<4D6963726F736F667420576F7264202D20DDC7D6E120E6C7DFD1E320E6D5C7C8D1EDE439392D313037> Physical and Morphological Properties of Hard- Soft Ferrite Functionally Graded Materials Fadhi Chyad* Akram Jabur** Sabreen Abed*** *, **,***Department of Materials Engineering/University of Technology/ Iraq *Email: fchyad_2009@yahoo.de **Email: akram.jabut@gmail.com ***Email:sabreenali217@gmail.com (Received 20 December 2016; accepted 31 October 2017) https://doi.org/10.22153/kej.2018.10.007 Abstract Functionally graded materials (FGMs), with ceramic –ceramic constituents are fabricated using powder technology techniques. In this work three different sets of FGMs samples were designed in to 3 layers, 5 layers and 7 layers. The ceramic constituents were represented by hard ferrite (Barium ferrite) and soft ferrite (lithium ferrite). All samples sintered at constant temperature at 1100oC for 2 hrs. and characterized by FESEM. Some physical properties were measured for fabricated FGMs include apparent density, bulk density, porosity, shrinkage and hardness. The results indicated that the density increase with the increase the number of layer. Lateral shrinkage is one of the important parameter for estimating the quality of component gradation in an FGM structure. The Vickers hardness show higher value at FGM7, Finally the FESEM images showed a gradation in microstructure within the system from plate- like structure for the hard ferrite to spherical structure for the soft ferrite. Keywords: Functionally graded materials; physical properties of FGM; ceramic; hard ferrite; soft ferrite. 1. Introduction In the previous couple of years, the usage of ceramic materials has amazingly expanded in various applications in view of the particular properties of these materials in examination with metals and polymers. The gainful qualities of ceramic materials are hardness, inflexibility, grating durability and low thickness. Ceramics are a sort of materials by and large characterized as "inorganic, nonmetallic solids". They have the colossal degree of motivation behind every single known material. The most recent decades have seen the advancement of the tremendous capability of practical earthenware production in light of interesting dielectric, ferroelectric, piezoelectric, pyro-electric, ferromagnetic, magneto-resistive, ionical, electronical, superconducting, electro- optical, and gas-detecting properties. Similar logical extensions additionally have occurred in auxiliary ceramic. Thermal, chemical, and mechanical steadiness of numerous oxide and nonoxide mixes have put the reason for improved handling, which prompted an upgraded level of microstructure outline and flaw control. This has progressively directed in at no other time seen improvements in mechanical conduct and in the precision of the properties of parts and devices [1]. Ferrites are categorized mainly into three sets with various crystal types. They are spinel, Garnets and Magneto-plumbite. Spinel ferrites have a cubic structure with general equation MO Fe2O3, where M is a divalent metal particle, similar to Mn, Ni, Fe, Co, Mg, and so forth. Garnets have a complex cubic structure having a general equation M3Fe5O12. The third sort, magneto-plumbite, has a hexagonal structure with general recipe MO. Fe12O18. The most critical in the arrangement of magneto plumbite is barium ferrite BaO Fe12O18, which is a hard ferrite [2]. The quick advancement of new Al-Khwarizmi Engineering Journal Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, March, (2018) P.P. 99-107 Fadhi Chyad Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 99- 107 (2018) 100 high innovation requests an ever increasing number of new materials with various uncommon attributes or capacities. Under some serious boundaries, for example, super high temperature, conventional materials may not serve. Another material idea, practically evaluated materials (FGMs), has been proposed to meet the prerequisite which typically incorporate diverse material constituents, for example, ceramic and metal. FGMs have received significant attention in many engineering applications since they were first outlined in 1980s. They are composite materials, microscopically inhomogeneous, in which the mechanical properties change smoothly and continuously from one surface to the other. Compared with classical laminated composite materials, FGMs supply outstanding thermo-mechanical performances under given loading conditions. FGMs can be utilized to enhance creep behavior, fracture toughness of machine tools, wear resistance, oxidation resistance of high temperature aerospace and automotive components and so on .[3] (Jaworska, et.al.2006) Studied functionally graded cermets. Materials were acquired using free sintering at vacuum and the high temperature-high weight sintering system. Practically evaluated cermets have greater amount of hard stage in the surface layer and lower cooperation of this stage in the body outline. FGMs were set up by the layers pressing operation and the diffusive statement operation. Material with 55 wt.% of TiC and 45 wt.% of (Ni,Mo) was incorporated. The stage's structure of this material was analyzed. (Shabana,et.al.2006) Modeling the development of stress because of differential shrinkage in powder- processed functionally graded metal–ceramic composites during pressureless sintering. This model can be used to decide helpful shrinkage rates and slope structures for a given segment geometry that will restrict the part from breaking amid pressureless sintering by adjusting the advancement of quality, which should be a power law capacity of the porosity, with the improvement of stress. To estimate this model, the powder blend is evaluated as a three-stage material including voids, metal particles, and artistic particles. A micromechanical thermal elastic– viscoplastic constitutive model is then proposed to show the thermomechanical conduct of the composite microstructure. (Shahrjerdi,et.al.2011), demonstrated the functionally graded metal-ceramic composite synthisized through weight less sintering. The unadulterated metallic and ceramic parts are Titanium (Ti) and Hydroxyapatite (HA), which were situated at the finishes of a round and hollow example. FG tests are set up with blending extents of 100:0, 75:25, 50:50, 25:75, 0:100. The barrel shaped specimens had a thickness of 6 mm in size and 20 mm span. Tests are manufactured by utilizing carbon cylindrical die. The ideal thermal load mapping is picked up tentatively. The properties of all FGM items are portrayed by shrinkage, optical magnifying instrument, filtering electron magnifying instrument (SEM), vitality dispersive spectrometry (EDX) and hardness test. (Mahamood,et.al.2012), Proposed an overview of synthesizing method , field of application, some new research studies the need to concentrate more research attempt on improving the most promising FGM synthesizing method (solid free form SFF). Improving the performance of SFF processes and extensive studies on material characterization on components produced will go a long way in lower the manufacturing cost of FGM and increase productivity in this respect. (Mustapha, et.al.2013), suggested an extensive review on the various synthesizing methods of FGMs composed by metallic and ceramic phases. Synthesizing methods in this field of work have comprising many concepts from various background of gradation methods and consolidation or sintering methods (Yu, et.al.2013) Suggested micromechanics display represents multi-stage heterogeneity and discretionary number of layers. The impact of geometries and unmistakable flexible material properties of every constituent and voids on the viable versatile properties of FGM is examined. Numerical cases of different practically reviewed materials are introduced. The predicted elastic properties resulted from the present model work in well with experimental results from the literature. (Fadhil, et.al.2017) Studied dielectric and magnetic properties of nanoferrite functionally graded materials with ceramic –ceramic constituents are fabricated using powder technology techniques. In this work three different sets of FGMs sample were designed in to 3 layers, 5 layers and 7 layers. The ceramic constituents were represented by hard ferrite (Barium ferrite) and soft ferrite (lithium ferrite). All samples sintered at constant temperature at 1100oC for 2 hr. The magnetic properties showed an increase in coercive force (Hc) with increased number of layers. The dielectric properties measured at room temperature with constant frequency 1 MHZ. The results showed the dielectric constant increase with the increase the number of layers from (1.39×10-2) to (2.83×10-2). According to the above literature reviewing, it's clear that the fabrication of hard ferrite\lithium ferrite functionally graded materials is a very new Fadhi Chyad Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 99- 107 (2018) 101 area for investigation that based on using graded ceramic materials. The aim of this work is Fabrication a functionally graded materials (FGMs) from hard ferrite and soft ferrite materials in three different set of multiples layers and then studying the physical and morphological properties of the system. 2. Experimental Procedure 2.1. Starting Materials Nano barium ferrite ( BaFe12O19) , Nano lithium ferrite (LiFe5O8). 2.2. Preparation of Hard/ Soft Functionally Graded Material The start material used to fabricate FGM sample were Nano barium ferrite and Nano lithium ferrite, are weighted in the proportions as shown in Table (1). The formation of a discrete layered graded structure at first requires mixing of the base materials to appropriate composite powder composition. The FGM structure consists of the two base materials on either end of the specimen, with the desired compositional gradient layered between the two as shown in Fig. (1). The FGM system are composed of (3, 5, and 7) layers with thickness (4.5, 8, and 12) mm, respectively. The weight of FGM layer will measured by sensitive balance , the constituents powder were arranged according to the volume fraction of layer starting from lithium ferrite to barium ferrite as mentioned in table (1), After that compacting practice were done under 20000 Mpa load pressure. Each sample was subjected to sintering under temperature of 1100oC for 2 hr. The sintering heating cycle including a slow heating rate with 5 °C∕ min, (see Fig. 2). All sintering practices were carried out by using electric furnace. Fig. 1. Sketch represents FGM system with 3 lay Table1, FGM profil Fig. 2. Single heating cycle of the applied sintering process. 3. Results and Discussion 3.1 Physical Properties 3.1.1 Density and Porosity The (bulk and apparent) density for FGM sample are shown in Fig. (3). Porosity for FGM system was also shown in Fig. (4). the variation of density between the different FGM sample with (3, 5, 7) layer which shown slightly an increase of density with the increase the number of layer; the reason behind such improvement is related to high densification, high homogeneity and good blending between the layer of FGMs [7]. The 3 layer 5 layer 7 layer Weight of LIM(g) Weight of BaM(g) Total thickness 100% LiM 100% LiM 100% LiM 0.4 0 4mm 80% LiM +20%BaM 0.32 0.08 75% LiM+25% BaM 0.3 0.1 65%LiM+35%BaM 0.26 0.14 7mm 50%LiM+50 %BaM 50%LiM+50%BaM 50%LiM+50%BaM 0.2 0.2 35%LiM+65%BaM 0.14 0.26 11mm 25%LiM+75%BaM 25%LiM+75%BaM 0.1 0.3 100% BaM 100% BaM 100% BaM 0 0.4 Fadhi Chyad Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 99- 107 (2018) 102 results of density of prepared FGM sample accompanied by almost slightly increase of porosity at constant sintering temperature. Fig. 3. Density results of FGM samples of (3, 5, 7) layers. Fig. 4. Porosity results of FGM samples of (3, 5, 7) layers. 3.1.2. Lateral Shrinkage Lateral shrinkage is one of the important parameter for estimating the quality of component gradation in a FGM structure. Figure (5) illustrates the effect of change of the percentages among the layers versus the number of layers of the sample sintered at 1100oC for 2 hours. Shrinkage showed an increase in FGM7 as compared with FGM3 and FGM5. The linear shrinkage obtained was an appropriate indicator of the functionality of the design. Fig. 5. Lateral Shrinkage of FGM samples of (3, 5, 7) layers. 3.1.3. Micro Hardness Test Microhardness test was carried out to study the gradient of the mechanical property along the FGMs thickness. In spite of the fact that the phenomenon of hardness is in general is purely a surface property, which represents its resistance to indentation, but in numerous cases the value of surface hardness may be safely used to indication of the state of compactness and integrity of the bulk. The Vickers micro hardness value of FGM sample (3, 5, and 7) layers after sintering practices is presented in Figs. (6), (7) and (8) respectively. It is clear that as the Barium ferrite percentage increased; the hardness is increased. (FGM 3) seems to give graded hardness properties. Also it can be noted that the (FGM 7) layer 7 (100% BaM) and layer 1 (100% LiM) has the higher value of Vickers hardness as compared with (FGM3) and (FGM5) due to increment of density and compacting load. Fig. 6. Vickers hardness values for FGM 3. Fadhi Chyad Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 99- 107 (2018) 103 Fig. 7. Vickers hardness values for FGM 5. Fig. 8. Vickers hardness values for FGM 7 3.2. FE-Scanning Electron Microscopy (FESEM) Analysis Field emission Scanning electron microscope (FESEM) is used to visualize the microstructure of functionally graded materials by scanning with high energy electron beams. Fig. (9) Shows the microstructure of the fabricated LiM\BaM FGMs. It has three layers: the 1st layer (pure BaM) plate like structure with the average size (150-350)nm plus few spherical structure of size (150-200)nm, the 2nd layer mixed both plate of size lightly larger (250- 400nm)average and spherical of size (400nm) while the 3rd layer (pure LiM) is spherical structure of 500 nm average size , respectively. Fig. (10) Shows the microstructure of the fabricated LiM\BaM FGMs. It has five layers: the 1st layer (pure BaM) plate like structur with the average size (150-300) nm, 25LiM&75BaM, 50LiM&50BaM, 75LiM&25BaM (mixed both plate and spherical structure) with the average size (300,700,350) nm, respectively. The 5th layer (pure LiM) spherical less porous dense structure with average size (400-1500) nm, respectively. Fig. (11) Shows the microstructure of the fabricated LiM\BaM FGMs. It has seven layers: the 1st layer (pure BaM) plate like structure with average size (250-350)nm,35 LiM&65BaM plate like thickness range (350-400)nm,50LiM &50BaM plate more thick (400)nm, 65LiM &35 BaM plate less thick (250)nm, 75LiM & 25 BaM nm spherical (250-1000)nm more dense less porous, 80 LiM &20 BaM spherical (350-1000)nm, the 7th layer (pure LiM) spherical structure (more growth, spherical large, less porous), respectively. From the SEM images of 3rd layer FGM3 Fig.(8c), 5th layer of FGM5 Fig.(9e) and 7th layer of FGM 7 Fig.(10g) it can be seen the grain patterns exhibited totally spherical- like structure , a clear crystalline structure was also observed. Also it can be seen a large growth in size at the 3rd , 5th and 7th layer because of the remaining of one phase and disappearances of the other which use to be suppress the growth at the other layer. In contrast, as shown in SEM images of 1st layer FGM3 Fig. (8a), 1st layer of FGM5 Fig.(9a)and 1st layer of FGM7 Fig.(10a) the grain morphology appear totally plate -like shape which is clearly indicated the formation of barium ferrite. Barium hexaferrite nanoparticles with plate-like morphology is the best for the electromagnetic wave absorption application [9]. Also for the composite layer SEM images show the grain microstructure as a combination of spherical and plate like structure which is an evidence for the gradation in FGMs samples and resulting in properties variation. Fadhi Chyad Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 99- 107 (2018) 104 (a) (b) (c) Fig. 9. FE-SEM of FGMs sample with 3 layers: a) first layer, b) second layer and c) third layer. (a) (b) (c) (d) (e ) Fig. 10. FE-SEM of FGMs sample with 5 layers: a) first layer, b) second layer, c) third layer, d) fourth layer and e) fifth layer. Fadhi Chyad Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 99- 107 (2018) 105 (a) (b) (c) (d) ( e) (f) (g) Fig. 11. FE-SEM of FGMs sample with 7 layers: a) first layer, b) second layer, c) third layer, d) fourth layer and e) fifth layer, f) sixth layer and g) seventh layer. 4. Conclusions Functionally graded BaM/LiM specimens have been fabricated at three different set of layer (3, 5 and 7) by powder metallurgy. Characterization of fabricated FGMs was carried out by FESEM which revealed gradation in microstructure from plate- like structure (hard ferrite) to spherical structure (soft ferrite). The result of density indicate the high homogeneity and good blending between the layers of FGM led to increasing of density. The Vickers hardness showed higher value at FGM7 layer 7. 5. References [1] Feng Shi, "Ceramic Materials - Progress in Modern Ceramics", In Tech, pp.65-82, 2012. [2] Sindhu S.," Preparation and Characterization of Spinel Ferrite- Their Incorporation in Rubber Fadhi Chyad Al-Khwarizmi Engineering Journal, Vol. 14, No. 1, P.P. 99- 107 (2018) 106 Matrix and Evaluation of Properties", Department of Physics Cochin University of Science and Technology Cochin, India, PhD Thesis, 2001. [3] M. Tahani , M.A. Torabizadeh and A. Fereidoon,"Nonlinear Analysis of Functionally Graded Materials" ,JAMME, Vol. 18 , pp.315- 318 ,2006. [4] L. Jaworska , M. Rozmus , B. Królicka , A. Twardowska ," Functionally Graded Cermets", Journal of Achievements in Materials and Manufacturing Engineering, Vol.17,pp.73-76, 2006. [5] Rasheedat M. Mahamood, Esther T. Akinlabi Member, IAENG, Mukul Shukla and Sisa Pityana," Functionally Graded Material: An Overview", Proceedings of the World Congress on Engineering, Vol. III, 2012. [6] Jaesang Yu, Cheol-Min Yan and Yong Chae Jung," Micromechanics Modeling of Functionally Graded Materials Containing Multiple Heterogeneities" ,Composite Research, Vol.26, pp.392-397, 2013. [7] Mahmoud Samir EL-Wazery and Ahmed Reffat EI-Desouky," Fabrication and Characteristics of 8YSZ/Ni Functionally Graded Materials by Applying Spark Plasma Sintering Procedure", Int. J. Appl. Sci. Eng., Vol. 12, pp.313-321, 2014 [8] F. Attiay, A. Raheem, S. Ali," Studying Dielectric and Magnetic Properties of Nano Ferrite Functionally Graded Materials" Energy Procida, accepted paper, 2017. [9] Tatyana Koutzarova , Svetoslav Kolev, Kornely Grigorov , Chavdar Ghelev, Andrzej Zaleski , Robert E. Vandenberghe , Marcel Ausloos , Catherine Henrist , h, Rudi Cloots , and Ivan Nedkov," Structural and Magnetic Properties of Nanosized Barium Hexaferrite Powders Obtained by Microemulsion Technique", Trans Tech Publications, Switzerland, Vol.159, pp.57-62, 2010. )2018( 99- 107 ، صفحة1د، العد14دجلة الخوارزمي الهندسية المجلم صابرين عبد 107 ناعم المتدرجة وظيفيا -لمواد الفرايت صلب ةوالمورفولوجي ةالخصائص الفيزيائي *** عبد صابرين **أكرم جبر *فاضل جياد قسم هندسة المواد/ الجامعة التكنولوجية*،**،*** fchyad_2009@yahoo.de:البريد االلكتروني* akram.jabut@gmail.com **البريد االلكتروني: sabreenali217@gmail.comالبريد االلكتروني: *** الخالصة من عينات المواد ةنماذج مختلف ةفي هذا العمل تصنيع ثالثوتم سيراميك بأستخدام تقنية تكنلوجيا المساحيق. -المواد المتدرجة وظيفيا بمكونات سيراميك يثيوم) . فرايت الل) والفرايت الناعم (طبقات. المكونات السيراميكية متمثلة بالفرايت الصلب ( فرايت الباريوم ٧طبقات و ٥طبقات , ٣المتدرجة وظيفيا الى الماسح االلكتروني. لقد تم قياس بعض الخصائص ساعتين وتم تشخيصها بتقنية درجة سيليزيه لمدة١١٠٠جميع العينات تم تلبيدها بدرجة حراره ثابته عند زداد بأزدياد . أوضحت النتائج ان الكثافة تةتتضمن الكثافه الظاهرية, المضخمه,المساميه,االنكماش والصالد ةلعينات المواد المتدرجة وظيفيا المصنع ةالفيزيائي المواد داخل تركيب المواد المتدرجة وظيفيا. أوضحت صالدة فيكرز اعلى القيم عند يم حدوث تدرج بومن اهم العوامل لتق دد الطبقات. االنكماش الخطي يعدع من شكل صفائحي في الفرايت الصلب الى شكل كروي في الفرايت ةداخل المنظوم امجهري اوأخيرا أظهرت صور الماسح االلكتروني تدرج , FGM7عينة الناعم.