The master sintering curve (MSC) theory is one of the widely used theories to predict the densification behaviour of a given powder and green body irrespective of its thermal history. In this paper, MSC was constructed for a high Curie temperature piezoelectric, \mathrm{La_2}\mathrm{Ti_2}\mathrm{O_7} . Powder synthesis was carried out by the solid state reaction method, followed by uniaxial pressing to obtain green compacts. Dilatometric shrinkage study of green compacts was carried out up to 1450°C with heating rates of 5, 10 and 15°C/min. The apparent activation energy of sintering was found to be 1027 kJ/mol. The results of the present study can be used to predict the densification level obtained during pressureless sintering of the \mathrm{La_2}\mathrm{Ti_2}\mathrm{O_7} powders synthesised by the solid-state method.
This study investigates the effect of substituting \mathrm{Al_2}\mathrm{O_3} with \mathrm{B_2}\mathrm{O_3} (0-4mol%) in nepheline-based glasses intended for advanced dental applications. Differential scanning calorimetry, X-ray diffraction, Raman spectroscopy, dilatometry and scanning electron microscopy were used to examine the structural and thermal evolution of the modified compositions. Increasing B2O3 content decreased the glass transition and softening temperatures and suppressed nepheline crystallisation, leading to the enhanced amorphous stability. Raman analysis revealed progressive network depolymerisation due to the conversion of Al-O-Si linkages to BO3 structural units, while dilatometry demonstrated improved thermal expansion compatibility with zirconia and metal substructures. SEM confirmed that higher \mathrm{B_2}\mathrm{O_3} levels reduced crystal formation and yield smooth, homogeneous microstructures ideal for aesthetic dental applications. The results show that \mathrm{B_2}\mathrm{O_3} contents of 2-3mol% provide optimal thermal behaviour, translucency potential and structural uniformity, positioning these compositions as promising candidates for use in dental veneering porcelains, pressable glass-ceramics and CAD/CAM restorative materials.
This study presents a novel and sustainable precipitation method for synthesis of \mathrm{Fe_3}\mathrm{O_4} /ZnO composite powder directly from corrugated galvanised iron (CGI) waste, addressing gaps in waste-derived catalysts for advanced oxidation processes. XRD characterisation revealed that the \mathrm{Fe_3}\mathrm{O_4} /ZnO powder contains the dominant \mathrm{Fe_3}\mathrm{O_4} (magnetite) crystalline phase with minor amount of ZnO phase. FTIR spectroscopy verified Fe-O (571 cm−1) and Zn-O (450-500 cm^{-1} ) bonds, while XPS confirmed coexistence of Fe^{2+} / Fe^{3+} (710/724 eV) and Zn^{2+} (1022/1045 eV) cations essential for redox cycling. The composite powder showed irregular, agglomerated morphology (SEM/TEM, 20-150 nm particles), mesoporosity (BET 22.69 m^ {2} /g, Type IV isotherm) and superparamagnetic properties (Ms ≈ 51 emu/g). Preliminary Fenton-like tests achieved 85.47% methylene blue (MB) degradation in 60min (first-order reaction, k = 0.024 min^{-1} ) via •OH generation, with >93% efficiency over 4 reuse cycles and facile magnetic separation. This reinforces waste valorisation for sustainable wastewater treatment, demonstrating a synergistic effect at the \mathrm{Fe_3}\mathrm{O_4} /ZnO interface for scalable environmental remediation.
Boron carbide ( \mathrm{B_4}C ) ceramics, owing to their ultra-high hardness, low density and excellent neutron absorption capability, have significant potential in applications such as armour, nuclear industry and cutting tools. However, their inherently low fracture toughness at ambient temperature and difficulty in achieving full densification during sintering limit broader utilisation. In this study, TiB2 reinforcement phases were fabricated in situ within \mathrm{B_4}C via high-temperature and high-pressure sintering. The influence of sintering temperature on the phase composition, microstructure and mechanical properties of the \mathrm{B_4}C - \mathrm{TiB_2} composites was systematically investigated to optimise the sintering process and performance. The results indicate that, with increasing sintering temperature, Ti progressively reacts with \mathrm{B_4}C to form \mathrm{TiB_2} , achieving complete Ti consumption at 1300°C. At 1500°C, the composites exhibited optimal performance: relative density of 99.6%TD, Vickers hardness of 35.2GPa, flexural strength of 694.6MPa, and fracture toughness of 8.2MPa•m1/2. Further temperature increase to 1600°C led to abnormal grain coarsening and consequent properties degradation. High-temperature and high-pressure sintering combined with in situ reaction enables the fabrication of highly dense, high-performance \mathrm{B_4}C - \mathrm{TiB_2} composites, with temperature of 1500°C identified as the optimal sintering temperature. This work provides not only a viable pathway for manufacturing, but also a theoretical basis for designing high-performance B4C composites.
The present work developed a methodology for synthesising single-phase nanopowder based on an ordered phase with LaLuO3 perovskite type structure. The LaLu \mathrm{O_3} : Yb^{3+} nanopowder, doped with 2mol% Yb^{3+} , was synthesised by wet-chemical method from precursor nitrate solution and thermal treated to form pure perovskite phase. The synthesised nanopowder was comprehensively studied using IR spectroscopy, X-ray diffraction, scanning electron microscopy and adsorption-structural methods. The results of the X-ray diffraction analysis indicate that the synthesised powder is single-phase, with all the formed diffraction peaks corresponding to the ordered structure of the LaLu \mathrm{O_3} perovskite type. The unit cell parameters of the LaLu \mathrm{O_3} : Yb^{3+} (2mol%) phase are: a = 0.6023 nm, b = 0.8385 nm, c = 0.5822 nm and V = 0.294 nm3 whereas the average crystallite size is 51.2 nm. The nanopowder was consolidated using the spark plasma sintering (SPS) technique at 1380°C and 50MPa with dwell of 15min, resulting in a fully dense ceramic material of 8.16 g/ cm^{3} (i.e. 99.54% theoretical density).
