Synthesis and Sintering

Synthesis, sintering and electrical properties of Li1+x GaxZr2-x(PO4)3 solid electrolytes for Li-ion batteries

Zahra Khakpor — 2025-03-30

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Investigating the effect of different binders on Alumina-spinel castable refractory

Sahar Sajjadi Milani — 2025-03-29

Al2O3-spinel castable refractory has many advantages, such as high refractoriness, high resistance to chemical attack, and high mechanical strength, so Al₂O₃-spinel castable refractory is widely used in the steel ladle linings below the slag line. In this study, the effect of different binders on Alumina-spinel castable refractory was investigated. Three different sol systems, including alumina, spinel, and silica sol, were separately used as a bonding agent in alumina-spinel-based ultra-low cement castable refractory. The phase composition, microstructure, and mechanical properties of castable refractories, such as bulk density, apparent porosity, and cold compressive strength have been evaluated. In the end, the properties of the castables with sol-gel bonding were compared with those with hydraulic bonding (calcium aluminate cement). It was observed that the castables containing silica sol resulted in higher cold compressive strength (2103 kg/cm²) and higher bulk density due to the absence of low melting or eutectic phases and formation of the mullite phase.

The effects of calcination atmosphere and Fe3+ content on NiFexAl2-xO4 nano pigments synthesized via a polyacrylamide gel method

Rayehe Tavakolipour — 2025-03-28

In this research, NiFe_xAl_2-xO₄pigments (x=0, 0.3, 0.7, and 1.5) were synthesized using a polyacrylamide gel method and the effects of calcination atmosphere and the dopant amount on the formed phases and optical properties were investigated. The physical, optical, and microstructural properties of the obtained pigments were clarified using the XRD, UV-Vis spectroscopy, and FESEM techniques. The phase analysis showed that the nickel carbide was formed in the reducing atmosphere instead of the spinel phase. So, the rest of the samples were prepared in an oxidizing atmosphere. The obtained pigments had a spherical morphology and a narrow particle size distribution due to the growth inhibitor role of the polyacrylamide network. The iron ions entered both tetrahedral and octahedral sites of the nickel aluminate structure, acted as the main chromophore, and turned the color from cyan to brown. Further addition of iron led to the darkening of the brown color.

Characterization of hot-pressed biodegradable zinc-based nanocomposite implant materials reinforced with 10 wt% Mg, WE43, and AZ91

Onur Fevzi Kevenlik — 2025-03-09

Compared to permanent orthopedic implants for load-bearing applications, biodegradable implants provide the advantage of eliminating the necessity for surgical removal after the healing process. Furthermore, magnesium alloy powder reinforced zinc matrix implant materials have been produced to enhance the mechanical properties, biocompatibility, and a proper degradation rate with the growth rate of new bones. This study aims to fabricate Zn-10 wt% Mg, Zn-10 wt% WE43, and Zn-10 wt% AZ91, and alloys along with pure Zn sample for control purpose, using the powder metallurgy production method. In this context, hot pressing was applied to samples at 200°C and 300°C temperatures, under a constant pressure of 400 MPa in order to optimize the fabrication parameters. Scanning Electron Microscope (SEM), Energy Dispersive Spectrometry (EDS), Vickers macro- and micro-hardness test (HV), and X-Ray Diffraction Spectroscopy (XRD) analyses were performed to investigate the influence of press temperatures on the microstructure, elemental components, and mechanical properties of the fabricated samples. The microstructures of the zinc matrix nanocomposite samples reinforced with magnesium alloys predominantly consist of MgZn₂, Mg₂Zn₁₁, and MgO phases dispersed within the refined zinc matrix. The obtained results clearly indicate that ZnMg alloy nanocomposites hold significant potential as biodegradable orthopedic implant materials, however, it is possible to further improve the properties of the material by optimizing the production parameters.

Keywords: Zn-Mg alloy, Powder metallurgy, Biodegradability, Mechanical properties.