Upload
lythu
View
224
Download
0
Embed Size (px)
Citation preview
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
FABRICATION OF STRONTIUM FERRITE
MAGNETIC MATERIAL THROUGH WET
PROCESSING
Thesis submitted in accordance with the partial requirements of the
Universiti Teknikal Malaysia Melaka for the Bachelor
Of Manufacturing Engineering (Engineering Materials) with Honours
By
Nik Norzaliza binti Long Hassan
Faculty of Manufacturing Engineering
May 2008
UTeM Library (Pind.1/2007)
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
BORANG PENGESAHAN STATUS LAPORAN*
JUDUL: Fabrication of Strontium Ferrite Magnetic Material through Wet
Processing.
SESI PENGAJIAN: 2007/2008
Saya Nik Norzaliza Binti Long Hassan
mengaku membenarkan tesis (PSM/Sarjana/Doktor Falsafah) ini disimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut:
1. Tesis adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis.2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan untuk tujuan pengajian sahaja dengan izin penulis.3. Perpustakaan dibenarkan membuat salinan tesis ini sebagai bahan pertukaran antara institusi pengajian tinggi.4. **Sila tandakan (√)
SULIT
TERHAD
TIDAK TERHAD
(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia yang termaktub di dalam AKTA
RAHSIA RASMI 1972)
(Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan)
(TANDATANGAN PENULIS)
Alamat Tetap: Lot 506, Kampong Kemasin, Perupok,
16300 Bachok, kelantan
Tarikh: _______________________
Disahkan oleh:
(TANDATANGAN PENYELIA)
Cop Rasmi:
Tarikh: _______________________
** Jika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT atau TERHAD.
FAKULTI KEJURUTERAAN PEMBUATAN
Rujukan Kami (Our Ref) : 20 Mei 2008Rujukan Tuan (Your Ref):
Pustakawan Perpustakawan Universiti Teknikal Malaysia MelakaUTeM, No 1, Jalan TU 43, Taman Tasik Utama, Hang Tuah Jaya, Ayer Keroh, 75450, Melaka
Saudara,
PENGKELASAN TESIS SEBAGAI SULIT/TERHAD- TESIS SARJANA MUDA KEJURUTERAAN PEMBUATAN (Department of Materials Engineering): Nik Norzaliza Binti Long Hassan.TAJUK: Fabrication of Strontium Ferrite Magnetic Material through Wet Processing.
Sukacita dimaklumkan bahawa tesis yang tersebut di atas bertajuk “Fabrication of Strontium Ferrite Magnetic Material through Wet Processing” mohon dikelaskan sebagai terhad untuk tempoh lima (5) tahun dari tarikh surat ini memandangkan ia mempunyai nilai dan potensi untuk dikomersialkan di masa hadapan.
Sekian dimaklumkan. Terima kasih.
“BERKHIDMAT UNTUK NEGARA KERANA ALLAH”
Yang benar,
.........................DR AZIZAH SHAABANPensyarah, Fakulti Kejuruteraan Pembuatan (Penyelia Bersama)No telefon: 06-2332122Email : [email protected]
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
Karung Berkunci 1200, Ayer Keroh, 75450 Melaka
Tel: 06-233 2421, Faks : 06 233 2414 Email: [email protected]
DECLARATION
I hereby declare that this report entitled FABRICATION OF STRONTIUM FERRITE
MAGNETIC MATERIAL THROUGH WET PROCESSING is the result of my own
research except as cited in the references.
Signature : ……………………………………Author’s Name : Nik Norzaliza Binti Long HassanDate : 20.05.2008
ii
APPROVAL
This report is submitted to the Faculty of Manufacturing Engineering of UTeM as a
partial fulfillment of the requirements for the degree of Bachelor of Manufacturing
Engineering (material engineering). The members of the supervisory committee are as
follow:
…………………………..
Dr Azizah Shaaban (Main Supervisor)
iii
ABSTRACT
The purpose of doing this project is to evaluate the phase composition for
calcined ferrite using SEM-EDX and XRD and to evaluate microstructure effects on
calcined materials. The raw material used in this study is strontium ferrite which is
combination between strontium carbonate and iron oxide. The material was mill and
mixed with ethanol during ball milling process. The next process continues with
calcined in 12500C of temperature and followed by crushing process. First sample is
sintered at 12500C and second sample sintered at 12700C. Then the calcined powder is
mixed by using 2 different percentages of Nickel using Tambling mixing. Third sample
consist of 1% of Nickel and 99% of calcined powder and fourth sample is consisting 2%
of Nickel and 98% of calcined powder. Both of third and fourth samples are sintered at
12700C. The grains size of ferrite is analysis with Scanning Electron Microscope (SEM)/
EDX and XRD. Backscattered image is carried out from the EDX to evaluate the
chemical analysis and morphology. Physical analysis of the sample is carried out using
Electronic densimeter to measure the density. The main phase compositions in calcined
powder are strontium ferrite and Fe2O3. SEM indicated that a continuous network of
pores exist in the microstructure make the value of density low. Besides, it could be
observed that there were small amount of Nickel on the surface of grains boundaries.
Addition of Nickel as additive strongly affects the structural and morphological of the
samples.
iv
ABSTRAK
Projek ini adalah bertujuan untuk menilai komposisi fasa pengkalsinan ferrite
dengan menggunakan SEM-EDX dan XRD dan untuk menilai kesan pengkalsinan ke
atas struktur mikro bahan. Bahan mentah yang di gunakan dalam kajian ini ialah
strontium ferrite di mana terhasil daripada kombinasi antara strontium carbonate dan
iron oxide. Bahan ini mesti di kisar dan dicampur dengan ethanol semasa proses
pengisar bebola. Proses di ikuti dengan pengkalsian pada suhu 12500C dan seterusnya
dengan proses penggempuran. Sampel pertama disinter pada 12500C dan sampel kedua
disinter pada suhu 12700C. Kemudian bahan pengkalsinan di campur dengan dua jenis
peratusan Nikel yang berbeza secara ‘tambling’. Sampel ketiga terdiri daripada 1%
Níkel dan 99% serbuk pengkalsinan. Sampel keempat pula terdiri daripada 2% Nickel
dan 98% serbuk pengkalsinan. Sampel ketiga dan keemapat kemudiaanya di sinter pada
suhu 12700C. Saiz butiran ferit di analisis dengan mengunakan Scanning Electron
Microscope (SEM)/ EDX dan XRD. Imej backscattered dilakukan dengan EDX untuk
manjalankan analisis kimia dan morfologi. Analisis fizik sampel dijalankan
menggunakan Elektronik densimeter untuk mengukur ketumpatan. Fasa utama yang
terdapat dalam serbuk pengkalsinan adalah stontium feritte dan Fe2O3. SEM
menunjukkan rangkaian liang-liang yang wujud dalam mikrostruktur menyebabkan nilai
ketumpatan menjadi rendah. Selain itu, boleh diperhatikan terdapat unsur Nikel di
permukaan sempadan butir tapi hanya dalam jumlah yang kecil. Secara jelasnya
penambahan Nikel sebagai bahan tambahan dalam serbuk pengkalsinan menjejaskan
struktur dan mofologikal sampel.
v
ACKNOWLEDGEMENT
I would like to express my appreciation to the individuals who had played a part
in ensuring a successful occurrence and flow of activities throughout the duration of my
final year project. Endless appreciation and gratitude to my supervisor, Dr Azizah
Shaaban and to my first panel Dr Warikh for their encouragement and support and for
spending quite some time with myself, providing a lot of guidance and ideas for my
project research. Their knowledge and experience really inspired and spurred myself. I
truly relished the opportunity given in working with them. Last but not least, my
appreciation to Mr. Mohd Azhar Shah b. Abu Hassan , Mr. Hairulhisham b. Rosnanm Mr
Mahader bin Muhamad, Mr Sarman and all technicians involved to complete this project.
Finally, my sincere appreciation is dedicated to my parents and family and as well as the
friends for their priceless assistance and patronage throughout the process of data
gathering.
vi
TABLE OF CONTENT
DECLARATION iiAPPROVAL iiiABSTRACT ivABSTRAK vACKNOWLEDGEMENT viTABLE OF CONTENTS viiLIST OF FIGURES xiLIST OF TABLES xvLIST OF ABBREVIATIONS, SYMBOLS,
SPECIALIZED NOMENCLATURES
xvi
CHAPTER 1 INTRODUCTION1.1 Background of the project 11.2 Problem Statement 11.3 Objectives 21.3 Introduction on Magnetic material 2
1.4.1 Ceramic material 21.4.2 Ceramic magnet 31.4.3 Properties of magnetic material 41.4.4 Application of magnetic material 6
CHAPTER 2 LITERATURE REVIEW2.1 Type of magnetism 7
2.1.1 Diamagnetism 72.1.2 Paramagnetism 82.1.3 Antiferromagnetism 82.1.4 Ferrimagnetism 82.1.5 Ferromagnetism 92.2 Type of ferrites 102.2.1 Hard ferrite 112.2.2 Soft ferrite 122.2.3 Other type of magnetic materials 12
2.3 Starting material for strontium ferrite 15 2.3.1 Strontium carbonate 15
vii
2.3.2 Iron oxide 15 2.3.3 Ethanol 16 2.3.4 Nickel 162.4 Previous research on strontium ferrite 17
2.4.1 Process parameter selection for strontium
ferrite sintered magnets using Taguchi L9
orthogonal design.
17
2.4.2Barium and Strontium ferrite perpendicular
thin film media with a sendust soft
magnetic underlayer.
18
2.4.3Fine powders of SrFe12O19 with SrTiO3
additive prepared via a quasi-dry
combustion synthesis route
19
2.4.4 Microstructure of pre-sintered
permanent magnetic strontium ferrite
powder
19
CHAPTER 3 METHODOLOGY3.1 Powder processing 21
3.1.1 Milling and mixing 223.1.2 Calcinations 243.1.3 Crushing 253.1.4 Sieving 253.1.5 Mixing 263.1.6 Compact 263.1.7 Sintering 28
3.2 Sample Characterization 28 3.2.1 Sample preparation for microstructure
evaluation
28
3.2.2 Microstructure evaluation 303.2.1.2 Optical microscope 303.2.1.2 Scanning Electron Machine
(SEM)
32
3.2.3 Phase analysis 343.2.4 Density measurement 35
viii
CHAPTER 4 RESULT AND DISCUSION4.1 Observation on powder 37 4.1.1 As-received material 37
4.1.1.1 Iron Oxide 374.1.1.2 Strontium carbonate 384.1.2 Milled powder 39
4.1.3 Calcined powder 404.2 Composition Study on Strontium Ferrite 414.3 Sintered Strontium Ferrite 43
4.3.1 Final Specimens 444.3.2 Optical Observation
4.3.3 SEM observation
45
4.3.3.1 Strontium ferrite sinter at 1250oC 464.3.3.2 Strontium ferrite sinter at 1270oC 484.3.3.3 Strontium ferrite + 1% Nickel
sintered at 1270oC
49
4.3.3.4 Strontium ferrite + 2% Nickel
sintered at 1270oC
50
4.3.4 EDX microstructure4.3.3.2 Strontium ferrite sinter at 1270oC 514.3.3.3 Strontium ferrite + 1% Nickel
sintered at 1270oC
52
4.3.3.4 Strontium ferrite + 2% Nickel
sintered at 1270oC
53
4.3.5 Phase analysis 54 4. 3.6 Physical properties 56
4.3.6.1 Mass and Volume measurement 574.3.6.2 Density measurement 57
4.4 Defect on sample 58
CHAPTER 5 CONCLUSION AND RECOMMENDATION 60REFERENCES 62APPENDIX A 65APPENDIX B 67APPENDIX C 69APPENDIX D 71APPENDIX E 71
ix
LIST OF FIGURES
Figure 1.1(a) Ceramic Blocks 3
Figure 1.1(b) Ceramic Discs 3
Figure 1.1(c) Ceramic Rings 3
Figure 1.2 Generic hysteretic plot of magnetization as a
function of magnetic material. 5
Figure 2.1 Ferrite magnet 11
Figure 3.1 Processing Flow 21
Figure 3.2 Ball milling machine 23
Figure 3.2.1(a) mixing process 24
Figure 3.2.1(b) filtration 24
Figure 3.2.1(c) Powder after filtration and drying 24
Figure 3.3(a) Powder in aluminum bowl 25
Figure 3.3(b) Furnace 25
Figure 3.4 Alumina mortar 25
Figure 3.6(a) Oil strainer 26
Figure 3.5(b) Oil strainer observation by Axioscope using 26
10x magnification.
Figure 3.6 Tambling mixing 27
xi
Figure 3.7 Hydraulic Press Machine 27
Figure 3.8 Sintering profile 28
Figure 3.9 Diamond cutter 29
Figure 3.10 Figure shows steps for sample preparation. Figure 30
shows sinter specimens; (a) grinding and (b) etching
Figure 3.11(a) Optical microscope 31
Figure 3.11(b) Schematic diagram of the optical micrograph 31
Figure 3.12(a) SEM component 33
Figure 3.12(b) SEM operating 33
Figure 3.13 Electronic Densimeter 35
Figure 4.1 Figure shows SEM image for as-received Iron oxide 37
with different magnification; (a) 500x (b) 2500x.
Figure 4.2 Figure shows SEM image for as-received 38
Strontium carbonate with different magnification;
(a) 500x (b) 2500x.
Figure 4.3 Figure shows SEM image of Strontium ferrite after 39
milled with different magnification; (a) 500x (b) 2500x
Figure 4.4 SEM image of strontium ferrite powder after 40
calcined; (a) particles size (b) microstructure
with 2500 x magnification. Yellow circle indicates
powder agglomeration.
Figure 4.5 XRD patterns of strontium ferrite calcined 41
xii
at.1250oC 50C/min
Figure 4.6 Figure shows for all specimens after mounting; 44
(a) Strontium ferrite + 1% Ni sinter at 1270,
(b) Strontium ferrite sinter at 1270,
(c) Strontium ferrite + 2% Ni sinter at 1270,
(d) Strontium ferrite sinter at 1250
Figure 4.7 All figure shows the observation using optical 45
microscopy using 20 X magnification
(a) Strontium ferrite sinter at 1250
(b) Strontium ferrite sinter at 1270 oC
Figure 4.8 Figure shows SEM image for Strontium ferrite 47
sintered at 1250oC with different magnification
(a) 800x (b) 1500x (c) 5000x.
Figure 4.9 Figure shows SEM image for Strontium ferrite 48
sintered at 1270 oC with different magnification;
(a) 1500x ( b) 2500x (c) 5000x.
Figure 4.10 Figure shows SEM image for Strontium ferrite + 49
1% Nickel sintered at 1270 oC with different
magnification; (a)1500x (b) 2500x (c) 5000x.
Figure 4.11 Figure shows SEM image for Strontium ferrite + 50
2% Nickel sintered at 1270 oC with different
magnification; (a)1500x (b) 2500x (c) 5000x.
Figure 4.12 EDX result for Strontium ferrite sinter at 1270 oC 51
xiii
Figure 4.13 EDX result of Strontium ferrite + 1% Nickel 52
sintered at 1270 oC
Figure 4.14 EDX result of Strontium ferrite + 2% Nickel 53
sintered at 1270 oC
Figure 4.3.15(a) SEM Backscattered image of strontium ferrite 54
sintered at 1270 without nickel with 2500 x magnification.
Figure 4.3.15(b) SEM Backscattered image of strontium ferrite + 55
1 % Nickel sintered at 1270 oC with 2500 x magnification
Figure 4.3.15(c) SEM Backscattered image of strontium ferrite + 56
2 % Nickel sintered at 1270 oC with 2500 x magnification.
Figure 4.16(a) Specimen after sinter at 1250oC 58
Figure 4.16(b) Strontium ferrite sinter at 1270 oC 58
Figure 4.16(c) Strontium ferrite + 1% Nickel sinter at 1270oC 58
Figure 4.16(d) Strontium ferrite + 2% Nickel sinter at 1270oC 58
xiv
LIST OF TABLES
Table 1.1 Typical Magnetic and Physical Properties
of ferrite Magnet Material 5
Table 2.1 Magnetic Material Classification 7
Table 2.2 Summary of different types of magnetic behavior 9
Table 2.3 Physical Properties of hard ferrite 12
Table 2.4 Selected process parameters and their respective
levels in the present experimental design. 18
Table 4.1 Data of mass and volume 57
Table 4.2 Data of Density measurements 57
xv
LIST OF ABBREVIATIONS, SYMBOLS, NOMENCLATURES
SEM - Scanning Electron MachineEDX - Energy Dispersive X-ray AnalysisXRD - X-ray diffraction
xvi
CHAPTER 1
INTRODUCTION
1.1 Background of the project
The fabrication of the strontium ferrite magnetic material through wet
processing is doing by mixing the strontium carbonate with iron oxide powder in
wet milling. Wet milling is the grinding of materials with sufficient liquid to form
slurry. The mixing of both as received powder is doing in ball mill machine and
then calcined at certain temperature. The calcined powder is mix with the different
percentage of additives and then sintered at certain temperature. The
microstructure effect and the phase composition of the samples are evaluated using
SEM-EDX and XRD.
1.2 Problem statement
The objectives of this project are to evaluate microstructure effect and the
phase composition of the samples using SEM-EDX and XRD. The interaction of
Nickel powder as additive material in calcined material influence the grains size of the
sample after sintered. This evaluation will focus on three areas. First, microstructure
evaluation using SEM-EDX and phase analysis by XRD. Second, the percentages of
nickel powder as additives and the effect of the percentage of additives material on the
grains size of sintered samples. Lastly, the effect of different sintered temperature to
density value.
1
1.3 Objectives
The objectives of this project are:
i. To evaluate the phase composition for calcined ferrite using SEM-EDX
and XRD
ii. To evaluate microstructure effects on calcined materials.
1.4 Introduction on Magnetic material
Materials may be classified according to some of their basic magnetic properties,
particularly whether or not it is magnetic and how behave in the vicinity of an external
magnetic field. When a material is placed within a magnetic field, the magnetic forces of
the material's electrons will be affected. This effect is known as Faraday's Law of
Magnetic Induction. However, materials can react quite differently to the presence of an
external magnetic field. This reaction is dependent on a number of factors, such as the
atomic and molecular structure of the material, and the net magnetic field associated with
the atoms. The magnetic moments associated with atoms have three origins. These are
the electron orbital motion, the change in orbital caused by an external magnetic field and
the spin of the electrons. In most atoms, electrons occur in pairs. Electrons in a pair spin
in opposite directions. So, when electrons are paired together, their opposite spins cause
their magnetic fields to cancel each other. Therefore, no net magnetic field exists.
Alternately, materials with some unpaired electrons will have a net magnetic field and
will react more to an external field
1.4.1 Ceramic material
Ceramics is a singular noun referring to the art of making things out of ceramic
materials. The technology of manufacturing and usage of ceramic materials is part of the
field of ceramic engineering. Many ceramic materials are hard, porous and brittle.
Ceramic materials are usually ionic or covalently-bonded materials, and can be
crystalline or amorphous. A material held together by either type of bond will tend to
2
fracture before any plastic deformation takes place, which results in poor toughness in
these materials. Additionally, because these materials tend to be porous, the pores and
other microscopic imperfections act as stress concentrators, decreasing the toughness
further, and reducing the tensile strength. These combine to give catastrophic failures, as
opposed to the normally much more gentle failure modes of metals. These materials do
show plastic deformation. However, due to the rigid structure of the crystalline materials,
there are very few available slip systems for dislocations to move, and so they deform
very slowly. With the non-crystalline (glassy) materials, viscous flow is the dominant
source of plastic deformation, and is also very slow. It is therefore neglected in many
applications of ceramic materials.
1.4.2 Ceramic magnet
Ferrite magnets are combination between strontium, barium or plumbum
carbonate and iron oxide. They are charcoal gray in color and usually appear in the forms
of discs, rings, blocks, cylinders, and sometimes arcs for motors. Figure 1.1(a), (b) and
(c) below are the type of form of ceramic magnetic.
Figure 1.1(a): Ceramic Blocks
Figure 1.1(b): Ceramic Discs
3
Figure 1.1(c): Ceramic Rings
Sources: http://www.allmagnetics.com/ceramic.htm
Attributes of Ceramic Magnets:
• High intrinsic coercive force
• Tooling is expensive
• Least expensive material compared to alnico and rare earth magnets
• Limited to simple shapes due to manufacturing process
• Lower service temperature than alnico, greater than rare earth
• Finishing requires diamond cutting or grinding wheel
• Lower energy product than alnico and rare earth magnets
• Most common grades of ceramic are 1, 5 and 8 (1-8 possible)
• Ceramic grade 8 shown in Table 1.1 is the strongest ceramic material available.
1.4.3 Properties of magnetic material.
When ferromagnetic materials are magnetized, demagnetized, and re-magnetized,
they exhibit a hysteretic behavior illustrated as shown in Figure 1.2. Important and often
quoted features of these graphs are the saturation magnetization Ms, remanent
magnetization Mr, coercivity Hc, and saturating field Hs. With these parameters,
ferromagnetic materials can be divided into so-called soft magnetic materials (i.e., with a
small coercivity and low saturation field) and hard magnetic materials (i.e., with a large
coercivity and high saturation field).
4
Figure 1.2: Generic hysteretic plot of magnetization as a function of magnetic material.
Sources: Judy and Myung (2001)
Table 1.1: Typical Magnetic and Physical Properties of ferrite Magnet Material
Magnetic
Materials
Density
Maximum
Energy
Product
BH (max)
Residual
Induction
Br
Coercive
Force
Hc
Intrinsic
Coercive
Force
Hc
Normal
Maximum
Operating
Temp.
Curie
Temp.
lbs/in g/cm MGO Gauss Oersteds Iersteds F° C° F° C°Ceramic 1 0.177 4.9 1.05 2300 1860 3250 842* 450 842 450Ceramic 5 0.177 4.9 3.4 3800 2400 2500 842* 450 842 450
Ceramic 8 0.177 4.9 3.5 3850 2950 3050 842* 450 842 450
Sources: http://www.allmagnetics.com/ceramic.htm
All magnet materials demonstrate reversible strength loss as they approach Maximum
operating temperature.
* NOTE: Unshielded open circuit ceramic magnets should not be subjected to more than
400°F.
5
1.4.4 Application of magnetic material
Applications of ferrite Magnets are Speaker magnets, DC brushless motors,
Magnetic Resonance Imaging (MRI), Magnetos used on lawnmowers and outboard
motors, DC permanent magnet motors (used in cars), Separators (separate ferrous
material from non-ferrous), Used in magnetic assemblies designed for lifting, holding,
retrieving, and separating.
6
CHAPTER 2
LITERITURE REVIEW
2.1 Type of magnetism
Magnetic materials can be classified according to their magnetic susceptibility χ =
M / H and relative permeability μr = (χ / μ0 + 1) into several categories: ferromagnetic,
ferrimagnetic, antiferromagnetic, paramagnetic, diamagnetic, and superconducting
materials. Listed in Table 2.1 are the typical ranges of χ / μ0 for each category of
magnetic material and examples of each are identified (Parker 1989).
Table 2.1: Magnetic Material Classification
Category χ/μ0 ExamplesFerromagnetic 107 to 102 Ni, Fe, Co, NiFe, NdFeBFerrimagnetic 107 to 101 Fe3O4 Ferrite, garnetsAntiferromagnetic small MnO, NiO, FeCO3Paramagnet 10-3 to 10-6 Al, Cr, Mn, Pt, Ta, Ti, WDiamagnetic 10-6 to -10-3 -Ag, Au, C, H, Cu, Si, ZnSources from Parker(1989)
2.1.1 Diamagnetism
If the net magnetic moment of each atom in a material is zero because of mutually
canceling electronic movement within the atom, then the net flux density within the
material, due to an applied external field, is slightly less than i t would be in space
for the same field. Such a material is term diamagnetic. Examples are Cu, Bi, Pb and Ga.
Bismuth is the most pronounced diamagnetic element known (Parker 1989).
2.1.2 Paramagnetism
7