CVD diamond coatings for industrial applications
Filipe J. Oliveira
Rui F. Silva, Flávia A. Almeida,
Ermelinda Salgueiredo
CICECO
Universidade de Aveiro
Portugal
Florinda Costa,
Margarida Amaral,
António J.S. Fernandes
I3N
Universidade de Aveiro
Portugal
CVD diamond deposition methods used at UA
HFCVD
H2+CH4+…
Filament (Ta or W)
Thermocouple
substrate
Sample heater
Vacuum pump
Reactor wall
MPCVD
H2+CH4
coupler
plasma
ball
substrate
Wave
guide 3 stub tuner
Microwave
head
Microwave quartz
window
Substrate holder
Reactor wall
Vacuum pump
Si3N4 ceramic - CVD diamond system
SUBSTRATES
- REQUIREMENTS FOR MECHANICAL APPLICATIONS
- Excellent interfacial adhesion;
- High thermal and chemical compatibility
HIGH ADHESION
Si3N4
-CERAMICS
CTE≈
≈DIAMOND
CHEMICALLY FIT
MICROANCHORING
HV + KIC
CVD diamond - Characterization
- Micro (MCD) and Nanocrystalline (NCD) grades
µ-Raman
AFM
Intensity (a.u.)
SEM
50 µm
1000
1100
1200
1300
1400
-1
1500
1600
1700
1500
1600
1700
Raman shift (cm )
MCD
Intensity (a.u.)
30 µm
50 µm
NCD
1000
3 µm
1100
1200
1300
1400
-1
Raman Shift (cm )
CVD diamond - Tribological Characterization
Self mated, lubricated and unlubricated tests
- Pin on disk
- Ball on flat
From micro loads up to 100N
- Ring on Ring
- Friction coefficient: 0.01 to 0.05
- Wear coefficient: 10-9mm3N-1m-1
Application of CVD diamond - Cutting tools
Cutting tools produced at UA
Direct coat of CVD diamond
CVD diamond brazed to cutting inserts
• Film thickness up to 50 µm
Thick CVD diamond
sheet
Brazing alloy (Ti-Cu-Ag)
Film thickness up to 500 µm
Materials machined by diamond tools
Metallic
composites,
green
One
of alloys,
the most
difficult:
ceramics and …
Sintered carbide (hardmetal)
Usual Machining method
Grinding followed by polishing
(slow processes)
Turning tests at an industrial facility
CNC lathe
Tool holder
Roughing operation
3-axes Dynamometer
cutting speed
= 20 m/min
depth-of-cut = 0.2 mm
feed
= 0.1 mm/rev
Finishing operation
WC-Co Workpiece
Fc – main cutting force
cutting speed
= 60 m/min
F – feed force
depth-of-cut f = 0.05 mm
Fd –= 0.04
depth-of-cut
feed
mm/rev force
Some results in roughing (1 CVD tool + 1 PCD tool)
TP-CVD
TP-PCD
300 µm
300 µm
Industry
standard for
roughing
What was achieved: Grinding x turning with CVD Diamond
Improved workpiece surface quality
Reduction of production steps
Reduction of product delivery time
Lowering or elimination of cooling lubricants
Single-step complex-shape machining
Less energy comsuption
OTHER PROTOTYPES TESTED
CVD diamond coated
NCD diamond
Si3N4 seal rings
coated drill bits
Acknowledgments
and to You all
and to You all