Effect of HSMF on Electrodeposited Ni-Fe Membrane-- Crystal Morphology and

Magnetism Performance

Yunbo Zhong, Yanling Wen, Zhongming Ren, Kang Deng, Kuangdi Xu

Shanghai Key Laboratory of Modern Metallurgy & Material Processing

German-Sino Workshop on EPM, October, 16-19, 2005, Dresden, Germany

Influence on electron transfer kinetics ?

Influence on mass transportMHD effect

Influence on Surface Diffusion 、 Necleation 、Crystal Growth?

Electrochemical Crystallization in HSMF

H2OMe2+

MetalMembrane

E0

ChargeTransfer

SurfaceDiffusionNucleation

CrystalGrowth

Bulk Solution

BoundaryLayer

2

02BUM

2

02BU Ls

M

Variation of Free Energy in the process of Electro-deposition of NiFe membrane

The χ data is very lacking, and the magnetism of ions in solution are not very clear

Magnetic susceptibility (χ) of Ni and Fe atoms are higher than that of other non magnetism atoms

PID TemperatureController

B

I

B I⊥

B

I

B//I

Magnetic Field Center

Nitrogen

Thermocouple

Water-cooling Pipe

Supercon-ductive Coil

HeaterElectrolyte

Heat Insulator

Quartz Pipe

Electrode

B

+ -

Fix Block

Sketch Map of Experimental Equipment

Nickel Plate

Copper Foil

0

1

2

3

4

5

6

7

8

9

10

11

-20 -15 -10 -5 0 5 10 15 20

Distance to Magnetic Field Center, z /cm

Mag

netic

Flu

x D

ensi

ty, B

/T

- 500

- 400

- 300

- 200

- 100

0

100

200

300

400

500

- 20 - 15 - 10 - 5 0 5 10 15 20

Di stance to Magneti c Fi el d Center, Z/ cm

BdB/

dz，T2/m

Distribution of High Static Magnetic Field

Effect of magnetic field on electrodeposited Ni-Fe membrane

When I⊥B

B

IMagnetic Field

Center

Surface SEM pictures of NiFe membrane electrodeposited in various magnetic fields(J=4A/dm2)

0T 4T 6T

8T 10T 12T

Across-section SEM pictures of NiFe membrane electrodeposited in various magnetic fields(J=4A/dm2)

( -electrodeposit growth direction )

0T 4T 6T

8T 12T10T

B

XRD patterns of the NiFe membranes

electrodeposited in different magnetic flux density

Strength ratio of three main peaks: I(111):I(200):I(220)=

( 0T)100:54.3:4.3; (04T)100:24.7:6.2; (06T)100:26.9:6.4; (08T)100:28.8:7.1; (10T)100:28.2:8.4; (12T)100:19.1:6.6

(111)

(200)

(220)

(111)

(200)(220)

M － Crystal orientation coefficient ；I(hkl) － Measured value of the (hkl) plane diffraction peaks ；I0(hkl) － Standard value of the (hkl) plane diffraction

peaks in PDF card ；

Crystal Orientation Discussion

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

0 2 4 6 8 10 12 14

Magnetic Flux Density/T

Ori

enta

tion

Coe

ffic

ient

(111)

(200)

(220)

Effect of MFD on Crystal Orientation Coefficient

EDS analysis of the samples electrodeposited in different magnetic fields

(Fe wt%= 0T-12.71%; 6T-14.99%; 10T-23.32%; 12T-26.10%.)

0T 6T

10T 12T

The relation between saturation magnetization

of the samples and preparation magnetic flux density

40

50

60

70

80

90

100

110

120

0 2 4 6 8 10 12 14

B/T

Ms/

emu/

g

Effect of magnetic field on electrodeposited Ni-Fe membrane

When B//I

B

I

B//I

Magnetic Field Center

SEM pictures of the surface of NiFe membrane

electrodeposited in parallel magnetic fields(J=4A/dm2)

0T 4T 6T

8T 10T 12T

6T0T

SEM pictures of the across-section of NiFe membrane electrodeposited in parallel magnetic fields (J=4A/dm2)

10T 12T

4T

8T

BJ

XRD patterns of the NiFe membranes

electrodeposited in different static magnetic fields

(Strength ratio of three main peaks ： I(111):I(200):I(220)= (0T)100:41.1:4.5; (6T)100:25.8:6.6; (10T)100:27.2:7.6; (12T)100:26.1:7.4)

0.00.2

0.40.60.8

1.01.2

1.41.6

0 2 4 6 8 10 12 14

Magnetic Flux Density/T

Orie

ntat

ion

Coe

ffici

ent (111)

(200)

(220)

Analysis of crystal orientation coefficient of the samples

EDS analysis of the samples

electrodeposited in different magnetic fields

(Fe wt%= 0T-14.13%; 6T-14.12%; 10T-15.17%; 12T-14.47%.)

0T 6T

10T 12T

The relation between saturation magnetization

of the samples and preparation magnetic field

0T

10T

SEM pictures of the surface of NiFe membrane electrodeposited without magnetic field

(J= a-1A/dm2; b-2A/dm2; c-3A/dm2; d-4A/dm2; e-6A/dm2)

a b c

d e

a b c

d e

FSEM pictures of the across-section of NiFe membrane

electrodeposited without magnetic field

(J= a-1A/dm2; b-2A/dm2; c-4A/dm2; d-5A/dm2; e-6A/dm2)

Fig.17-a SEM pictures of the surface of NiFe membrane

electrodeposited in 10T static magnetic field

(J= a-1A/dm2; b-2A/dm2; c-3A/dm2; d-4A/dm2; e-5A/dm2; f-6A/dm2)

a b c

d e f

a b

c d

SEM pictures of the across-section of NiFe membrane

electrodeposited in 10T static magnetic field

(J= a-2A/dm2; b-3A/dm2; c-4A/dm2; d-6A/dm2)

(a) 0T (b) B1(B1≠0T) B2(B2≥10T)

Hydration Ions Metal atom

Metal Crystal

Sphere Crystal nucleus

FL

IBFE

Outer Helmholtz area

Bulk solution

Trajectory of Ions

Boundary LayerTrajectory of Ions

Sketch Map of Nucleation and Crystal Growth when B⊥I

In Homogeneous Magnetic Field

Initial velocity (v0)

BubbleDirection of electric field (I)

Direction of magnetic field (B)

Cathode

Anode

Sketch Map of Nucleation and and Crystal Growth when B//I

In Homogeneous Magnetic Field

Magnetic field

Migration of atoms in Horizontal direction

Electro-depostion of NiFe Membrane in Gradient Magnetic Field

+400T2/m 0 -400T2/m

 Magnetic Field Gradient

Element Wt % At%

+400T2/mFeK 38.37 39.56

NiK 61.63 60.44

0T2/mFeK 22.84 23.73

NiK 77.16 76.27

+400T2/mFeK 29.39 30.44

NiK 70.61 69.56

B

I

B//I

B

J

Sketch Map of Nucleation and and Crystal Growth when B//I and in Gradient Magnetic Field

Conclusions

In HSMF, Strengthened MHD effect may influence the crystal morphology of electrodeposited NiFe membrane remarkably, so do the mass transfer process;

Both perpendicular and parallel magnetic field can make the crystal (111) plane texture reinforced;

The iron contents and the saturation magnetization were increased in perpendicular magnetic field but unchanged in parallel one .

Thank you

for your attentions!