Effect of HSMF on Electrodeposited Ni-FeMembrane-- Crystal Morphology andMagnetism Performance
Yunbo Zhong, Yanling Wen, ZhongmingRen, 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 electrontransfer kinetics ?
Influence on mass transport
MHD effect
Influence on SurfaceDiffusion、Necleation、Crystal Growth?
1.Motivation
Electro-Crystallization in HSMF
H2O
Me2+
Metal
Membrane
E0
Charge
Transfer
Surface
Diffusion
Nucleation
Crystal
Growth
Bulk
Solution
Boundary
Layer
Variation of Free Energy in the processof Electro-deposition of NiFe membrane
The χ data is very lacking, and the magnetism of ionsin solution are not very clear
Ni2+ : Paramagnetism ;
Fe2+ : Diamagnetism;
Ni atom: Paramagnetism;
Fe atom: Paramagnetism;
Ni Crystal: Ferromagnetism;
Fe Crystal: Ferromagnetism;
PID Temperature
Controller
B
I
B⊥I
B
I
B//I
Magnetic
Field Center
Nitrogen
Thermocouple
Water-cooling Pipe
Supercon-ductive Coil
Heater
Electrolyte
Heat Insulator
Quartz Pipe
Electrode
B
+
-
Fix Block
2.Experimental Equipment
NickelPlate
CopperFoil
Distribution of MFD in High StaticMagnetic Field
Homogeneous MF
Upper Gradient MF
Lower Gradient MF
Effect of HSMF on electrodepositedNi-Fe membrane When I⊥B
B
I
Magnetic FieldCenter
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
12T
10T
B
XRD patterns of the NiFe membranes
electrodeposited in different magnetic flux density
Intensity ratio of threemain 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
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
Effect of magnetic field on electrodepositedNi-Fe membrane When B//I
B
I
B//I
Magnetic FieldCenter
SEM pictures of the surface of NiFe membrane
electrodeposited in parallel magnetic fields(J=4A/dm2)
0T
4T
6T
8T
10T
12T
6T
0T
SEM pictures of the across-section of NiFe membraneelectrodeposited in parallel magnetic fields (J=4A/dm2)
10T
12T
4T
8T
B
J
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)
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 BubbleAgitation and at Room Temperature
B
I
B//I
Magnetic FieldCenter
0T
10T
Electro-depostion of NiFe Membrane inGradient Magnetic Field (B//I)
+400T2/m
0
-400T2/m
J=0.3A/cm2
Room Temperature, No Agitation
Magnetic FieldGradient
Element
Wt %
At%
+400T2/m
FeK
38.37
39.56
NiK
61.63
60.44
0T2/m
FeK
22.84
23.73
NiK
77.16
76.27
+400T2/m
FeK
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
I
B
FE
Outer Helmholtz area
Bulk solution
Trajectory of Ions
Boundary Layer
Trajectory of Ions
Sketch Map of Nucleation and Crystal Growth when B⊥I
In Homogeneous Magnetic Field
Discussion
Initial velocity (v0)
Bubble
Direction 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 inHorizontal direction
B
I
B//I
B
J
Sketch Map of Nucleation and and Crystal Growthwhen B//I and in Gradient Magnetic Field
Room Temperature, No Agitation
Interpret for the Composition-Change ofElectrodeposited Ni-Fe Membrane in HSMF
B
I
B//I
BdB/dz
Fe2+ 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 crystalmorphology of electrodeposited NiFe membrane remarkably,so do the mass transfer process;
Both perpendicular and parallel magnetic field can make thecrystal (111) plane orientation reinforced;
The ion concentration in electrolyte would be changed due todifferent magnetism property of ions in gradient HSMF,which would effect the composition of deposit;
The superimposition of HSMF would affect the nucleation ofelectro-crystallization process;
The saturation magnetization of Ni-Fe membrane wasdetermined 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 withGermany Part and Chinese Part!
5.Acknowledgement
This work was financial supported by ShanghaiScientific & Technological Committee (Key Project No.03JC14029);
Thankful to Sino-German Center for ResearchPromotion to Support this Workshop;
Thankful to Dr. Gerbeth for well organization!
Effect of magnetic field on electrodepositedNi-Fe membrane When I⊥B
B
I
Magnetic FieldCenter
Ni2+: 1.2mol/l;
Fe2+: 0.07mol/l
pH=3.5;
J=4.0A/dm2
SEM pictures of the surface of NiFe membrane electrodepositedwithout 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)