d n e s s
Biased process : high DLC coating stress N4E process : low DLC coating stress
D L C c o a t i n g o n G l a s s
Delamination problem: Need to reduced thicknesses and ion bombardment
Hardness in the range of 20GPa for 40nm thick DLC layer
DLC
Glass
D L C c o a t i n g o n G l a s s
Substrate can be pre-treated with reactive gases such as oxygen
+485V
Current to floating potential (10mV/A)
D L C c o a t i n g o n G l a s s
8006004002000
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Z[nm
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8006004002000
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Untreated glass substrate
Oxygen treated glass substrate
RMS roughness : 2.6 nm
RMS roughness : 1.4 nm
D L C c o a t i n g o n G l a s s : n a n o - s c r a t c h t e s t s
500mN critical load – 5 micron tip radius
Characteristics - Acceleration of a test probe (diamond tip)
towards sample.
- Impact energy can be controlled and quantified.
- multiple impacts.
- Strain rate: 100-1000 (s-1).
* J.M. Wheeler et al., Surface & Coatings Technology 232 (2013) 264–268 “Analysis of failure modes under nano-impact fatigue of coatings via high-speed sampling“
N a n o - i m p a c t t e s t i n g o n D L C c o a t i n g s
Loads: 5, 10, 15mN
N a n o - i m p a c t t e s t i n g o n D L C c o a t i n g s
Advantages - Produce contact fatigue.
- Adhesion failure without substrate deformation
- Measure dynamic instead of static hardness
Simulate thin film in-situ service for machining operations
* J.M. Wheeler et al., Surface & Coatings Technology 232 (2013) 264–268 “Analysis of failure modes under nano-impact fatigue of coatings via high-speed sampling“
N a n o - i m p a c t t e s t i n g a - C : H o n S i
Test conditions - Conical tip. R= 5(µm) - Impact Height: 10 (µm) - Rest time: 500 (ms) - Specimens: a-C and a-C:H on Si
a - C o n M 2 s t e e l w i t h C r - H I P I M S i m p l a n t .
HF1 Rockwell DLC on M2 Steel Multiple Impact with Previous Conditions Multiple impacts: 30 mN during 1200s.
No delamination!
Loads: 5 to 30mN Load: 30mN
Guggenheim Museum, Bilbao
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Characterisation techniques and Properties
Novel 2D materials
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Tribological coatings
Energy conversion (solar, batteries) and catalysis
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