91 ISSN 2086-5953
STRUCTURAL TRANSITION AND MAGNETIC PROPERTIES OF ZN-DOPED FE
3
O
4
BY CO-PRECIPICATION METHOD
Sigit Tri Wicaksono
1
, Haizan
2 1,2
Materials and Metallurgical Engineering, FTI, ITS Jl. T.Industri Kampus ITS Sukolilo Surabaya 60111
Email: sigitmat-eng.its.ac.id
ABSTRACT
Magnetic properties of Zn-doped Fe
3
O
4
have been synthesis by using co-precipitation method at
low temperature. X-Ray diffraction result shows that the sample was crystalline structure and form
Zn
x
Fe
3-x
O
4
stoichiometry. Further refinement of diffractions data show that the crystal structure has
change from cubic to hexagonal structure and lattice volume decrease 10 times by increasing of
doping and occur . The magnetic properties of sample have also studied. The results show that
Zn
x
Fe
3-x
O
4
was exhibit ferrimagnetic characteristic at room temperature.
Keywords: Co-precipitation method, doping, magnetic properties.
1 INTRODUCTION
Lie and Kuo
[1]
were conduct toward the doping of ZnO into Fe3O4 to see the effect of
Fe3O4 magnetic resistance using mechanical alloying method. They succeed to exhibit the
paramagnetism phenomenon in room temperature. In pervious study we have synthesis the
manganese- based magnetic materials to exhibit the magnetic properties of Mn
3
O
4
with nano-Fe3O4 by using co-precipitation method. The results show
that sample exhibit the same condition as paramagnetism phenomenon. In this study we have
doped Fe3O4 with ZnO by the same method.
The sample
exhibit the
Zn
x
Fe
3-x
O
4
stoichiometry as shown form X-ray diffraction pattern. Further refinement of diffractions data by
using Rietica program show that there was transition phenomenon of crystal structure from
cubic to hexagonal lattice. Another phenomenon was decreasing of lattice volume 10 times by
increasing of doping. The magnetic properties of sample such as Magnetic saturation, magnetic
remanent, and coercivity have also studied. The results show that Magnetic saturation Zn
x
Fe
3-x
O
4
was decrease by increasing of doping and exhibit ferrimagnetic characteristic at room temperature.
2 EXPERIMENTAL PROCEDURE
Magnetite Fe3O4 as the parrent phase has synthezed by chemical procedure as done in
previous research
[2]
by following
chemical procedures:
3Fe3O4+8HCl
2FeCl+FeCl2+3Fe2O3+3H
₂ O+H 2.1
ZnO + 2HCl
ZnCl2
+ H2O 2.2
2FeCl2+FeCl3 + ZnCl2 + NH
4
OH
Zn
x
Fe
3-x
O
4
+ H
2
O + NH
4
Cl + H
2
+ Cl
2
2.3
3 RESULT
3.1 Structural Transition
Diffraction pattern of particles Zn
x
Fe
3- x
O
4
0x2 synthesized by co-precipitation method shown in Figure 1. Analysis of search match to
sample with the variation of x = 0 parent sample has the same diffraction pattern with diffraction
pattern Fe3O4 PDF No. 11-0614. While the sample with the variation of x = 1 has the same diffraction
pattern with diffraction pattern ZnFe2O4 PDF No. 10-0467. Final sample with the variation of x = 2
has the same diffraction pattern of ZnO PDF No. 05-0664
Figure 1. X-ray diffraction patteron of Zn
x
Fe
3-x
O
4
0x2
ISSN 2086-5953 Table 1. shows that the sample with the
variation of 0x1 have lattice length a, b, and c are nearly equal which is about 8.4 Å. While the
sample with x = 2 the lattice length a and b were the same which was about 3.25 Å and c lattice
length of about 5.2 Å. The length of the lattice parameters a, b and c are distinct form the
tetrabonal structure of spinel. The transition structure of Zn
x
Fe
3-x
O
4
from cubic to hexagonal because of the substitution of Zn ions, in which Zn
ions tend to occupy octahedral positions. The transition structure also resulted in lattice volume
decreases, because the length of a and b lattice decreased higher than the long decline in the lattice
c
[2]
Further analysis of refinement shows that the samples with cubic spinel structure variation of x =
0 which has the smallest crystal size about 99.86 nm. Samples with hexagonal spinel structure x =
2 has the largest crystal size about 32.27 nm. Crystal size difference is influenced by the radius
of the constituent ions. The radius of the ion Fe 2+, Fe3+ and Zn2+ are 7.6 Å, 7.0 Å and 6.2 Å
respectively. It can be observed that the ion radius of Zn2+ ion close to the radius of Fe 3+. This
causes Zn 2+ occupy the tetrahedral Fe3+ ion.
3.2 Magnetic Properties
According to picture 1 and its data extraction shown on table2, shows that the parent
sample x = 0 has a saturation magnetization much higher than the samples doped with ZnO x = 1 and
x = 2. The decline trend in the value of magnetization saturation of the doped sample could
theoretically occur because at this range, the value of the total magnetic moment also decreases,
especially
for sample
Zn2FeO4 saturation
magnetization caused by VSM measurements performed at room temperature, while ZnO is
diamagnetic material at room temperature.
Figure 2. Magnetization curve
Results of measurement Hc, Ms and Mr show that in general pattern of particle saturation
magnetitasi Zn
x
Fe
3-x
O
4
tend to follow the same pattern with the pattern of magnetization on the
predicted previously. Magnetic a material is closely related to
magnetic domain, domain either singular or plural domain. In general, the smaller the crystal size of a
material, the more toward a single domain state. Conversely the greater the crystal size, will be
more towards a situation plural domain. At the regional domain single-value field coercivity also
has narrowed in line with decreasing crystal size, but the crystal size that very small below the critical
size of a material which is ferro or ferrimagnetic turn into superparamagnetik.
Other magnetic properties of Zn
x
Fe
3-x
O
4
is the remanent magnetization Mr. Mr follow the
same pattern with the pattern of Ms and Hc. The greater the value of remanent magnetization, the
greater the larger the field required to eliminate them. This
happens because
the remanent
magnetization is
the amount
of residual
magnetization which is still owned by a material when it is not influenced by the external field.
4 CONCLUSION AND DISCUSSION
X-Ray diffraction result shows that the sample was crystalline structure and form Zn
x
Fe
3- x
O
4
stoichiometry. Further
refinement of
diffractions data show that the crystal structure has change from cubic to hexagonal structure and
lattice volume decrease 10 times by increasing of doping and occur . The results show that Zn
x
Fe
3-x
O
4
was exhibit ferrimagnetic characteristic at room temperature
ISSN 2086-5953
REFERENCES
[1] Lie, C.T. Kuo, P.C. 2002.
Effect doping on the magnetoresistance of sintered
Fe
3
O
4
ferrites.
Journal Magnetism and Magnetic Material.
[2]
Sigit Tri W, Darminto.2008.
Synthesis and Characterization of Nano magnetic
Mn
3-x
M
x
O
4
, 0 x 1
M= Ni,Fe,
ITS Surabaya
[3] Sunaryono, Darminto.2008.
Synthesis and
Characterization of
magneto- elastisitas hydrogel nano magnetic Fe
3
O
4
ITS Surabaya [4]
Cammarata,.Edelstein.1997.
Nanomaterials: Synthesis, Properties, and Aplications
. Institut of Physics Publishing Briston and Philadelphia.
[5]
R. W. Chantrell and K. O‘Grady, ―The magnetic properties of fine particles,‖ in
AppliedMagnetism , p. 113, Kluwer Academic
Publishers, Dordrecht, The Netherlands, 1994.
[6]
H. Ehrhardt, S. J. Campbell, and M. Hofmann, ―Magnetism ofthe nanostructured spinel zinc
ferrite,‖ Scripta Materialia, vol. 48, no. 8, pp. 1141
–1146, 2003.
[7]
C. Upadhyay, H. C. Verma, V. Sathe, and A. V.
Pimpale, ―Effect of size and synthesis route on the magnetic properties of chemically
prepared nanosize
ZnFe
2
O
4
,‖ Journal ofMagnetism and Magnetic Materials
, vol. 312, no. 2, pp. 271
–279, 2007.
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95 ISSN 2086-5953
THREE DIMENSION SIMULATION OF INJECTION-COMPRESSION MOLDING PROCESS OF DISK
Bambang Arip Dwiyantoro
1,2
, Shiu Wu Chau
1 1
Department of Mechanical Engineering, National Taiwan University of Science and Technology Taipei 10607, Taiwan, Republic of China
2
Department of Mechanical Engineering, Institute of Technology Sepuluh Nopember Surabaya, 60111, Indonesia
Email: D9603803me.ntust.edu.tw, bambangadsme.its.ac.id
ABSTRACT
Abstract should be written using Times New Roman 10, in two column format, and up to 200
words. The closer the authors stick to this guideline, the better the quaility of the proceeding
and the less the time uninterestingly spent by the organizing committee. A numerical model for the
fully three-dimensional simulation of melt filling in an injection-compression process is proposed in
this paper, where a moving grid strategy is employed. Similar to other fully three- dimensional
methods, the fully three-dimensional Navier-Stokes equations are solved together with the front
transport equation using a front capturing approach. To avoid the difficulty in specifying gas outlet
required
by SIMPLE-type
algorithms with
incoming melt, the escape of air is modeled through source terms described by a compressible model.
Filling predictions of disk part are conducted to demonstrate the advantages of proposed scheme in
simulating injection-compression processes. After conducting several computations under different
processing conditions, it was found that the compression speed and compression stroke are the
two factors affecting the molding pressure most significantly. The simulated molding pressures
were also compared with those required by conventional injection molding CIM assuming the
same entrance flow rate. Using higher switch time, lower compression speed and higher compression
stroke will result in lower cavity pressures.
Keywords: three-dimensional, moving grid, disk part, injection-compression process
1 INTRODUCTION
Injection molding, being one of most important polymer processing operations, consists
of three major stages: filling, packing, and cooling. In a pure compression molding process [1-4],
polymer melt is compressed to flow by moving the movable platen of the mold to complete melt
filling. The melt is then continued to be compressed by the pressure exerted from the mold wall of the
core side. This process provides a more uniform pressure along the cavity wal and requires only a
low molding pressure for the postfilling process. The
injection-compression molding
[1-3], combining conventional injection molding and
compression molding, has been developed to incorporate the advantages of both molding
processes. An injection-compression molding machine is constructed by modifying an injection
molding machine with an additional compression system. The compression stage is usually
introduced after partial melt filling of the cavity. Generally speaking, the injection-compression
molding process retains the advantages of conventional injection molding, such as high
production rate, steady process operation, and easy process automation. Despite of some related
researches in the injection-compression molding, the full understanding of the optimized control over
the injection-compression techniques is still far from completeness. Form the engineering point of
view, numerical tools are essential to locate the adequate processing parameters due to the
complexity of this highly nonlinear problem.
2 MODEL AND ANALYSIS
2.1 Fully Three-Dimensional Model
