1. SURFACE ENGINEERING (1)
VAPOR DEPOSITION
Prof. Priit Kulu, Eron Adoberg

2. Surface properties of material/part
Wear
mechanical;
corrosive-mechanical.
Criteria: wear resistance (by mass/volume, relative)
Methods of surface reinforcement
peening;
surface alloying and hardening;
coatings (sprayed coatings, vapor deposited coatings, cladded coatings, galvanic coatings, diffusion coatings);
metal cladding (bimetal materials).

3. Deposited coatings CHEMICAL ELECTROCHEMICAL THERMOCHEMICAL
ion coating
CHEMICAL
ELECTROCHEMICAL
THERMOCHEMICAL
THERMOCOATING
VAPOR DEPOSITION
MECHANICAL
ion transfer
(ion alloying)
ion mixing/dilution
ion composite
coating

4. Comparison of the coating processes

5. Thin hard coatings
Ceramic compounds – metals’ oxides, carbides, nitrides.
Coatings with thickness up to 10 μm are considered as thin coatings.
Advantages:
abrasive, adhesive, etc. wear decreases;
pad growth avoided;
tribological properties improve, thus improving its service life;
need for lubrications decreases.
Coating does not affect the geometry and size of the coated detail.

6. Coatings’ processes

7. Coating process – PVD 1 – cathode; 2 – accelerators; 3 – anode.
lower process temperature (250 – 600 ºC) in comparison with CVD process;
electrical or magnetic field is applied.

8. Coating process – CVD Higher process temperature (600 –
1100 ºC) in comparison with PVD process;
Chemical reaction is applied.

9. Coating cycle

10. PVD-Coating with Dynamic Rotating ARC-Cathodes
LARC®: LAteral Rotating ARC-Cathodes
rotary table
magnetic
confinemen
system_2
substrates
door or backside shield
confinement
system_1

14. Structures’ types of the coatings

15. Microstructure of coatings (1)
SEM image of fractured surface of PVD coating on hardmetal. a- TiN coating: 1 – HM substrate; 2 – Ti adhesion layer; 3 – TiN coating; 4 – coating surface with microdroplets. b- multilayer TiAlN: 1– HM; 2 – Ti adhesion layer; 3 – TiN layer; 4 – TiAlN layer; 5 – TiAlN/AlN multilayer coating; 6 – TiAlN coating; 7 – coating surface with microdroplets

16. Microstructure of coatings (2)
SEM images of fractured surface of PVD coatings on nitrided steel: a– monolayer TiN, b– monolayer TiCN and c– multilayer TiAlN

17. Gradient coatings Large Al content
The content of coating’s hard component – AlN – gradiently increases through the coating giving the coating’s surface the largest hardness value.
TiN adhesion layer
Small Al content

18. Multilayer coatings have bigger toughness.
Layer structure hinders cracks’ development.
Multilayer coatings are applied, where dynamic loads are present.
TiAlN+TiN (allikas: MUK)

20. Nanocomposite coatings (1)
2 phases appear during the deposition process: nanocrystalline AlTiN (hard) and amorphous Si3N4 (tough)
Advantages:
very high nanohardness and toughness
very high temperature resistance

21. Nanocomposite coatings (2)

22. DLC coatings
DLC (diamond-like carbon) coatings: mechanical, chemical, optical and electric properties are similar to that of natural diamond, but does not have an even crystalline structure;
DLC is deposited as the finish layer at the top of the coating.
large hardness;
chemical inertness;
low coefficient of friction

23. Hard coatings’ properties
Color
Hardness
(GPa)
Young’smodulus
E (Gpa)
Thickness of coating (μm)
COF
Maximum application temp.°C
TiN
TiCN
TiAlN (mono/
multilayer)
AlTiN
nACo®
(AlTiN/Si3N4)
CrN
AlCrN
TiAlCN+CBC*
(CBC – carbon-based top layer)
nACo®+CBC*
gold
copper
violet-black
black
violet-blue
silver
blue-gray
grey 24 32
35/28 38 45 18
20/30
438±80
500±90
301±90
336±13
323±13
1 – 7
1 – 4
1-7
1-4
1,5 – 5
1 – 6
0,55
0,2
0,5/0,6
0,7
0,45
0,3
0,6
0,15
600
400
800/700
900
1200
700
1000
500
450

24. Diagram of sliding wear testing results by RT
Diagram of sliding wear testing results by RT. Drum (C45 steel) wear track width and versus coatings E/H ratio.

25. Application of PVD and CVD coatings

26. Trends in the PVD coatings

27. Coating application areas

28. Applications (1) Cutting tools: TiAlN AlTIN TiAlCN nACo® (AlTiN/Si3N4)
AlCrN
TiAlCN
nACo® (AlTiN/Si3N4)
nACRo (AlCrN/Si3N4)
milling distance Lf [m]

29. Applications (2)
Punches and dies:
TiN
TiCN
TiAlCN + CBC
AlCrN

30. Applications (3) Pressing and casting molds Tribology TiN CrN ZrN
AlCrN
TiAlCN + CBC
Tribology
TiAlCN + CBC
nACo +CBC
nACRo + CBC
DLC

31. Thank you for the attention! Questions?