Papers by Keyword: Solid State Reaction

Abstract: The synthesis of ceramic composites consisting of cerium and titanium-doped zirconium (ZCT) oxide was achieved by the solid-state reaction technique. The ZCT composite ceramic powder undergoes sintering at various temperatures, including room temperature (RT), 1000°C, 1100°C, 1200°C, and 1300°C. Extensive study has been conducted on ceria-based materials in the field of catalysis, owing to their vast array of uses. Nevertheless, there was a limited amount of research conducted on the impact of ceria in the solid-state reaction approach. The current study employed a solid-state reaction method to fabricate ceramic composites comprising ZrO₂, CeO₂, and TiO₂. Various sintering temperatures were employed in the process. This study aimed to evaluate the impact of the sintering effect of ZCT ceramic oxides on several aspects, including crystal structure, surface morphology, optical properties, and electrical properties. The ZCT ceramic oxide underwent sintering at room temperature (RT), 1000°C, and 1100°C, resulting in the formation of a monoclinic crystal structure. However, sintering at 1200°C and 1300°C led to the presence of mixed phases, characterized by both monoclinic and tetragonal crystal structures, as observed through X-ray diffraction (XRD) analysis. When the sintering temperature is increased from 1000 to 1300°C, there is a modest drop in the band gap of a ZCT material from 3.43eV to 3.25eV. frequency(1mHZ-200kHz) dependence of dielectric constant, dielectric loss and ac electrical conductivity of the synthesized composites were carried out. The results indicate that dielectric constant and loss decreases with frequency rises and reaches a constant value at higher frequencies. The electrical conductivity of all ZCT samples exhibits an increase as the frequency is raised, whereas it reaches a minimum at lower frequencies.

Abstract: In this study, an increase in the reflection loss (RL) value for SrFe_(11.9-x)In_0.1Sn_x/2Zn_x/2O₁₉ samples (x = 0; 0.10; 0.35 and 0.50) is reported. The X-ray diffraction (XRD) pattern of all samples confirmed that the SrFe_(11.9-x)In_0.1Sn_x/2Zn_x/2O₁₉ samples (x = 0, 0.10, 0.35, and 0.50) posses polycrystalline with single phase. We have demonstrated that co-substitution of Zn²⁺ and Sn⁴⁺ ions with a fraction of x = 0.10 reduced the coercivity of the pure nano strontium hexaferrite (SHF) from 346.80 kA/m to 50.34 kA/m. The substitution of Fe³⁺ ion by Sn²⁺ and Zn⁴⁺ affect the coercivity decreased significantly. Meanwhile, the saturation magnetization and remanence slightly decreases. Hence, the decreasing of coercivity cause the reflection loss (RL) increase from -16.43 dB to -25.62 dB. We believed the RL value can be increased efficiently by reducing the coercivity of the sample obtained by co-substitution of Zn²⁺ and Sn⁴⁺ ions to Fe³⁺ in the main phase of SrFe_11.9In_0.1O₁₉.

Abstract: La_0.7Ba_0.3Mn_1-xFe_xO₃ (x = 0 and 0.02) were prepared by using solid state synthesis method to investigate the effect of Fe³⁺ substitution at Mn-site on electrical behaviour and structural properties. An analysis of X-ray diffraction, XRD data using refinement method shown both x = 0 and x = 0.02 samples were in single phased and crystallized in rhombohedral structural with Pnma space group. From ρ vs T curves shown resistivity decreased under increased of applied current of 10 mA to 20 mA for both samples in the temperature range of 20 K-300 K. The larger electroresistance, ER effect observed for x = 0.02 in temperature range of 20 K – 180 K compared to x = 0 sample is suggested due to the development of filamentary conduction path under increased of applied current. It is suggested that Fe substitution enhanced magnetic inhomogeneity which contribute to the growth of formation of conductive path under increased of applied current, lead to increase of ER effect. In the temperature range of 180 K – 300 K, the observed decreased in ER for Fe substituted sample (x = 0.02) is suggested due to the increased of scattering effect and reduction of available hopping site in metallic region and insulating region, respectively. Restriction in the movement of charge carrier had weakened the ER effect for Fe substituted sample. The observed ER effect indicates the compound has a potential for application such as for non-volatile memory elements.

Abstract: The objective of this study is to produce b-wollastonite from amorphous SiO₂ obtained from bamboo leaf ash (BLA) and CaO derived from meretix meretix shell (MMS) using solid state reaction. Amorphous SiO₂ utilization in this work obtained by precipitation of BLA and calcined at 700 °C for 3 h, whereas CaO MMS was generated by calcination of MMS at 1000 °C for 5 h. High purity amorphous SiO₂ obtained was 99.325 wt % and CaO purity obtained was 97.531 wt %. Single phase of b-wollastonite found in this study as confirmed by XRD results. The vibrations at 933.42 , 904.49, and 890.99 cm^-1 were caused by the Si-O-Ca bond, which shows the bonding of b-wollastonite obtained from the FTIR. The acicular morphology of b-wollastonite with average grains size of 0.28,0.33 and 0.71 mm was obtained for the samples calcined at 900 , 1000 , and 1100 °C respectively.

Abstract: In this work, comparison of TiO₂ additions on the physical properties of YBa₂Cu₃O_δ superconductor system with nominal starting compositions at x= 0, 1, 2, and 5 wt.% was studied derived via solid state reaction and co-precipitation method. The samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The result from XRD shown that all the samples were polycrystalline for solid state reaction, while single phase appear for co-precipitation methods. The intensity of the peak become higher with increasing amount of TiO₂ addition indicating the presence of increased amount of the unreacted in the samples. The refine lattice parameters indicated that all the samples have an orthorhombic crystal structure without occurrence of orthorhombic-tetragonal phase transformation. Furthermore, from SEM images for solid state reaction and co-precipitation method showed that the grain size of the samples decreased with TiO₂ increased. Small addition of TiO2 derived from co-precipitation method enhanced the YBCO microstructures.

Abstract: The effect of x mole ratio on crystal structure and characteristic of microwave absorption of ZnLa_xFe_(2-x)O₄ system (x = 0.0; 0.01and 0.02) synthesized by solid state reaction method has been studied. The series of ZnLa_xFe_(2-x)O₄ samples were prepared using ZnO (99.99%) and Fe₂O₃ (99.99 %) powders (Merck product), while La₂O₃ (local production) powders in mole ratio. The identification result of the XRD shows that all of samples are single phase in this stage, it has cubic spinel structure with space group F d-3 m. The SEM image of ZnLa_xFe_(2-x)O₄ samples appear that the increase of mole ratio, the particle size of the compound powder rapidly becomes bigger, homogeneous and not uniform powder with spherical in shape and particle size of 200-500 nm. The results of the VNA characterization shows that the increasing of mole ratio (x = 0.0; 0.01 and 0.02) will enhance the ability to absorb microwave from 90.35% upto 97.69%. Thus. the composition of x=0.02 (ZnLa_0.02Fe_1.98O₄) possess to be the best composition for microwave absorbing material.

Abstract: In this paper, BaFe₂O₄ was prepared from BaCO₃ and Fe₂O₃ powders through the solid state reaction method. This method starts by mixing the barium carbonate and iron oxide in order to homogenize the raw materials and takes place in a wet medium. For a better homogenization of BaCO₃ and Fe₂O₃ powders and in order to reduce the monoferrite formation temperature, it was used the mechanical alloying process for 3 and 9 hours in a high energy ball mill. Particle size distributions of the milled powders were analyzed by a BROOKHAVEN 90PLUS device. To understand the phase formation temperature, thermogravimetry analysis was carried out. The phase identification of the calcined powder was carried out by D8 Discover Bruker X-ray diffractometer. The results showed that once with the reduction of powders particle size, in the mechanical alloying process, the temperature of the solid state reaction of barium monoferrite was also reduced.

Abstract: This research is aimed to study the effect of sintering temperature on crystalline structure and surface morphology of NdFeO₃ oxide alloy materials. NdFeO₃ was synthesized by solid state reaction method with mixing of 99.9% Nd₂O₃ and 99.9% Fe₂O₃ as precursors. Three samples with different process were made in this experiment. The 1^st (#1) and 2^nd (#2) samples were sintered for 84 hours at 950°C and 600°C. Calcination procces was carried out at 950°C for 50 hours. The 3^rd (#3) sample was sintered for 84 hours at 600°C without calcination process. The samples were characterized by using SEM (Scanning Electron Microscopy) and XRD (X-Ray Diffraction). Based on the SEM characterization result, it was obtained that the sintering temperature influence on surface morphology of NdFeO₃ grain size. The XRD analyze was obtained FWHM (Full Width at Half Maximum) value of sample #1, #2 and #3 are 0.11°, 0.10°, and 0.31°, respectively. The value of FWHM was associated with the peak at 2Θ of 32.53° for all sample, it is indicated of hkl (121). Further calculation based on crystallography data was carried out by rietveld method with rietica software and the best quality will be applied as a gas sensor materials.

Abstract: Fuel cell is an electrochemical cell which converts chemical energy into electricity via electrochemical reaction of hydrogen and oxygen gases. It is also an alternative energy with environmental friendly. Generally, the fuel cell consists of many parts. Electrolyte is an important part for fuel cell because it has high ion conductivity which leads to increase electrical conductivity of the fuel cell. In case solid oxide fuel cell, barium cerate-based ceramics have been much attention due to their good properties for the fuel cell. In this work, the BaCe_1-xY_xO_3-δ (x = 0.20) ceramic was synthesized by a solid state reaction in order to study their mechanical and electrical properties. The ceramic was sintered at high temperature of 1500°C with various soaking times. The crystalline phase structure was investigated by X-ray diffraction (XRD). The surface morphologies was observed by a scanning electron microscope (SEM). The impedance properties was measured by LCR meter. The obtained results suggestes that the ceramic sinter at 1500°C with 15 h dewell time shows the best properties as compared to other ceramics.

Abstract: We report synthesis of nanosized oxide materials using a novel water assisted solid state reaction (WASSR) method. This novel soft chemical synthesis method is very simple and can synthesize nanoparticle materials just by storing or mixing raw materials added a small amount (typically 10wt%) of water in a reactor at low temperature below 373 K. Combinations of raw materials have a significant influence on the reaction rate.