302 American Academic Scientific Research Journal for Engineering, Technology, and Sciences ISSN (Print) 2313-4410, ISSN (Online) 2313-4402 http://asrjetsjournal.org/ Preparation and Characterization of Barium Titanate Nano Particles Using Solution Combustion Aliaa A. Razzak a* , Mahmood M. Barbooti b , Abeer Abdul Razak Mohammed c a,b Chemistry Division, Applied Science Department, University of Technology, Baghdad, Ira c Collage of Science ,Dpartment of chemistry , Mustansiriryah University a Email:alia.abdulrazzak7@gmail.com or: 100038@uotechnology.edu.iq Abstract Ferroelectric materials are gaining increased importance as a result of their high dielectric constants making them useful for electrical capacitors, high piezoelectric constants to make sensors, actuators, RF Filters, ferroelectric hysteresis suit making non-volatile memories, high pyroelectric properties for infra-red detectors, thermistors, and strong electro-optic effects to be used in optical switches, data storage, etc. Barium titanate undergoes change in shape from perovskite into cubic structure Curie temperature which causes polarization, or spontaneous, polarization. Many techniques were described for the synthesis of Barium titanate including solid- state reaction, sol-gel method, hydrothermal and solution combustion. Solution combustion. The last method offers good control of the properties to meet specific requirements of the products and allows the preparation of nanomaterials to suit energy saving and protection of environment made it attractive for many purposes. In the present work barium titanate is synthesized as submicro to nano sized particles using the solution combustion technique utilizing urea and glycerin as fuel / oxidant mixture. The experimental parameters were varied to suit the optimization of the process. Keywords: solution combustion; nano barium titanate; glycerin urea; annealing; IR spectra; x-ray diffraction. 1. Introduction Ferroelectric materials contain one or more polar axes along which a spontaneous polarization can be developed below the Curie temperature [1]. They offer a wide range of useful physical properties. They are: 1) High dielectric constants making them useful for electrical capacitors, 2) high piezoelectric constants useful in making sensors, actuators, RF Filters, 3) Ferroelectric hysteresis useful to make non-volatile memories, 4) high pyroelectric properties for infra-red detectors, thermistors, 5) strong electro-optic effects used in optical switches, data storage, etc. ------------------------------------------------------------------------ * Corresponding author. http://asrjetsjournal.org/ https://www.sciencedirect.com/topics/physics-and-astronomy/nanomaterial American Academic Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2022) Volume 88, No1, pp 302-311 303 Beyond the curie temperature (130°C) the shape of BaTiO3 changes from perovskite crystal to cubic structure with Ba 2+ ions at the vertices, O 2- ion in the face center position and Ti 4+ ion in a body-centered position. This causes polarization, or spontaneous, polarization as a result of the unit shift of axially elongated Ti 4+ ion crystal and, hence, BaTiO3 shows ferroelectric property [2]. The importance of BT, increased as a ferroelectric material. It is characterized by high dielectric constants, high piezoelectric constants. They are utilized in the manufacture of electrical capacitors, actuators, and radio-frequency, RF, Filters. Optically the material is useful to make infra-red detectors and optical switches [1]. Many techniques were described for the synthesis of BT including solid-state reaction, sol-gel method, hydrothermal and solution combustion. Solid-state reaction involves the milling of BaCO3 or BaO and TiO2 and calcination at high temperature (800 o C to 1300 o C) [3-5]. In sol-gel method a chemical precursor is hydrolyzed to form a sol and then a gel, which on drying (evaporation) and pyrolysis gives an amorphous oxide [6]. Barium acetate, tetrabutyl titanate, isopropyl alcohol and glacial acetic acid were starting reagents. Sol-precipitation process was developed, where no further calcination or annealing of the product is required. The single-crystal BaTiO3 nanoparticles can be directly obtained at the low temperature of 80 o C and a strong alkaline condition rather than amorphous gel that often formed in the standard sol-gel process. From transmission electron microscope, TEM, examination nanoparticles with an average diameter of about 20 nm were detected [7]. Boulos and his colleagues [3] synthesized BaTiO3 powders by the hydrothermal method using two different titanium sources TiCl3 and TiO2. The barium source was BaCl2·2H3O. Synthesis was performed at two temperatures, namely 150 o C and 250 o C. To yield spherical highly crystallized elementary grains with sizes in the nanometer range. Microwave, MW, heating was developed with some advantages over the conventional hydrothermal route like the cost and short time of the process starting with Ba(NO3)2, TiCl4 and KOH [8. 9]. All chemical reactions were conducted in a MW digestion system to give cubic BaTiO3 powders within 15 min compared with 150 min for conventional method (Guo and his colleagues [10]). The material was also prepared in a molten salt at 925 o C. [11]. The BaTiO3 may be doped by solid-state decarbonation at 900 °C and sintering at 1400 °C for 8 hrs restoring the tetragonal crystal phase of BaTiO3 [12]. However, the introduction of Zirconium into the BT structure caused a shift of diffraction pattern to lower angle side. It also affected the structure of perovskite BT [13]. Bachina and his colleagues [14] used various glycine to nitrate mixtures to design a synthesis procedure for nanocrystalline lanthanum ortho ferrite, LaFeO3, with average crystallite size of 18 to 85 nm. The specific surface area of the nano powders based on them ranged from 8 to 33 m 2 /g. The synthesis by solution combustion became a widely accepted method for making a variety of inorganic materials, ceramic and composites[27]. Good control of the properties can be insured to meet specific requirements of the products. The versatility of the method furnished the way to study the optimization of the synthesis conditions. The application of the method towards the preparation of nanomaterials to suit energy saving and protection of environment made it attractive for many purposes. In the present work, BaTiO3 micro to nano size particles are synthesized by solution combustion method. The material will be characterized by advanced chemical and physical techniques. https://www.sciencedirect.com/topics/physics-and-astronomy/ceramics https://www.sciencedirect.com/topics/physics-and-astronomy/nanomaterial American Academic Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2022) Volume 88, No1, pp 302-311 304 2. Materials and Methods 2.1 Materials and Reagents The Ba(NO3)2 and TiO2 used were analytical grade chemicals. Urea was a general purpose material and glycerin was a 98% pure material. Deionized water was used for all the purposes. 2.2 Apparatus The FTIR spectra of the specimens were recorded on a Shimadzu IRAffinity-1S FTIR spectrophotometer where the samples were analyzed as KBr discs. The X-ray diffraction patterns were recorded on a Diffractometer. The TEM images were also measured 2.3 Synthesis Procedures Barium nitrate (26.1337 g, corresponding to 0.1 mole) was dissolved in minimum amount of deionized water and 7.987 g (0.1 mole) of TiO2 were added and mixed thoroughly (Mixture A). Certain amount of urea was dissolved in a minimum amount of water (reagent B). Reagent B was added to mixture A. An aliquot of glycerin was added and water was then added to complete 100 mL. The overall composition of reaction mixtures is indicated in Table 1. The mixture was placed on a hot plate set at the maximum temperature (approximately 180 o C) with continuous stirring for about 30 min. The mixture was removed from the heater surface and ground in a porcelain mortar. The mixture was divided into four portions. One portion was kept for analysis and physical measurements. The second, third and the fourth portions were placed in a Muffle furnace set at 500 o C, 600, and 700 o C, respectively. Heating was continued for about 4 hours and the furnace was allowed to cool overnight. The description of the samples is given in Table 1. The samples were characterized by XRD, TEM and IR spectroscopy. Table 1: Details of barium titanate reaction mixtures and heating conditions* Parameter Run No. 1 2 3 4 5 6 Urea, g 10.0 10.0 10.0 5.0 5.0 5.0 Glycerin, ml 5.0 5.0 5.0 2.5 2.5 2.5 Temperature, o C 500 600 700 500 600 700 Time, hr 4 4 4 4 4 4 * Barium nitrate (26.1337 g) and 7.987 g of TiO2. 3. Results and discussion FT-IR analysis is frequently employed to support the detection of functional groups in organic and inorganic American Academic Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2022) Volume 88, No1, pp 302-311 305 compounds [15]. Thus, it can be used to follow the progress of chemical reactions by detecting the reduction in peak intensity of peaks related to the reactants and the appearance of those of the products [16]. Ianculescu and his colleagues [17] reported that the absorption bands at wave numbers smaller than 800 cm -1 for thin films BT are related to the Ti - O and Ti – O - Ti bands. In the present work FTIR spectra was recorded for all reaction mixtures and their solution combustion and the annealed products at the designed experiments.Typical spectra are displayed in Figures 1 and 2. A peak at 1425± 2 cm -1 characterized all the analyzed samples. A group of peaks appeared at 858 ± 2, 685 ±2, 584 ± 2, 543± 2, and 433± 3 cm -1 were also observed. The peaks of the high temperature annealing were sharper than those recorded for low annealing temperature. This is related to the homogeneity of the compounds and agrees with the report of Brundle and his colleagues [18]. The IR peaks at 485 cm −1 and 732 cm −1 which refers to the O–Ti–O bonding of anatase titanium dioxide morphology (Karakitsou and Verykios) [19] did not show up in all spectra indicating complete reaction. Tetragonal BT appeared dominant phase of the reaction product as the characteristic peak at 584 ± 3 cm -1 [20]. The bands at the range of 570- 400 cm -1 are designated to indicate that cubic and tetragonal BaTiO3 exist in the product according to the temperature, especially 535 (528) and 579 (582) cm -1 may indicate the existence of the tetragonal BaTiO3 [21]. American Academic Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2022) Volume 88, No1, pp 302-311 306 Figure 1: The IR spectrum of the material annealed at 500 Figure 3 and the first three columns of Table 2 reveal the existence of some remaining barium oxide in the product as given by the XRD peaks at 2θ 19.05 (19.65), 25.43 (26.91), 34.04 (33.619), 42.16 (43.0288), 45.21 (44.8540), 56.24 (55.9910), 60.9634, and 68.40 (68.237). The values in parenthesis refer to the barium oxide standard XRD peaks given by Bazeera and Amrina, 2017 [22]. 3.1 X-ray diffraction, XRD, patterns The examination of the specimens by XRD was indicative for the degree of reaction completion as well furnishing information about the structure and the crystalline nature of the products. Table 2 shows the XRD data of the products from reaction heated by a mixture of 5.0 g urea + 2.5 g glycerin. Figure 2: The IR spectrum of the material annealed at 700 o C Figure 3: XRD pattern of the product in the presence of 5.0 g urea and 2.5 g. glycerin heated at 500 o C A large number of peaks showed up referring to the produced BT in addition to some remaining reactants and American Academic Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2022) Volume 88, No1, pp 302-311 307 intermediate products (BaO). The main peaks obtained were 22.48 (22.2), 31.63 (31.5), 38.97 (38.9), 45.24 (45.3), 51.17 (51), 56.23 (56.2), 65.93 (65.8), 70.47 (70.4), 74.95 (74.9) and 79.46 (79.4); the values in parenthesis refer to the BT synthesized by reaction in molten chloride matrix at 925 o C [11]. The Table 2 shows complete disappearance of TiO2 diffraction peaks [23] from the reaction products from all of the studied samples. This is a solid indicator on the activity of the solution combustion to supply the required energy to incorporate TiO2 in the reaction which necessitated heating at temperatures exceeding 900 o C. [24] Figure 4: SEM image of the product in the presence of 5.0 g urea and 2.5 g. glycerin heated at 500 o C Table 2: XRD data of the products from reaction heated by a mixture of 5.0 g urea + 2.5 g glycerin Peak No 500 o C, 600 o C. 700 o C. 2θ D space, Ă I/I1 2θ D space, Ă I/I1 2θ D space, Ă I/I1 1 19.05 4.65343 22 2 22.18 4.00367 19 22.36 3.97271 17 22.44 3.95878 18 3 24.12 3.68744 36 24.18 3.67651 13 24.30 3.65967 14 4 25.43 3.49956 10 5 31.62 2.82692 100 31.72 2.81867 100 31.82 2.8100 100 6 34.04 2.63175 11 7 34.84 2.57318 8 8 36.82 2.43901 27 9 38.84 2.31674 28 39.06 2.30396 31 39.16 2.29840 25 10 42.16 2.14179 11 11 45.21 2.00400 34 45.36 1.99782 38 45.45 1.99377 33 13 46.79 1.93985 8 14 48.97 1.85847 6 15 50.43 1.80821 6 16 50.98 1.78979 11 51.04 1.78796 11 51.17 1.78377 10 17 56.24 1.63424 38 56.32 1.63228 40 56.42 1.62957 38 18 65.93 1.41567 16 65.98 1.41462 22 66.07 1.41290 19 19 68.40 1.37037 10 20 70.50 1.33460 7 70.55 1.33378 6 70.65 1.33211 6 21 74.95 1.26608 12 74.98 1.26558 15 75.06 1.26441 12 22 79.29 1.20728 7 79.38 1.20606 7 23 83.58 1.15585 7 83.67 1.15489 6 American Academic Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2022) Volume 88, No1, pp 302-311 308 Figure 5: SEM image of the product in the presence of 5.0 g urea and 2.5 g. glycerin heated at 700 o C The SEM image (Figure 4) indicated the submicron (517.3 nm) particles partially agglomerated with very few fine particles (56.1 nm). Thus, low fuel / oxidant amount coupled with low annealing temperature (500 o C) allowed only partial disintegration of the particles. By employing higher annealing temperatures, (600 and 700o C), it appeared that the prepared material has fine-grains with a submicron to nanoscale in the range of 65- 310 nm (Figure 5) which is close to those obtained by Khort and Podbolotov [1]. Probably, the main reason for such morphology is that the exothermal reactions during combustion proceed while the components are in a foam like state, which, as mentioned above, originates during boiling of the liquid charge. The aggregation of flaky formations could be explained by a high temperature attained during the synthesis and a high rate of exothermal reactions. The SEM image indicated clear crushing of the particles into almost homogeneous state but with irregular shapes and sharp edges within the submicron range of size. Thus, the increase in annealing temperature (700 o C) caused the disintegration of particles. Figure 6: XRD pattern of the product in the presence of 10.0 g urea and 5.0 g. glycerin heated at 500 o C Table 3 shows the XRD data of the products from reaction heated by a mixture of 10.0 g urea + 5.0 g glycerin. American Academic Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2022) Volume 88, No1, pp 302-311 309 The excess Urea/glycerin content resulted in sort of explosion to yield almost homogeneous mixture of BT particles. The SEM image (Figure 6) indicated the submicron (449.5-877.4 nm) particles partially agglomerate. Thus, the excess fuel / oxidant amount coupled with 600 o C annealing temperature allowed overall crushing of the particles into such low particle sizes and homogeneous. Lee and his colleagues [25] found that the particle size can be easily tuned by adjusting the experimental parameters of the Solvothermal process while retaining the tetragonality. Table 3: XRD data for the products prepared by a mixture of 10.0 g urea + 5.0 g glycerin Peak No 500 o C. 600 o C. 700 o C. 2θ D spac, Ă I/I1 2θ D spac, Ă I/I1 2θ D spac, Ă I/I1 100 22.48 3.95129 18 22.25 3.99217 17 22.53 3.94301 16 2 24.32 3.65676 20 24.08 3.69193 21 24.35 3.65218 22 101 31.85 2.80708 100 31.63 2.82675 100 31.91 2.80228 100 4 34.54 2.59436 8 34.29 2.61260 7 34.24 2.61684 7 111 39.21 2.29593 27 38.97 2.30894 28 39.25 2.29325 30 6 42.30 2.13464 5 42.09 2.14489 7 42.34 2.13299 6 002 45.47 1.99299 30 45.24 2.00284 28 45.51 1.99162 29 8 46.98 1.93249 5 47.07 1.92911 6 210 51.17 1.78370 9 50.99 1.78945 9 51.24 1.78137 11 10 56.46 1.62846 35 56.23 1.63445 39 56.50 1.62729 38 220 66.14 1.41168 16 65.93 1.41558 18 66.17 1.41108 20 13 70.68 1.33164 6 70.47 1.33521 6 70.76 1.33043 6 310 75.15 1.26323 10 74.95 1.26607 10 75.18 1.26267 11 15 79.46 1.20514 5 79.29 1.20731 6 79.45 1.20523 6 16 83.77 1.15370 6 83.57 1.15599 7 83.79 1.15357 7 Figure 7: SEM image of the product in the presence of 10.0 g urea and 5.0 g. glycerin heated at 700 o C American Academic Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS) (2022) Volume 88, No1, pp 302-311 310 Further increase in annealing temperature up to 700 o C resulted in the production of the smallest sizes particle of all specimens. The SEM image (Figure 7) indicated the presence of (58.78 to 293.9 nm) sized particles. Thus, the excess fuel / oxidant amount coupled with 700 o C annealing temperature allowed the crushing of the particles to such low particle sizes. This is in agreement with Maison and his colleagues [26] results using catecholate process. 4. Conclusions Solution combustion can be successfully employed for the preparation of barium titanate utilizing the urea glycerin (fuel/oxidant) system the increase of the use of higher fuel/oxidant content helps in the reduction of annealing temperature. The oxidation process supplies the required heat energy for the reaction and acts to initiate the dissociation of the particle into smaller sized particulate in the submicro to nano scale sizes. Acknowledgement The authors are grateful to Hassan Hadi for his help in carrying out the SEM measurements. References [1]. Khort AA, Podbolotov KB. 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Aliaa A.Razzak, Abdulnasser M.A.,Mohammad J.H.,Preparation of nanocompounds materails by combustion method using urea as fuel, Progress in Industrial Ecology- An International Journal ,2020:14(1):19-29. http://dx.doi.org/10.1080/17458080.2014.980445 https://www.sciencedirect.com/science/article/abs/pii/S0960897418300020#! https://www.sciencedirect.com/science/article/abs/pii/S0960897418300020#! https://www.sciencedirect.com/science/journal/09608974 javascript:void(0) javascript:void(0) http://dx.doi.org/10.1080/17458080.%202014.980445