Transcript Document

Preparation of Nano Ferrite Particle
by Chemical Way in High Static
Magnetic Field(HSMF)
Yunbo Zhong, Li Zhihua, Zhongming Ren
Shanghai University
Process of Material in HSMF
Metallic Material
Nano-Material
HSMF
Inorganic Nonmetallic Material
Organic or
Biological Material
Methods for Preparation of Nano-particle
1、High Energy Grinding;
2、Evaporation;
3、Co-Precipitation;
4、Sol-Gel;
5、Hydrothermal Preparation;
6、By Plasma;
And so on…………
Several Questions About Preparation
of Nano Material by Chemical Way
in HSMF
1. Will Magnetic Field Effect the Process of Chemical
Reaction?
2. Will Magnetic Field Effect the Process of
Sediment/nucleation of Nano Particle?
3. Will Magnetic Field Effect the Growth of the Nano
Particle?
4. Will Magnetic Field Effect the Performance of Nano
Material?
Why select Ferrite

Ferrite is widely used in electric
power/electron and communication industry;
 Nano ferrite material has better performance;
 In some usage, shape anisotropy of nano
ferrite will be welcome for its excellent
magnetic property;
 How magnetic field effect the chemical
reaction process is not well studied;
Equipment for Experiment
Ammonia
Nitrogen
Quartz Pipe
pH Meter
Mixture of Iron Nitrate, Manganese
Nitrate and Zinc Nitrate Solution
Thermocouple
PID Temperature
Controller
pH Probe
Buffer
Solution
Heat Resistant Fibre
Superconductive Magnet
Heater
Superconductive Coil
Water-cooling Pipe
Distribution of MFD in
High Static Magnetic Field
12
500
11
400
300
9
200
8
BdB/dz，T2 /m
，T
Magnetic Flux Density
10
7
6
5
4
100
0
-100
-200
3
2
-300
1
-400
0
-3 -2 -2 -2 -2 -2 -1 -1 -1 -1 -1 -8 -6 -4 -2
0 8 6 4 2 0 8 6 4 2 0
0
2
4
6
8 10 12 14 16 18 20 22 24 26 28 30
Distance to Center，cm
-500
-30
-20
-10
0
Distance to Center，cm
10
20
30
Flow Chart of Experimental
(Fe、Mn、Zn)NO3 Mixture
Ammonia Liquid
NH4HCO3 Solution
Control pH
Co-Precipitation
Filtration
Abstersion
Drying
SEM、TEM
B=0T、Temp=80℃、Adding time of reactant solution=1hr、pH＝7～8
B=10T、temp=80℃、Adding time of
reactant solution=6hrs、pH＝7～8
Effect of temp. on Shape of sediment
40℃
50℃
70℃
60℃
B=10T、Adding time of reactant solution=6hrs、pH＝7～8
In Aqueous Solution, the Critical radius of New Nucleus is
r
P

2
KT ln
C
C*
rp-Critical radius of New Nucleus;
σ-Surface Energy between Particle and Solution;
υ-Volume of Solution;
K- Boltzman Constant;
T-Temperature of Solution;
C-Actual Concentration of Solute;
C*-Saturation Concentration of Solute When Equilibium;
Effect of Adding time of reactant
solution on Shape of sediment
2hrs
6hrs
Adding time of reactant solution
B=10T、Temp=60℃、pH＝7～8
10hrs
Effect of MFD on Shape of sediment
B=0.3T
B=0.5T
B=0.6T
B=0.7T
Temp=60℃、Adding time of reactant solution=1h、pH＝7～8
Effect of MFD on Shape of sediment
B=4T
B=10T
Temp＝80 ℃；t＝6h；PH＝7～9
Sketch map of the mechanism of
effect of Magnetic Field on nucleation
and growth of nano-particle
Aggregate Particle
Without magnetic field
Solution
Critical magnetic field
Claviform Particle
High static
magnetic field
Energy spectrum analysis of sediment
a
b
c
d
Composition of Particles
Iron
Atomic
%
Maganese
Atomic
%
Zinc
Atomic
%
Fe:Mn
Fe:Zn
a-Claviform
Particle
14.19
17.72
1.30
0.8
10.91
b-Claviform
Particle
21.14
18.30
2.32
1.155
9.112
c-Block
Particle
22.75
5.85
0.03
3.889
758.33
d-Block
Particle
22.91
5.08
0.66
4.51
34.71
X-ray diffraction spectrum
Main Phase Composition of Particle
Iron
Manganese
Zinc
0T
Iron Tetroxide
None
10T
Iron Trioxide
Manganese
Tetroxide
Manganese
Trioxide
Zinc Ferrite
TEM Image of Non-Claviform Particle
Bright Image
Dark Image
Electron Diffraction Image
TEM Image of Claviform Particle
Next Step Work
Fibre Nano Particle
Alignment in HSMF
Sintering
Performance
Measurement
Conclusions
HSMF will effect the nucleation of chemical
sediment process, and there is a critical MFD,
Above which the nucleation will grow into sticklike or fibre-like;
2. The claviform particle by HSMF shows the
structure of crystal, while the polygonal particle
is the mixture of non crystal and crystal;
3. The HSMF will not only effect the shape of
sediment, but also the phase composition;
1.
Acknowledgement
This work was financial supported by Scientific
& Technological Committee of Shanghai;
Thankful to sino-German Center for Research
Promotion for financial support to workshop