The Pb4/5Sr1/5 (Z r11/20Ti9/20)O3-Pb(M n1/3Sb2/3)O3-Pb(W1/3Nb2/3)O3 (PSZ T-PM S-PWN) ceramics were prepared via the solid-state reaction method. The effect of sintering temperatures on PSZ T-PM S-PWN phase formation, microstructure and electrical properties were investigated. The X-ray diffraction study confirmed pure perovskite structure formation in the prepared ceramics and the coexistence of rhombohedral and tetragonal phases has been detected in all ceramics at room temperature. Scanning electron micrographs of fractured PSZ T-PM S-PWN ceramics revealed equiaxed grains and the presence of both transgranular and intergranular fracture modes. Optimal electrical properties were obtained at a sintering temperature of 1175oC, characterized by a high dielectric constant (ϵr=12735), a Curie temperature (TC) of 630 K, a dielectric loss (tanδ) of 0.03, a piezoelectric charge constant (d33) of 341 pC/N, an electromechanical coupling factor (KP) of 0.624, and a mechanical quality factor (Qm) of 1260. These properties indicate strong potential for applications in piezoelectric-related fields, especially under demanding or extreme conditions.

Zirconia doped glasses are ideal for biomedical applications owing to their improved mechanical strength, non-toxicity and biocompatibility. Herein, ZrO2 doped BaO-SiO2- TiO2 (BST) based glasses within the system (30–x)BaO.40SiO2.30TiO2.xZrO2 (0≤x;≤6) were fabricated using a melt-quenching technique. X-ray diffraction (XRD) measurements confirmed the non-crystalline nature of the glass samples. Density of the glasses increased from 3.538 to 3.802 g/cm3. Fourier transform infrared (FTIR) spectroscopy was employed to examine the structural or bonding mechanism. Further, mechanical performance of the glass pellets was studied using a universal testing machine (UTM) in compression mode, showing that the compressive strength increased with higher ZrO2 content, from 20.4 to 222 MPa of the glasses. Cell viability using 3-(4,5-dimethyl-2- yl)-2,5-diphenyltetrazolium bromide (MTT) assays on the human osteoblastic cell line (MG-63) revealed no cytotoxic effects on osteoblast cells, and maintaining cell viability even at higher concentrations. Additionally, cell cytotoxicity was evaluated using trypan blue assay and DAPI (4,6-diamidino-2-phenylindole) staining on glass samples. Therefore, the present study uniquely demonstrates that systematic ZrO2 incorporation into BaO-SiO2-TiO2 glass matrices markedly enhances both mechanical strength and biological activity, establishing a new class of bioactive glass compositions with simultaneous structural and biomedical advantages for bone regeneration applications.

ABSTRACT A comprehensive bibliometric analysis of sodium potassium niobate (K0.5Na0.5NbO3, KNN)-based piez oelectric materials, highlighting the significant adv ancements and research trends in the field over the past two decades has been conducted in this study. KNN has emerged as a promising lead-free alternative to traditional lead- based piezoelectric ceramics like lead zirconate titanate (PZ T), accounting for env ironmental concerns. Analy sis was conducted using the Scopus database, circumscribing 1,620 publications from year 2003 to 2025, revealing key themes such as phase boundary engineering, doping effects and microstructural optimization that enhance KNN's piezoelectric properties. The results indicate a dramatic increase in global research output, indicating a shift towards sustainable piezoelectric materials. Key contributors and influential papers are identified, showcasing the collaborative efforts in this rapidly evolving field. This bibliometric study maps the current landscape of KNN research. It provides insights into future directions, emphasiz ing the importance of continued innovation and collaboration in developing high-performance lead-free piezoelectric devices.

Substoichiometric titanium oxides, particularly M agnéli phases (TinO2n–1, n=3-10), exhibit promising properties for various functional applications. However, achieving high-quality M agnéli phase (Ti4O7) thin films at room temperature remains a significant challenge due to limitations in conventional deposition techniques. In this study, we report the successful room temperature fabrication of pure Ti4O7 thin films on glass substrates using a sol-gel spin coating approach. Structural, optical, morphological, elemental, luminescence and photocatalytic properties of the films were systematically investigated by varying precursor concentrations (1 and 4 mmol). Structural analysis confirmed the formation of anorthic crystal structure of Ti4O7 without any secondary phase. Optical studies revealed bandgap variations (2.08 and 3.75 eV) attributed to differences in film thickness. Photocatalytic performance, assessed through methylene blue dye degradation under visible light, demonstrated enhanced activity for the 1 mmol film, achieving a degradation efficiency of 72% and a rate constant of 3.3036 × 10–3 min–1. This work offers a feasible chemical solution sol-gel technique to overcome room temperature deposition limitations of M agnéli phases, and opening new possibilities for their integration into photocatalytic and optoelectronic applications.

ABSTRACT In the present work, a novel Z rC precursor, namely polyzirconoxanesal containing vinyl groups, was successfully synthesized by a simple one-pot synthesis, with zirconium n-propoxide (Z r(OC3H7)4), methacrylic anhydride and dihydroxy benzene as starting materials. T he obtained single-source-precursor was powdered and named as Z M D, which shows excellent solubility in solv ents such as alcohol, acetone, N,N-dimethylformamide, tetrahy drofuran, toluene, etc. T he Z M D was characterized by Fourier transform infrared (FTIR) spectroscopy to confirm the structure units such as Z r-O-C, C=O and C=C. The polymer-to-ceramic transfor- mation was investigated by thermogravimetric analysis and FTIR. Due to the fact that the vinyl groups are involved in the cross-linking, the Z M D possesses good ceramic yield, such as ca. 50 wt% at 1200°C and ca. 40 wt% at 1500°C. The phase composition and microstructure of obtained ceramics were studied by X-ray diffraction, elemental analysis and transmission electron microscopy. The results show that the ZrO2 was first formed and then transformed into Z rC at 1500°C. In gen eral, the gra in si z e o f obt aine d Z rC powders is b elow 100 nm, which is significantly influenced by the in-situ formed free carbon. Based on the simple synthesis route, excellent solubility and high ceramic yield, the present ZM D has to be considered as promising precursors for ultrahigh temperature resistance Z rC, which opens a new window for potential fabrication of ultrahigh temperature ceramic matrix composites by precursor infiltration py rolysis process.

Porcelain insulators are essential for ensuring overhead transmission lines’ mechanical and electrical reliability, particularly in ultra high voltage (UHV) systems. However, manufacturing defects can compromise their performance under operational stresses. The internal hydraulic pressure test is a critical method for enhancing the mechanical reliability of porcelain insulators. This study examines the effects of gasket positioning, seal contact force, and contact location on stress concentration during hydrostatic testing and discusses the methodology for selecting the optimal hydraulic pressure load. Finite element simulations reveal that these factors significantly influence stress distribution, particularly near the neck, where excessive stress may lead to structural failure. Statistical analysis using the Weibull distribution suggests that the optimal hydraulic pressure load should be chosen within a transition range to effectively eliminate defective components while preventing excessive damage to insulators. These findings provide theoretical guidance for optimizing hydrostatic testing procedures, ultimately improving the reliability and performance of porcelain insulators in high-voltage applications.

This article pr es ents a study o n t he synthesis and characterization of Ca2.5Ag0.3Pr0.2Co4O9, ap-type semiconducting material, to evaluate its potential for thermoelectric generator applications. The material is designed by partially substituting calcium in the Ca3Co4O9 matrix with Ag and Pr, aiming to enhance its thermoelectric performance using improved electrical conductivity and Seebeck coefficient. The material is synthesized through a sol-gel method, followed by extensive structural and morphological characterization through differential thermal analysis- thermogravimetry (DTA-TG), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and TM devices. Thermoelectric properties, including electrical resistivity, Seebeck coefficient and thermal conductivity, are systematically measured to calculate the material’s figure of merit. The doping of Ag and Pr leads to an optimized balance between electrical and thermal transport properties, making Ca2.5Ag0.3Pr0.2Co4O9 a strong candidate for high-temperature thermoelectric applications, particularly for waste heat recovery and power generation. The findings from this study demonstrate the material’s potential for enhancing the efficiency of thermoelectric generators used in challenging operational environments.

ABSTRACT Using the spray pyrolysis technique, this study presents the characteristics of CoFeS2 and NiFeS2 thin films prepared on glass substrate, including their structure, morphological, chemical composition and optical properties. X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy were used to analyze the obtained thin films. The results of the investigations showed a hexagonal phase and a cubic structure with crystallite size equal to 88 and 86 nm for CoFeS2 and NiFeS2, respectively. SEM images presented tightly packed thin films containing granular grains with grain size between 10 and 30 nm. It was pointed out that the first material with p type and a gap energy of the order of 1.49±0.05 eV, which matches well the maximum of the solar spectrum, can play the role of an absorber in solar photopile. On the contrary, the second material can serve, with its n type semiconductor and its gap energy of 2.49±0.05 eV, as a buffer layer in a standard solar cell such as NiFeS2 (n) / CoFeS2 (p). Such solar cells based on ternary sulfide may be of interest to serve as an important device in various sensitivity applications.

This study investigates the influence of niobium nitride (NbN) particle reinforcement on the microstructure and mechanical properties of mullite-carbon fiber (CF) composites fabricated via spark plasma sintering. Two composite formulations were prepared: mullite-1 wt% CF and mullite-10 wt% NbN-1 wt% CF. The raw materials were mixed using wet milling and sintered at 1350oC under vacuum (15-25 Pa) with an initial and final applied pressure of 10 and 50 MPa, respectively. Densification analysis confirmed that both composites achieved relative densities exceeding 99% of the theoretical value. X-ray diffraction analysis identified mullite and NbN as the only crystalline phases. M icrostructural evaluations using field emission scanning electron microscopy revealed a uniform three-dimensional distribution of CFs, with additional uniform dispersion of NbN particles in the hy brid composite. T he incorporation of NbN significantly enhanced mechanical properties, yielding a bending strength of 506±28 M Pa, Vickers hardness of 17.27±0.35 GPa, and fracture toughness of 7.42±0.27 M Pa.m1/2. The results demonstrate that hybrid reinforcement with NbN particles effectively improves the mechanical performance of mullite-CF composites, making them promising candidates for high-performance structural applications. The CF pull-out effect and the crack deflection by NbN particles were the main factors improving the fracture toughness and bending strength.

Vanadium dioxide (VO2) films exhibit excellent thermochromic behaviour, altering its thermal, optical and electrical properties near 68°C through a phase transition. This study explores how film thickness impacts these characteristics across transition temperature (τc), providing new insights into its semiconductor-metal transition (SMT). VO2 films were fabricated on quartz substrates via electron-beam evaporation followed by precise oxygen annealing. Differential scanning calorimetry (DSC) confirmed the phase transition through observable endothermic peaks. DSC data showed a drop of τc from nearly 67° to 64°C. Optical measurements showed a thickness-dependent τc, decreasing from nearly 67° to 56°C, while electrical measurements showcased a similar trend from nearly 63° to 55°C, with decreasing thickness of the films. Capacitance studies further rev ealed increased charge carrier generation during the SM T, highlighting thickness as a crucial factor in optimizing VO2 for smart material specific applications.