[PDF] - Application of Nanostructured powders synthesized by new chemical PDF Document

SLIDE 1

2003. 10

Byoung-Kee Kim

Korea Institute of Machinery and Materials,

Application of Nanostructured powders synthesized by new chemical processes

Characteristics of Nanopowder Materials

KIMM Korea Institute of Machinery and Materials

Enhanced catalytic properties
Enhanced absorption ability
Capilary Condensation
Enhanced catalytic properties
Enhanced absorption ability
Capilary Condensation

Surface Effect

Appearance of New Phases
Decrease of Melting Point
Polycrystallization of Single Crystal
Enhanced Scattering Effect of Waves
Appearance of New Phases
Decrease of Melting Point
Polycrystallization of Single Crystal
Enhanced Scattering Effect of Waves

Bulk Effect

Electric and heat transfer
Compressability
Solid state reactivity
Electric and heat transfer
Compressability
Solid state reactivity

Interaction between Nanopowders

~3As 6As 10 Ni Catalytic Property (As : standard Activity) 700℃ ~200℃ ~1000℃ 200 220 Ni W Sintering Temperature 20mK 2.0mK 100 Ag Heat Transfer 3.4K 5.3K 90 Al Transition Temperature of Superconductivity 2~5% 95% 100 Au Light Absorption (6~10㎛) 1300K 430K 933K 370K 30 40 Au In Melting Point ~470Oe 1030Oe 50 Fe Magnetic Property Micro- materials Nano- materials Size(Å) Materials Property

SLIDE 2

Application Field of Nanopowder Materials

KIMM Korea Institute of Machinery and Materials

Electronic Optical Electronic Optical Magnetic Magnetic Structural Structural Others Others

◆ Optoelectronic devices ◆ Passive electronic devices ◆ IC substrate ◆ Thermistor and varistor ◆ Piezoelectric actuators ◆ CMP ◆ Advanced tones ◆ Diagnostic contrast agents ◆ Ferrofluids ◆ Magnetic Recording ◆ Magnetic Refrigerator ◆ Cutting tool ◆ Die ◆ Coating ◆ Abrasive components ◆ Catalysts ◆ Chemical sensors ◆ Energy storage devices ◆ Pigments ◆ Membranes

Research of Nanopowders in KIMM

KIMM Korea Institute of Machinery and Materials

Chemical Sensor, Membranes, Filter, TiO2 photocatalysts Chemical/Catalytic Materials Thermistor, Varistor, Piezoelectric actuator Cu-Al2O3 electrode, W-Cu heat sink Electric/Electrode Materials Ferrofluid, Magnetic refrigerator, Recording media, Hard/Soft Magnets, Fe/Co magnetic materials, Nd-Fe-B hard magnet Magnetic Materials Abrasives, Cutting tools, CMP, Wear-resistant components WC-Co hard materials Tool Materials Materials

Area

SLIDE 3

Mechanical Properties of WC/Co Mechanical Properties of WC/Co

Chemical compositions(contents of Co)

Particle size of hard phase(WC) Homogeneity of WC/Co (mean free path)

Chemical compositions(contents of Co)

Particle size of hard phase(WC) Homogeneity of WC/Co (mean free path) Reduction of WC size Decrease of mean free path Reduction of WC size Decrease of mean free path Hardness Compressive Strength TRS Strength Wear Resistance Hardness Compressive Strength TRS Strength Wear Resistance Key for high mechanical properties

Fabrication of very fine WC Higher homogeneity of WC and Co phases

Key for high mechanical properties

Fabrication of very fine WC Higher homogeneity of WC and Co phases

KIMM Korea Institute of Machinery and Materials

Manufacturing of WC/Co Alloys Manufacturing of WC/Co Alloys

A P T p

w

d e r C a l c i n a t i

n

s Reduction Carburization Milling(+C) Milling(+Co) W, C

me

t a l

r

g a n i c s E v a p

r

a t i

n

/ C a r b u r i z a t i

n

WC , WC

C
W,

C

c

h l

r

i d e s S p r a y d r y i n g Reduction/ Carburization Reduction/ Carburization Milling(+C) Removal of Chlorides

Solid Phase Process Liquid Phase Process Gas Phase Process G.S. > 300nm G.S. > 100nm G.S. < 30nm

Korea Institute of Machinery and Materials KIMM

SLIDE 4 Temperature(℃) 400 800 1200 W2(C,O) W W2C WC H2/He He He H2/He H2/CH4 H2/CH4 20nm 10nm

l
w

p r e s s u r e ( 1

3

a t m)

s

i z e : 5 n m

l
w

p r e s s u r e ( 1

3

a t m)

s

i z e : 5 n m Temperature(℃) Concentration of Methane WC WC+W2C W2C + W WC +W2C+ W L

w

C H i g h C 800 1000 1200 1400 sccm 20 40 60 80 100 120 140 Total : 600sccm

n

WC

p

w

d e r n

WC

p

w

d e r

KIMM Korea Institute of Machinery and Materials

C

a

t i n g

f

n

WC

, C

p
w

d e r

Carbon coating WC powder

WC

p

w

d e r : 4 n m

WC

p

w

d e r : 4 n m 4nm Oxide coating Co, Fe powder

C
r

e ( me t a l ) / S h e l l ( O x i d e )

O

x i d e s h e l l: 3 n m)

C
r

e ( me t a l ) / S h e l l ( O x i d e )

O

x i d e s h e l l: 3 n m) 5 n m F e F e

x

i d e C

C
x

i d e 200 400 600 800 1000 100 104 108 112 116 Co oxidation Weight Change(%) Temperature(

C)

WC(C:10.5%)/CVC WC(C:5.78%)/CVC WC-10Co/TCP Taegutech KIMM Korea Institute of Machinery and Materials

SLIDE 5 10 9 8 7 6 5 100 200 300 400 500 600 700 Load(kgf) Displacement(mm) 10nm-1.0% 10nm-2.0% 100nm-1.0% 100nm-2.0% 2.2 3.09 100nm C 1.85 2.02 100nm (granule) B 0.77 18.4 20nm A (NRL) A.D. (g/cm3) BET (m2/g) Power size type

C

m

p a c t a b i l i t y

f

n

WC

p

w

d e r C

m

p a c t a b i l i t y

f

n

WC

p

w

d e r

C

m

p a c t d e s i t y 4 7 % Rearrange

f particles

KIMM Korea Institute of Machinery and Materials

S i n t e r b i l i t y

f

n

WC

/ C

p
w

d e r

Solid sintering temp.

WC

( 2 n m) + C

(

2 n m) : 8 3 5

C
WC

( 2 n m) + C

(

1 n m) : 8 9

C
WC

/ C

(

1 n m) : 1 1

C
WC

/ C

(

2 n m) : 1 7

C
WC

( 2 n m) + C

(

2 n m) : 8 3 5

C
WC

( 2 n m) + C

(

1 n m) : 8 9

C
WC

/ C

(

1 n m) : 1 1

C
WC

/ C

(

2 n m) : 1 7

C

835oC 890oC 1010oC 1070oC 835oC 890oC 1010oC 1070oC 20nm→2㎛ ( x 100) 100nm→1㎛ ( x 10) WC / C

(

2 n m) WC ( 2 n m) / C

(

1 n m) WC / C

(

2 n m ) WC / C

(

1 n m )

s

i n t e r i n g t e m p : WC s i z e ( 1 7 →8 3 5

C

) C

s

i z e ( 8 9 →8 3 5

C

)

a

b n

r

m a l g r a i n g r

w

t h ( 1 0t i m e s , ) G r a i n g r

w

t h i n h i b i t

r

s KIMM Korea Institute of Machinery and Materials

SLIDE 6

P l a s m a s i n t e r i n g / g r a i n g r

w

t h i n h i b i t

r

P l a s m a s i n t e r i n g / g r a i n g r

w

t h i n h i b i t

r

WC

1

C

.

6 V C r

u

n d , 7 n m ( x 4 ) WC

1

C

.

6 V C r

u

n d , 7 n m ( x 4 ) WC

1

C

f

a c e t t e d s h a p e 1 ㎛ ( x 5 ) WC

1

C

f

a c e t t e d s h a p e 1 ㎛ ( x 5 ) Conventional WC-10Co

Nano. WC-10Co
H

i g h D i s l

c

a t i

n

D e n s i t y

S

t a c k i n g F a u l t s

D

i s l

c

a t i

n

f r e e WC g r a i n s

T

w i n s i n WC g r a i n s P l a s m a s i n t e r i n g KIMM Korea Institute of Machinery and Materials

Properties of Nanostructured WC-Co Alloy

>1.0㎛ <0.1㎛ 1650 200 1900 2050 350 1.2E-8 2.1E-9 100 200 300 400 500 600 700 800 900 1000 400 600 800 1000 1200 1400 1600 1800 2000 Nanophase Submicron(0.6µm) Submicron(1.9µm) Hardness(Hv) Temperature(o C) KIMM Korea Institute of Machinery and Materials Sintered (㎛) Hv (kgf/mm2) TRS (kgf/mm2) Wear rate (mm3/m) TCP MCP S u b m i c r

n

SLIDE 7

Nano sized Fe and Co Magnetic Materials

KIMM Korea Institute of Machinery and Materials

Magnetic Fluid : Magnetite(Fe3O4) Saturation Magnetization of Fe = 2 times of that of Fe3O4

Coercivity ; proportional to inverse of particle size (Hc = a+b/D)

Synthesis of nano-sized Fe ⇒ High performance magnetic fluid

materials( Saturation Magnetization : 1500emu/cm3, Coercivity : 3000Oe) Development of Fe based nanopowder for magnetic fluids by Chemical Vapor Condensation Development of Fe based nanopowder for magnetic fluids by Chemical Vapor Condensation

KIMM Korea Institute of Machinery and Materials

KIMM

30 35 40 45 50 55 60 65 70 75 80 Co nanoparticles (fcc-type) Fe nanoparticles (bcc-type) Intensity (arb. unit) 2 θ Co Fe Core Crystalline Fe Core Crystalline Fe Shell Crystalline Fe

xides

Shell Crystalline Fe

xides

Microstructures of Fe Nanoparticles

5 nm

SLIDE 8 KIMM Korea Institute of Machinery and Materials

KIMM

10
8
6
4
2

2 4 6 8 10 (d ) (c) (b ) (a) Relative Transmission V e lo c ity (m m /s ) S a m p les α

F

e (% ) B u lk M id d le S u p er- p a ra m agn etism (% ) F e 3O 4 (% ) M ea n siz e (n m ) (a ) 2 9 8 5 .3 9 (b ) 2 5 7 5 ~ 7 .0 (c) 3 4 2 4 2 1 2 1 1 .3 2 (d ) 7 1 2 ~ 1 2 .0 Superpara- Ferro- Ferro- Superpara- (a) (b) (c) (d) Superpara- Ferro-

Mössbauer spectroscopy of Fe nanoparticles

KIMM Korea Institute of Machinery and Materials

KIMM

Core Crystalline Fe-Co Core Crystalline Fe-Co Shell Crystalline Fe and Co oxides Shell Crystalline Fe and Co oxides Twin structure Twin structure

Microstructures of Fe-Co nanoparticles

SLIDE 9 KIMM Korea Institute of Machinery and Materials

KIMM

30 35 40 45 50 55 60 65 70 75 80 Carrier gas: Ar + 6%O2 Carrier gas: He Carrier gas: Ar

2 θ

BCC Co

+ HCP Co

BCC Co BCC Co

+ + HCP Co

HCP Co BCC Co BCC Co BCC Co Co oxide Co oxide Co oxide

Phases of Co nanoparticles with carrier gases

KIMM Korea Institute of Machinery and Materials

KIMM

Different phases with different Co content Different phases with different Co content Saturation magnetization reaches highest value near 40 wt% Co Saturation magnetization reaches highest value near 40 wt% Co 10 15 20 25 30 35 40 45 50 55 60 20 40 60 80 100 120 Ms (emu/g) Co content 30 4 0 5 0 6 0 7 0 8 0

2θ

Intensity (arb. unit) F e-47 C o F e-50 C o F e-40 C o F e -3 4 C o F e-10 C o F C C -F e(C o)

B C C -F e(C o)
Phases and saturation magnetization

SLIDE 10

Nanostructured TiO2 photocatalytic materials

KIMM Korea Institute of Machinery and Materials

Decrease of particle size

Improved UV scattering
Enhanced photocatalytic activity
Improved gas sensing property
Enhanced opto-electronic property

Synthesis of nano sized TiO2 powders by Chemical

Vapor Condensation process (Non-Agglomerated 10nm powder)

KIMM Korea Institute of Machinery and Materials

KIMM

Microstructure of Nano-sized TiO2 Powder

Anatase Rutile 20 25 30 35 40 45 50 55 60 Intensity 2θ size : 10nm loose agglomerates phases : Anatase + Rutile (<2%) size : 10nm loose agglomerates phases : Anatase + Rutile (<2%)

SLIDE 11 KIMM Korea Institute of Machinery and Materials

KIMM

Phase Change Depending on Powder Size

[100] zone axis (110) type planes Anatase a=3.75Å, c=9.51Å Anatase a=3.75Å, c=9.51Å Rutile ~60nm Rutile ~60nm

Nanostructured W-Cu heat sink materials

KIMM Korea Institute of Machinery and Materials

Poor sinterability due to the negligible solid solubility

between W and Cu

Conventional Process

Infilteration : Low thermal & electric conductivity

due to the addition of sintering activator

Liquid phase sintering : Low properties due to larger W size

Development of new process to achieve high density

nanostructured W/Cu materials, using nanostructured powder (W : 60nm)

SLIDE 12

Microstructures of W/Cu Alloys

Mixing method W:0.51%, Cu:20% Thermochemical method (W-20wt%-0.5wt%Co) Mechano-thermochemical method(II) Reduced powder (200C/1h+700C/1h) Mechano-thermochemical method(I) Burnt out powder, Two-reduction step KIMM Korea Institute of Machinery and Materials

Sinterabilty of Nanostructured W/Cu Powders

1000 1100 1200 1300 20 30 40 50 60 70 80 90 100 Green density Sintering density Burnt out powder (process I) Reduced powder (process II) Metal mixed powder Green density Burnt out powder Reduced powder Metal mixed powder Cu melting point Green density Relative density (%) Sintering temperature (oC) KIMM Korea Institute of Machinery and Materials

SLIDE 13

Comparison of Thermal Properties

7.25 7.88 7.80 6.5 (6.8-7.6) 5.4 (6.0-7.0) 8.0(8.1-8.9) 6.5 (7.2-8.0) Thermal Expansion Coefficient (ppm/K) 221.3 245.8 233.0 170 (180-210 141 (180-210 242 (180-210 207 (180-210) Thermal Conductivity (W/mK) 223.2 223.2 223.2 300.0 294.5 240.1 223.2 Specific Heat (J/Kg·K) 15.16-L 14.85-T 15.43-L 15.17-T 15.48-L 15.17-T 9.81 9.89 14.63 15.94 Density (g/㎠) W-20Cu KIMM 750-4 W-20Cu KIMM 700-8 W-20Cu KIMM 700-8 Mo-20Cu Thermkon

70M

Mo-15Cu Thermkon

65M

W-20Cu Thermkon

83

W-20Cu Thermkon

76

KIMM Korea Institute of Machinery and Materials

Prospect of Nanopowder Materials

KIMM Korea Institute of Machinery and Materials

Thin Films Electro-optical Device and Ferroelectrics Superhard Materials Drilling, Mining and Machine Tools Protective Coatings Transportation Energy, Chemical Industries Advanced Nanocomposites Energy And Aerospace Industries

Ceramics Cermet Metals

5 10 15

Years