Papers by Keyword: Solid State

Abstract: Nowadays, the growing demand for sustainable solutions in manufacturing has shifted research attention toward innovative recycling strategies. Among these, the Solid-State Recycling (SSR) technique has emerged as a viable approach to transform metal swarf into new products. Within the SSR family, friction stir extrusion (FSE) has gained particular interest as a promising method for producing wires from metal scraps, but recently, it was also employed for tube manufacturing. In literature, tube production via chip recycling often involves multi-step approaches, first consolidating/homogenizing the recycled chips and then extruding. In other cases, the tubes are manufactured directly from a bulk material, losing the sustainable goal. For this reason, this study aims to propose a single-step process in which aluminium chips are directly turned into a consolidated tube without any intermediate step. In addition, specific attention was given to the study of tool geometry, aiming to investigate the effect of a tapered tool’s shape on the material flow and the overall process performance. Experimental tests were conducted to characterize the microstructure of extruded tubes and to calibrate numerical simulations employed for investigating process dynamics. Results revealed that the reduced contact diameter of the chamfered tool generated lower processing temperatures but higher strain levels, fundamentally shifting the bonding mechanism from thermal assistance to mechanical dominance in oxide film breakage. Microstructural analysis demonstrated that the flat tool, characterized by predominant frictional heating and lower deformation, produced larger grain diameters due to thermally induced coarsening. Conversely, the chamfered tool yielded significantly refined grain structures through severe plastic deformation and dynamic recrystallization under suppressed thermal conditions, indicating superior consolidation quality and enhanced particle bonding.

Abstract: The storage of electrical energy is an important thing today because it is influenced by the increasing human energy needs. Batteries are one of the energy storage that continues to be explored. Sodium-ion batteries are batteries that are planned to replace lithium-ion batteries. The abundance of sodium elements and their more economical price than lithium are the main attractions. The main constituent components of sodium batteries are anodes and cathodes. Both have a significant influence on the performance of sodium batteries. Currently, several cathodes have been developed but have some challenges especially their instability to air exposure. NaNi_0.5Ti_0.5O₂ is a transition metal oxide-based cathode that has been known to have good structural stability. In this study, NaNi_0.5Ti_0.5O₂ has successfully developed using a combination method of co-precipitation and solid-state. The precipitant is oxalic acid, while the chelating agent is ammonia. The obtained oxalate precursor was sintered in the airstream. Characterization of NaNi_0.5Ti_0.5O₂ is carried out. XRD patterns demonstrate a hexagonal-layered material structure. The material was achieved after the sintering process, according to FTIR analysis. XRF analysis confirmed the composition of the final product in the form of Ni 54.7% and Ti 45.26%. The SEM test showed uniform particles with an average size of 3 microns. Small particle size, which allows greater diffusion of Na ions thereby improving electrochemical performance. This structure characterization result shown that the used method has been succeed. The obtained EIS graph is a semi-circle and slope that shows the process of charge transfer of lithium ions on the surface of the material and electrolyte.

Abstract: Bi-Pb-Sr-Ca-Cu-O (BPSCCO) superconductors are recognized as a projectable high-temperature superconductor for high-efficiency electrical applications. The addition of Ti enhances the formation of the Bi-2223 phase from the BPSCCO superconductor. The process of producing BPSCCO superconducting materials with TiO₂ dopants is performed by the solid-state process and the production of wire rolling, consisting of bismuth (III) oxide powder (Bi₂O₃ = 99%), Strontium Carbonate powder (SrCO₃ = 99%), Calcium Carbonate powder (CaCO₃ = 99%), Copper Oxide powder (CuO₂ = 99%), Lead Oxide powder (PbO₂ = 98%) Bi: Pb: Sr: Ca: Cu ratio: 1.6: 0.4:2:2:3 doped by 1 %wt Titanium Oxide powder (TiO₂ = 98.5%). The variables used in this study were the comparison of the sintering method at 860°C for 24 hours and 820 °C calcination for 20 hours, and 850°C sintering for 20 hours. The superconductor characterization was tested through the X-Ray Diffraction (XRD) test, Scanning Electron Microscopy (SEM), and Resistivity test. XRD test results showed the formation of Bi₂Sr₂CuO₆ and Bi₂Sr₅Cu₃O₁₆ phase. SEM results showed an increase in grain size. The resistivity test results showed that all samples formed critical temperatures, 9.6 and 9.5K respectively.

Abstract: Li₄Ti₅O₁₂/Sn was successfully synthesized by a solid-state method using the High Energy Ball Mill Machine as anode for Lithium-Ion batteries. The addition of various (10%, 20%, 30%) Sn-micro particle is aimed to enhance LTO's conductivity and capacity. Characterization of the sample's structure was performed using X-ray diffraction (XRD), which expose the presence of TiO2 rutile and Sn in each sample. The surface area of samples observed using Brunner-Emmet-Teller (BET), which indicates the different surface area of each Sn addition. Scanning electron microscopy (SEM) suggested agglomeration and poor distribution appear in every sample. Cyclic voltammetry (CV) was performed to measure the battery's performance. Two peaks occur as a sign of reversible reaction. The impedance of Li₄Ti₅O₁₂/Sn measured using electrochemical impedance spectroscopy (EIS), the test performed before and after Cyclic voltammetry (CV), each test showed the different result for each sample. Other than EIS and CV, Charge-Discharge (CD) also performed, examinations in different C-rate were performed, and higher Sn concentration leads to lower stability in high C. The result reveals that the addition of 20% Sn optimizes Li₄Ti₅O₁₂ in enhancing capacity and conductivity.

Abstract: An alternative sensor that can be used to monitor Nitrogen Oxide (NOx) levels in the air is an electrochemical sensor type such as Sodium Super Ionic Conductor (NASICON). In this study titanium doping on zirconium was carried out to improve the electrical conductivity of NASICON. This material was synthesized using the solid state method by mixing sodium carbonate, silicon dioxide, zirconium oxide, ammonium dihydrogen phosphate, titanium dioxide and some anhydrous ethanol into the Ballmill for 12 hours, dried at 80 °C for 12 hours then calcined at 1125 °C for 12 hours with heating rate of 2 °C.min^-1. Then the material was pressed at 160 MPa to produce pellets with diameter of 10 mm and the sintering process was carried out at 1175 °C for 12 hours at a speed of 1 °C.min^-1. The doping of Titanium was varied from 0 to 6 mol%. The XRD characterization results indicate that the formed material phase was monoclinic phase and rhombohedral phase. The most optimal electrical conductivity of 5.897x10^-5 S.cm^-1 was obtained by Titanium doping of 6 mol%.

Abstract: Marine structure, coralline materials were converted to calcium phosphate using two different phosphate solutions. The aim was to study the conversion mechanisms under acidic and basic environment at moderate conditions of temperature. Crystal growth and morphology of converted corals were characterized by XRD and SEM respectively. The results suggested that under acidic conditions (H₃PO₄), dissolution and precipitation control and direct the crystal formation and morphology in which transition from plate like to rod like hydroxyapatite structure was favoured. Metastable phase such as monetite formed and transformed to HAp during reaction. During the first hour of the dissolution a monetite and hydroxyapatite mixture precipitates and then the full conversion to hydroxyapatite is observed. On the other hand, under basic conditions (NH₄)₂HPO₄, just diffusional surface conversion of the calcium carbonate structure of coralline materials to hydroxyapatite and a very small amount of tri-calcium phosphate is observed. The mechanism can be classified as the solid-state topotactic ion-exchange reaction mechanism.

Abstract: Currently, many researchers interested studying waste materials to recycle them or reuse them in new products. From the sustainable perspective development, it is necessary to implement new technologies to help reduce waste and thus minimize the environmental problems associated with disposal. In this study, the preparation of SiO₂-Na₂O-CaO-P₂O₅ (SNCP) glass-ceramic is composed of Soda Lime Silicate (SLS), Clam Shell (CS), Na₂CO₃ and P₂O₅ in the ratio of 50: 25: 20: 5 respectively. The waste materials that were used for fabricate glass-ceramic are SLS and CS. All the compounds were mixed to fabricate the SNCP glass-ceramic through solid state reaction. The samples were investigated through X-ray diffraction (XRD), field emission microscope (FESEM) and density measurement. The samples were sintered at temperature 550°C, 650°C, 750°C, 850°C until 950°C. The main phase obtained from XRD analysis is Sodium Calcium Silicate, Na₂CaSiO₄ with cubic crystal system at 550°C. The highest intensity phase of the diffraction peak is (220) and at the angle 33.7°. There was new peak presence at right side of the main phase Na₂CaSiO₄, which belong to Silicon Phosphate, SiP₂O₇ at 650°C and 750°C. When heat treatment increased at 850°C - 950°C, the main phase is Combeite, Na₄Ca₄(Si₆O₁₈) at diffraction peak (220) with rhombohedral crystal system which is assigned to high crystallization temperature (T_c). The density of samples increases at 550°C - 750°C and decreases when heat treatment 850°C - 950°C. Sample density decreases at heat treatment 850°C - 950°C due to increases of sample lattice parameter. FESEM analysis showed that the grain size and porosity increased when the heat treatment increased.

Abstract: Low density HTSC with nominal composition of Bi_1.6Pb_0.4Sr₂Ca₂Cu₃O_y filled with crystalline sucrose has been synthesized and its structucal and superconducting properties have been studied. The transport properties, morphology, density and structural identification were determined by using the standard four point probe, Field Emission Scanning Electron Microscope (FESEM), densitometer and X-ray diffraction (XRD) respectively. The critical current density (J_c) of optimized ratio of crystalline sucrose onto Bi-2223 powder used to produce low density Bi-based superconductor was found to be higher than the bulk polycrystalline sample. T_{C zero} obtained was varied between 93 and 101 K towards the increment ratio of crystalline sucrose with the highest T_{C zero} = 101 K for ratio of 0.050:1.950 and decrease gradually for further addition of cystalline sucrose. The crystallographic structures was found to be remained in tetragonal where a=b≠c. The grains with higher porosity resulting in decreasing of critical current density (J_c) as well as critical temperature (T_{c zero}) due to lack of effective area of current flows.

Abstract: In this paper, coal fly ash was modified by the hydrothermal synthesis method based on sodium hydroxide solution, and then was macerated by ethanol amine. Then we obtained the solid amine adsorbents used to absorb CO₂. The modified fly ash was investigated by scanning electron microscope (SEM) and the specific surface area analyzer (BET) for the microstructure and specific surface area. Then, the solid CO₂ adsorbent was analyzed by fourier transform infrared spectrometer (FT-IR) and thermal analyzer (TGA) in CO₂ atmosphere. Results showed that modified fly ash generated many kinds of zeolite material by the SEM and the BET analysis, greatly increasing the specific surface area, improved the adsorption capacity. FT-IR analysis that the surface of solid amine CO₂ adsorbent with amine groups; TGA analysis that compared with the original fly ash, CO₂ adsorbent by this paper made has the capability of adsorption of CO₂.

Abstract: This paper focused in details about dielectric properties of BT with different stoichiometry. In this research, BT was synthesis by solid state reaction between TiO₂ and BaCO₃ at constant sintering temperature of 1350 °C. Five different ratio of BT was characterized by using SEM, XRD, and IS. There have production of secondary phase when Ba was excessive. Impedance plot shows the relation between dielectric properties and stoichiometry of BT where the highest value of dielectric properties is comes from sample with Ba/Ti ratio equal of 1:1.