Development of Fe-5Al-1C Alloys for Grinding Ball

Our object of research is to combine the properties of Mn and the advantages of Fe-Al-C to improve the performance of grinding ball materials. Three Fe-5Al-1C alloys with compositions of 15 wt% Mn (FAM15), 20 wt% Mn (FAM20), and 25 wt% Mn (FAM25) were investigated. Argon gas was used to assist the removal of dissolved oxygen and to control the formation of metal oxides during Fe-Al-Mn-C (FAMC) fabrication. Microstructure analysis was conducted using scanning electron microscopy, and the Vickers microhardness tester was used to evaluate hardness. To guarantee the Fe-5Al-1C-Mn alloy phase, X-ray diffraction (XRD) test was performed. The EDS test was carried out to show the composition at different points and to observe the presence of several phases in the FAMC alloy system. A pin-on-disc method was employed for a dry sliding wear test, and corrosion testing was performed using the three-electrode cell polarization method. With the addition of Mn, the Vickers hardness of the FAMC alloy raised from 194.4 VHN at 15 wt% to 265 VHN at 25 wt%. The tensile strength and fracture elongation values were 424.69 MPa, 27.16 % EI; 434.72 MPa, 33.6 % EI; and 485.71 MPa, 38.48 % EI for FAM15, FAM20, and FAM25, respectively. A crucial factor for increasing the performance of grinding ball is the wear mechanism. The wear rate results for FAM25 show a decline of more than 57 % compared to FAM15 due to an increase in the hard intermetallic area. The addition of Mn elements increased the corrosion resistance of the FAMC alloys; the lowest corrosion rate occurred at 25 wt% Mn content at up to 0.036 mm/yr. According to the experimental results, the FAM25 alloys have the highest mechanical and corrosion resistance of the three types of alloys. The FAMC alloy is a promising candidate for application as a material for grinding balls by optimizing the Mn conten

Design of Solid Oxide Structure on the Composite Cathode for IT-SOFC

Solid oxide structure of the cobalt-free composite has been exploited as a new cathode material for IT-SOFCs. The composite model system was synthesized using the metallic oxide material, which was formed by a solid-state reaction technique. The generation of the Sm0.5Sr0.25Ba0.25FeO3-δ (SSBF) model system was carried out during the sintering process. The weight loss and oxygen content were investigated by thermal gravimetric analysis (TG). Meanwhile, X-ray diffraction characterized the structure of the composite and thermal conductivity tested the conductivity properties. The results showed that the structure of the SSBF composite demonstrated the perovskite single phase leading to the structural design. The decomposition and evaporation of the constituent elements of the composite corresponded to weight losses during the constructing process. The oxygen content of the model system was 2.98 after the calcination process. The electrical conductivity value reached 2 S cm-1 at 400 °C and increases to a maximum of 7.5 S cm-1 at 710 °C. The metallic element played to generating the conductive behavior at the low temperature, while the ionic structure acted as elevated temperature. So, mixed ionic and electric conductors (MIEC) were employed comprehensively for creating the conductive properties. Based on the structure and conductivity results, the SSBF composite has a good chance as an alternative cathode material with a perovskite single phase for future TI-SOFCs application

Development of Cobalt-free Oxide (Sm0.5Sr0.5Fe0.8Cr0.2O3-δ) Cathode for Intermediate-temperature Solid Oxide Fuel Cells (IT-SOFCs)

A cobalt-free perovskite oxide Sm0.5Sr0.5Fe0.8Cr0.2O3-δ (SSFC) has been exploited as a novel cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The cathode model was synthesized with the addition of the chromium element in the B side of the composite metallic oxide system, which was then formed by the solid-state reaction method. The model system was further characterized in detail for getting the properties behavior. The solid-state reaction of the SSFC system was observed through thermal gravimetric analysis. Meanwhile, the structural properties were investigated by x-ray diffraction, and the weight loss was examined by the thermal gravimetric analysis as well. Furthermore, the thermal expansion coefficient was determined by the thermal-mechanical analysis, and the conductivity properties were tested by the thermal conductivity analysis. The result showed that the SSFC cathode demonstrated the crystalline structure based on the design with a perovskite phase. The oxygen content created on the model structure was obtained to be 2.98 after the calcination process. The average thermal expansion coefficient was achieved up to 5.0×10-6 K-1 as the heating given up to 800 °С. Moreover, the conductivity value reached from 2 S∙cm-1 at 400 °С and it increased to be a maximum of 7.5 S∙cm-1 at 700 °С. In addition, the presence of Cr6+ cation valence coordinated with the oxygen anion could lead to generating a large concentration of oxygen vacancies on the cathode surface, facilitating the transport of the O2− anion in the cathode system. Based on these results, the SSFC cathode has good properties as a composite system promising for IT-SOFCs application in the futur

An Analysis of SmBa0.5Sr0.5Co2O5+δ Double Perovskite Oxide for Intermediate–temperature Solid Oxide Fuel Cells

The main obstacle to solid oxide fuel cells (SOFCs) implementation is the high operating temperature in the range of 800–1,000 °C so that it has an impact on high costs. SOFCs work at high temperatures causing rapid breakdown between layers (anode, electrolyte, and cathode) because they have different thermal expansion. The study focused on reducing the operating temperature in the medium temperature range. SmBa0.5Sr0.5Co2O5+δ (SBSC) oxide was studied as a cathode material for IT-SOFCs based on Ce0.8Sm0.2O1.9 (SDC) electrolyte. The SBSC powder was prepared using the solid-state reaction method with repeated ball-milling and calcining. Alumina grinding balls are used because they have a high hardness to crush and smooth the powder of SOFC material. The specimens were then tested as cathode material for SOFC at intermediate temperature (600–800 °C) using X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), electrochemical, and scanning electron microscopy (SEM) tests. The X-ray powder diffraction (XRD) pattern of SBSC powder can be indexed to a tetragonal space group (P4/mmm). The overall change in mass of the SBSC powder is 8 % at a temperature range of 125–800 °C. A sample of SBSC powder showed a high oxygen content (5+δ) that reached 5.92 and 5.41 at temperatures of 200 °C and 800 °C, respectively. High diffusion levels and increased surface activity of oxygen reduction reactions (ORRs) can be affected by high oxygen content (5+δ). The polarization resistance (Rp) of samples sintered at 1000 °C is 4.02 Ωcm2 at 600 °C, 1.04 Ωcm2 at 700 °C, and 0.42 Ωcm2 at 800 °C. The power density of the SBSC cathode is 336.1, 387.3, and 357.4 mW/cm2 at temperatures of 625 °C, 650 °C, and 675 °C, respectively. The SBSC demonstrates as a prospective cathode material for IT-SOF