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, Shanghai University

2nd Sino-German Workshop on EPM, October, 16-19, 2005, Dresden, Germany

Outline Motivation; Experimental Apparatus; Results and Discussion; Conclusion and Outlook; Acknowledgement;

Influence on electron transfer kinetics ?

Influence on mass transportMHD effect

Influence on Surface Diffusion 、 Necleation 、Crystal Growth?

1.MotivationElectro-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

Ni2+ : Paramagnetism ;

Fe2+ : Diamagnetism;

Ni atom: Paramagnetism;

Fe atom: Paramagnetism;

Ni Crystal: Ferromagnetism;

Fe Crystal: Ferromagnetism;

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

2.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

MFD

, 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 MFD in High Static Magnetic Field

Homogeneous MF Upper Gradient MF

Lower Gradient MF

Effect of HSMF on electrodeposited Ni-Fe membrane When I⊥B

B

IMagnetic Field

Center

Ni2+: 1.2mol/l;

Fe2+: 0.07mol/l

pH=3.5;

J=4.0A/dm2

3.Results and Discussion

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

Intensity 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)

0.0

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

Orie

ntat

ion

Coe

ffic

ient (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 intensity

of the samples and preparation magnetic field

Effect of magnetic field on electrodeposited Ni-Fe membrane When

B//I Without Bubble Agitation and at Room Temperature

B

I

B//I

Magnetic Field Center

0T

10T

Electro-depostion of NiFe Membrane in Gradient Magnetic Field (B//I)

+400T2/m 0 -400T2/m

J=0.3A/cm2

Room Temperature, No Agitation

 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

(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

Discussion

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

B

I

B//I

B

J

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

Room Temperature, No Agitation

Interpret for the Composition-Change of Electrodeposited Ni-Fe Membrane in HSMF

B

I

B//I

BdB/dzFe2+ Rich

Fe2+ Rich

Stable area

B

I

I

B J⊥

Agitation

Homo. MF

B//J

Agitation

Homo. MF

B//J

No Agitation

Gradient MF

z

4.Elementary Conclusions

In HSMF, Strengthened MHD effect can 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 orientation reinforced;

The ion concentration in electrolyte would be changed due to different magnetism property of ions in gradient HSMF, which would effect the composition of deposit;

The superimposition of HSMF would affect the nucleation of electro-crystallization process;

The saturation magnetization of Ni-Fe membrane was determined mainly by the concentration of iron.

Outlook

There are a lot of questions need to be made clear: Will HSMF change the electron transfer process? Simulation on the nucleation of crystal when electro-

deposition in HSMF; The magnetic susceptibility (x) Value of ions in electrolyte; Can we control the structure even the property of membrane? …………To answer those questions, maybe we can collaboration with

Germany Part and Chinese Part!

5.Acknowledgement

This work was financial supported by Shanghai Scientific & Technological Committee (Key Project No. 03JC14029);

Thankful to Sino-German Center for Research Promotion to Support this Workshop;

Thankful to Dr. Gerbeth for well organization!

Thank you

for your attentions!

Effect of magnetic field on electrodeposited Ni-Fe membrane

When I⊥B

B

IMagnetic Field

Center

Ni2+: 1.2mol/l;

Fe2+: 0.07mol/l

pH=3.5;

J=4.0A/dm2

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)