FABRICATION OF STRONTIUM FERRITE MAGNETIC MATERIAL THROUGH WET PROCESSING

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UNIVERSITI TEKNIKAL MALAYSIA MELAKA FABRICATION OF STRONTIUM FERRITE MAGNETIC MATERIAL THROUGH WET PROCESSING Thesis submitted in accordance with the partial requirements of the Universiti

1 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

2 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) Disahkan oleh: (TANDATANGAN PENULIS) Alamat Tetap: Lot 506, Kampong Kemasin, Perupok, Bachok, kelantan (TANDATANGAN PENYELIA) Cop Rasmi: Tarikh: 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.

3 UNIVERSITI TEKNIKAL MALAYSIA MELAKA Karung Berkunci 1200, Ayer Keroh, Melaka Tel: , Faks : fkp@kutkm.edu.my FAKULTI KEJURUTERAAN PEMBUATAN Rujukan Kami (Our Ref) : 20 Mei 2008 Rujukan Tuan (Your Ref): Pustakawan Perpustakawan Universiti Teknikal Malaysia Melaka UTeM, 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 SHAABAN Pensyarah, Fakulti Kejuruteraan Pembuatan (Penyelia Bersama) No telefon: azizahs@utem.edu.my

4 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 Hassan Date : ii

5 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

6 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 C of temperature and followed by crushing process. First sample is sintered at C and second sample sintered at C. 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 C. 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 Fe 2 O 3. 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

7 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 C dan seterusnya dengan proses penggempuran. Sampel pertama disinter pada C dan sampel kedua disinter pada suhu C. 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 C. 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

8 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

9 TABLE OF CONTENT DECLARATION APPROVAL ABSTRACT ABSTRAK ACKNOWLEDGEMENT TABLE OF CONTENTS LIST OF FIGURES LIST OF TABLES LIST OF ABBREVIATIONS, SYMBOLS, SPECIALIZED NOMENCLATURES ii iii iv v vi vii xi xv xvi CHAPTER 1 CHAPTER 2 INTRODUCTION 1.1 Background of the project Problem Statement Objectives Introduction on Magnetic material Ceramic material Ceramic magnet Properties of magnetic material Application of magnetic material 6 LITERATURE REVIEW 2.1 Type of magnetism Diamagnetism Paramagnetism Antiferromagnetism Ferrimagnetism Ferromagnetism Type of ferrites Hard ferrite Soft ferrite Other type of magnetic materials Starting material for strontium ferrite Strontium carbonate 15 vii

10 2.3.2 Iron oxide Ethanol Nickel Previous research on strontium ferrite Process parameter selection for strontium 17 ferrite sintered magnets using Taguchi L9 orthogonal design Barium and Strontium ferrite perpendicular thin film media with a sendust soft magnetic underlayer Fine powders of SrFe12O19 with SrTiO3 additive prepared via a quasi-dry combustion synthesis route Microstructure of pre-sintered permanent magnetic strontium ferrite powder CHAPTER 3 METHODOLOGY 3.1 Powder processing Milling and mixing Calcinations Crushing Sieving Mixing Compact Sintering Sample Characterization Sample preparation for microstructure 28 evaluation Microstructure evaluation Optical microscope Scanning Electron Machine 32 (SEM) Phase analysis Density measurement 35 viii

11 CHAPTER 4 RESULT AND DISCUSION 4.1 Observation on powder As-received material Iron Oxide Strontium carbonate Milled powder Calcined powder Composition Study on Strontium Ferrite Sintered Strontium Ferrite Final Specimens Optical Observation SEM observation Strontium ferrite sinter at 1250 o C Strontium ferrite sinter at 1270 o C Strontium ferrite + 1% Nickel 49 sintered at 1270 o C Strontium ferrite + 2% Nickel sintered at 1270 o C EDX microstructure Strontium ferrite sinter at 1270 o C Strontium ferrite + 1% Nickel 52 sintered at 1270 o C Strontium ferrite + 2% Nickel sintered at 1270 o C Phase analysis Physical properties Mass and Volume measurement Density measurement Defect on sample CHAPTER 5 CONCLUSION AND RECOMMENDATION 60 REFERENCES 62 APPENDIX A 65 APPENDIX B 67 APPENDIX C 69 APPENDIX D 71 APPENDIX E 71 ix

12 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

13 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

14 at.1250 o C 5 0 C/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 o C Figure 4.8 Figure shows SEM image for Strontium ferrite 47 sintered at 1250 o C with different magnification (a) 800x (b) 1500x (c) 5000x. Figure 4.9 Figure shows SEM image for Strontium ferrite 48 sintered at 1270 o C with different magnification; (a) 1500x ( b) 2500x (c) 5000x. Figure 4.10 Figure shows SEM image for Strontium ferrite % Nickel sintered at 1270 o C with different magnification; (a)1500x (b) 2500x (c) 5000x. Figure 4.11 Figure shows SEM image for Strontium ferrite % Nickel sintered at 1270 o C with different magnification; (a)1500x (b) 2500x (c) 5000x. Figure 4.12 EDX result for Strontium ferrite sinter at 1270 o C 51 xiii

15 Figure 4.13 EDX result of Strontium ferrite + 1% Nickel 52 sintered at 1270 o C Figure 4.14 EDX result of Strontium ferrite + 2% Nickel 53 sintered at 1270 o C Figure (a) SEM Backscattered image of strontium ferrite 54 sintered at 1270 without nickel with 2500 x magnification. Figure (b) SEM Backscattered image of strontium ferrite % Nickel sintered at 1270 o C with 2500 x magnification Figure (c) SEM Backscattered image of strontium ferrite % Nickel sintered at 1270 o C with 2500 x magnification. Figure 4.16(a) Specimen after sinter at 1250 o C 58 Figure 4.16(b) Strontium ferrite sinter at 1270 o C 58 Figure 4.16(c) Strontium ferrite + 1% Nickel sinter at 1270 o C 58 Figure 4.16(d) Strontium ferrite + 2% Nickel sinter at 1270 o C 58 xiv

16 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

17 LIST OF ABBREVIATIONS, SYMBOLS, NOMENCLATURES SEM - Scanning Electron Machine EDX - Energy Dispersive X-ray Analysis XRD - X-ray diffraction xvi

18 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

19 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 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

$fracture before any plastic deformation takes place, which results in poor toughness in these materials.$ These combine to give catastrophic failures, as opposed to the normally much more gentle failure modes of metals. These materials do show plastic deformation.

These combine to give catastrophic failures, as opposed to the normally much more gentle failure modes of metals. These materials do show plastic deformation.

20 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 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.

21 Figure 1.1(c): Ceramic Rings Sources: 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 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

22 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 Maximum Intrinsic Normal Residual Coercive Energy Coercive Maximum Curie Magnetic Density Induction Force Product Force Operating Temp. Materials Br Hc BH (max) Hc Temp. lbs/in g/cm MGO Gauss Oersteds Iersteds F C F C Ceramic * Ceramic * Ceramic * Sources: 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

23 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

24 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 Examples Ferromagnetic 107 to 102 Ni, Fe, Co, NiFe, NdFeB Ferrimagnetic 107 to 101 Fe 3 O 4 Ferrite, garnets Antiferromagnetic small MnO, NiO, FeCO3 Paramagnet 10-3 to 10-6 Al, Cr, Mn, Pt, Ta, Ti, W Diamagnetic 10-6 to Ag, Au, C, H, Cu, Si, Zn Sources from Parker(1989) 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 it 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) Paramagnetism 7

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