Composite Coating

1
Composite Coating
? ? ? ????????? ????????
2

• Composite Coating
• - ? 2?? ??? ??? ?? ? ???? ??
• - ? 2?? ?? ?? ??? ?? ??
• - ? ? ?????
• - ?????, ?
• ? Application ??? ??, ??? ??, ????, ??
• Purpose
• - ? 2?? ?? ?? ?? ?
• - ?? ??? composite? ???
• ???? ??? PVD CVD
• - ????
• - ????? ???? 2? CVD?

3
????? ?? ??? ??

• Electrolyte
• - Ni Sulfamate 200 g/L
• - Ni Chloride 15.5 g/L
• - Boric Acid 2.5 g/L
• - Additives A or/and B
• - Sulfuric Acid 0 1.0 mol/L
• Temperature 40C
• Particle Loading
• - SiC (1.0 mm) 50 g/L
• - Al2O3 (0.4 mm) 100 g/L
• Current Density 200 mA/cm2
• Stirring Rate 200 rpm

Anode Ni ? Ni 2 2e (Nickel oxidation)
Cathode Ni 2 2e - ? Ni (Nickel
reduction) 2H 2e ? H2 (H2 evolution) SiC or
Al2O3 co-deposition
4
40
5
20
10
20min??
30min??
7Hr??
5
Effect of Sulfuric Acid in the Presence of
Additives (A) (B)
100 80 60 40 20 0
Additive ( A ) ( B )
Vol. of SiC in the coating
0.0 0.15 0.30
0.50 0.70
Amount of Sulfuric Acid (Mol/L)
6
Effect of Sulfuric Acid (Additives (A) (B))
0.15 mol/L
0.30 mol/L
0.70 mol/L
0.50 mol/L
7
Effect of Sulfuric Acid (Additives (A) (B))
0.15 mol/L
0.30 mol/L
1.00 mol/L
0.50 mol/L
8
Ni-Diamond Composite
9
Summary Future Work

• ????? ???? MMC (Metal Matrix Composite) Coating?
  ???? ??.
• ? Ni-based composite electroplating? ??
  ??? ??
• Ni-Alumina, Ni-SiC, Ni-Si, Ni-Diamond, etc.
• ?? ??
• (1) Additives ?? ?? composite
  electro-deposition mechanism ??
• (2) ? system? ??
• - Ni-based composite??? ? 2?? ?? ?, CNT,
  Diamond(nano)
• - Cu- Fe-based composites
• - Alloy matrix
• (3) Coating? ?? ? Application ?? ??? ?? ? ???
  ??

(1) ????? ????? IN 690 ?? (2) Wire Saw
Ni-SiC-Diamond Composite
10
TWO-STEP CVD
Principle in-situ formation of nanocomposite
coating by solid-state displacement reaction
between metal carbides, nitrides,
oxides, etc and silicon or aluminum.
1) Metal silicide-carbide nanocomposite
coatings ex) (1) M2C
5Si 2MSi2 SiC (where M Mo, W,
Nb, Ta, Ni, Fe, Co, etc.)
(2) MC 3Si MSi2
SiC 2) Metal silicide-nitride
nanocomposite coatings
ex) (1) 4M2N 19Si 8MSi2 Si3N4
(2) 4MN 11Si
4MSi2 Si3N4 3) Metal
silicide or aluminide-oxide nanocomposite
coatings ex) (1) 2MO
5Si 2MSi2 SiO2
(2) 3MO 5Al 3MAl
Al2O3
? 2?? ???? ????? ???? ????? ?? ???? ??? ?? ??
11
1) Columnar MoSi2 coating formed by conventional
reactive process
Thermal expansion coefficient MoSi2 8.5 x
10-6/K Mo 5.8 x 10-6/K Si3N4 2.9 x
10-6/K
MoSi2
Average size Columnar MoSi2 grains 2.2 mm
Mo substrate
2) Crack-free MoSi2Si3N4 nanocomposite coating
formed by displacement reaction
Average size Equiaxed MoSi2 grains 90 nm Si3N4
particles 60 nm
nanocomposite coating
Mo substrate
12
Applications
??? ??/??/???/??? ?? ????