1. Yunbo Zhong, Li Zhihua, Zhongming Ren Shanghai University
Preparation of Nano Ferrite Particle by Chemical Way in High Static Magnetic Field(HSMF)
Yunbo Zhong, Li Zhihua, Zhongming Ren
Shanghai University

2. Process of Material in HSMF
Metallic Material
Nano-Material
HSMF
Inorganic Non-metallic Material
Organic or Biological Material

3. 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…………

4. Several Questions About Preparation of Nano Material by Chemical Way in HSMF
Will Magnetic Field Effect the Process of Chemical Reaction?
Will Magnetic Field Effect the Process of Sediment/nucleation of Nano Particle?
Will Magnetic Field Effect the Growth of the Nano Particle?
Will Magnetic Field Effect the Performance of Nano Material?

5. 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;

6. Equipment for Experiment
Nitrogen
Mixture of Iron Nitrate, Manganese Nitrate and Zinc Nitrate Solution
Ammonia
Thermocouple
PID Temperature
Controller
Water-cooling Pipe
Superconductive Coil
Heater
Buffer
Solution
Heat Resistant Fibre
Quartz Pipe
Superconductive Magnet
pH Meter
pH Probe

7. High Static Magnetic Field
Distribution of MFD in
High Static Magnetic Field

8. Flow Chart of Experimental
Co-Precipitation
Filtration
Abstersion
Drying
SEM、TEM
(Fe、Mn、Zn)NO3 Mixture
NH4HCO3 Solution
Ammonia Liquid
Control pH

9. 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

10. Effect of temp. on Shape of sediment
40℃
50℃
60℃
70℃
B=10T、Adding time of reactant solution=6hrs、pH＝7～8

11. In Aqueous Solution, the Critical radius of New Nucleus is
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;

12. 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

13. 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

14. Effect of MFD on Shape of sediment
B=4T
B=10T
Temp＝80 ℃；t＝6h；PH＝7～9

15. Sketch map of the mechanism of effect of Magnetic Field on nucleation and growth of nano-particle
Solution
Aggregate Particle
Claviform Particle
Without magnetic field
Critical magnetic field
High static magnetic field

16. Energy spectrum analysis of sedimentb c d

17. Composition of Particles
Iron
Atomic %
Maganese
Zinc
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
22.91
5.08
0.66
4.51
34.71

18. X-ray diffraction spectrum

19. Main Phase Composition of Particle
Zinc Ferrite
Manganese Trioxide
Iron Trioxide
10T
None
Manganese Tetroxide
Iron Tetroxide 0T
Zinc
Manganese
Iron

20. TEM Image of Non-Claviform Particle
Bright Image
Dark Image
Electron Diffraction Image

21. TEM Image of Claviform Particle

22. Performance Measurement
Next Step Work
Fibre Nano Particle
Alignment in HSMF
Sintering
Performance Measurement

23. Conclusions
HSMF will effect the nucleation of chemical sediment process, and there is a critical MFD, Above which the nucleation will grow into stick-like or fibre-like;
The claviform particle by HSMF shows the structure of crystal, while the polygonal particle is the mixture of non crystal and crystal;
The HSMF will not only effect the shape of sediment, but also the phase composition;

24. 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

25. Thank you for your attention