1 SURFACE ENGINEERING (1) VAPOR DEPOSITION Prof. Priit Kulu, Eron Adoberg.
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Transcript of 1 SURFACE ENGINEERING (1) VAPOR DEPOSITION Prof. Priit Kulu, Eron Adoberg.
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SURFACE ENGINEERING (1)
VAPOR DEPOSITION
Prof. Priit Kulu, Eron Adoberg
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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).
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Deposited coatings
• CHEMICAL
• ELECTROCHEMICAL
• THERMOCHEMICAL
• THERMOCOATING
• VAPOR DEPOSITION
• MECHANICAL
ion coating
ion transfer
(ion alloying)
ion mixing/dilution
ion composite
coating
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Comparison of the coating processes
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Thin hard 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.
Ceramic compounds – metals’ oxides, carbides, nitrides.
Coatings with thickness up to 10 μm are considered as thin coatings.
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Coatings’ processes
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Coating process – PVD1 – cathode;2 – accelerators;3 – anode.
• lower process temperature (250 – 600 ºC) in comparison with CVD process;
• electrical or magnetic field is applied.
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Coating process – CVD
• Higher process temperature (600 –
1100 ºC) in comparison with PVD process;
• Chemical reaction is applied.
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Coating cycle
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PVD-Coating with Dynamic Rotating ARC-Cathodes
LARC®: LAteral Rotating ARC-Cathodes
rotary table
magneticconfinemensystem_2
substrates
door or backside shield
magneticconfinement
system_1
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Structures’ types of the coatings
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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
Microstructure of coatings (1)
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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
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Gradient coatings
Large Al content
TiN adhesion layer Small Al content
The content of coating’s hard component – AlN – gradiently increases through the coating giving the coating’s surface the largest hardness value.
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Multilayer coatings
TiAlN+TiN (allikas: MUK)
Layer structure hinders cracks’ development.
Multilayer coatings are applied, where dynamic loads are present.
Multilayer coatings have bigger toughness.
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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
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Nanocomposite coatings (2)
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DLC coatings
DLC is deposited as the finish layer at the top of the coating.
• large hardness;
• chemical inertness;
• low coefficient of friction
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;
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Hard coatings’ properties
Coating ColorHardness
(GPa)
Young’smodulusE (Gpa)
Thickness of coating
(μm)COF
Maximum application
temp.°C
TiNTiCNTiAlN (mono/multilayer)AlTiNnACo® (AlTiN/Si3N4)CrNAlCrNTiAlCN+CBC*(CBC – carbon-based top layer)nACo®+CBC*
goldcopperviolet-black
blackviolet-blue
silverblue-graygrey
grey
2432
35/28
3845
1832
20/30
20/30
438±80500±90301±90
336±13323±13
1 – 71 – 41 – 4
1 – 41 – 4
1-71-4
1,5 – 5
1 – 6
0,550,2
0,5/0,6
0,70,45
0,30,6
0,15
0,15
600400
800/700
9001200
7001000
500
450
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Diagram of sliding wear testing results by RT. Drum (C45 steel) wear track width and versus coatings E/H ratio.
190
8590
100
180
2 2,62,32,130
15
30
45
60
75
90
105
120
135
150
165
180
195
210
E/H: TiCN 18,8 TiN 15,4 TiAlN 15,2 AlTiN 14,4 NaCo 11,1
C45 s
teel
dru
m s
lid
ing
wear
test
wear
track w
idth
an
d d
ep
th (
μm
)
wear track width
wear track depth
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Application of PVD and CVD coatings
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Trends in the PVD coatings
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Coating application areas
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Applications (1)Cutting tools:• TiAlN• AlTIN• AlCrN•TiAlCN• nACo® (AlTiN/Si3N4)• nACRo (AlCrN/Si3N4)
milling distance Lf [m]
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Applications (2)
Punches and dies:• TiN• TiCN• TiAlCN + CBC• AlCrN
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Applications (3)Pressing and casting molds• TiN• CrN• ZrN• AlCrN• TiAlCN + CBC
Tribology• TiAlCN + CBC• nACo +CBC• nACRo + CBC• DLC
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Thank you for the attention!
Questions?