Search Results (500)

In this study, Hf_0.5Zr_0.5O₂ (HZO) thin-films were deposited using a Co-plasma atomic layer deposition (CPALD) process that combined both remote plasma and direct plasma, for the development of ferroelectric memory devices. Ferroelectric capacitors with a symmetric hybrid TiN/W/HZO/W/TiN electrode structure, incorporating W electrodes as insertion layers, were fabricated. Rapid thermal annealing (RTA) was subsequently employed to control the crystalline phase of the films. The electrical and structural properties of the capacitors were analyzed based on the RTA temperature, and the presence, thickness, and position of the W insertion electrode layer. Consequently, the capacitor with 5 nm-thick W electrode layers inserted on both the top and bottom sides and annealed at 700 °C exhibited the highest remnant polarization (2P_r = 61.0 μC/cm²). Moreover, the symmetric hybrid electrode capacitors annealed at 500–600 °C also exhibited high 2P_r values of approximately 50.4 μC/cm², with a leakage current density of approximately 4 × 10⁻⁵ A/cm² under an electric field of 2.5 MV/cm. The findings of this study are expected to contribute to the development of electrode structures for improved performance of HZO-based ferroelectric memory devices. Full article

This paper presents the results of a comprehensive study of the structure, phase composition, thermal corrosion, and tribological properties of multilayer gradient coatings based on YSZ/NiCrAlY obtained using detonation spraying. X-ray phase analysis showed that the coatings consist entirely of metastable tetragonal zirconium dioxide (t’-ZrO₂) phase stabilized by high temperature and rapid cooling during spraying. SEM analysis confirmed the multilayer gradient phase distribution and high density of the structure. Wear resistance, optical profilometry, wear quantification, and coefficient of friction measurements were used to evaluate the operational stability. The results confirm that the structural parameters of the coating, such as porosity and phase gradient, play a key role in improving its resistance to thermal corrosion and CMAS melt, which makes such coatings promising for use in high-temperature applications. It is shown that a dense and thick coating effectively prevents the penetration of aggressive media, providing a high barrier effect and minimal structural damage. Tribological tests in the temperature range from 21 °C to 650 °C revealed that the best characteristics are observed at 550 °C: minimum coefficient of friction (0.63) and high stability in the stage of stable wear. At room temperature and at 650 °C, there is an increase in wear due to the absence or destabilization of the protective layer. Full article

After reviewing the state of the art of the fluorination of inorganic solid electrolytes, an application of gas/solid fluorination is given and how it can be processed. Garnet-type oxide has been chosen. These oxides with an ideal structure of chemical formula A₃B₂(XO₄)₃ are mainly known for their magnetic and dielectric properties. Certain garnets may have a high enough Li⁺ ionic conductivity to be used as solid electrolyte of lithium ion battery. The surface of LLZO may be changed in contact with the moisture and CO₂ present in the atmosphere that results in a change of the conductivity at the interface of the solid. LiOH and/or lithium carbonate are formed at the surface of the garnet particles. In order to allow for handling and storage under normal conditions of this solid electrolyte, surface fluorination was performed using elemental fluorine. When controlled using mild conditions (temperature lower or equal to 200 °C, either in static or dynamic mode), the addition of fluorine atoms to LLZO with Li_6,4Al_0,2La₃Zr₂O₁₂ composition is limited to the surface, forming a covering layer of lithium fluoride LiF. The effect of the fluorination was evidenced by IR, Raman, and NMR spectroscopies. If present in the pristine LLZO powder, then the carbonate groups disappear. More interestingly, contrary to the pristine LLZO, the contents of these groups are drastically reduced even after storage in air up to 45 days when the powder is covered with the LiF layer. Surface fluorination could be applied to other solid electrolytes that are air sensitive. Full article

Fully printable carbon-based multiporous layered electrode perovskite solar cells (MPLE−PSCs) are close to being commercialized due to their excellent stability, their ability to easily be scaled up, and their amenability to mass production via non-vacuum fabrication processes. To improve their efficiency, it is important that detailed studies of the morphologies of mesoporous electrodes be carried out. In this study, we prepared five types of ZrO₂ spacer layers for MPLE−PSCs, and the morphology of ZrO₂ and device performance were evaluated using a scanning electron microscope, nitrogen adsorption/desorption measurements, electrode resistance measurements, UV-visible light reflectance measurements, and current density–voltage measurements. The results reveal that the adequate specific surface area and pore size distribution of mesoporous ZrO₂ provided high insulation ability when used as spacers between electrodes and light absorbance, resulting in a 10.92% photoelectric conversion efficiency with a 23.22 mA cm⁻² short-circuit current density. This information can serve as a guideline for designing morphologies useful for producing high-efficiency devices. Full article

Background/Objectives: The increasing demand for aesthetics in dentistry has driven significant advancements in both materials and techniques. The primary cause of ceramic detachment in dental restorations is extensive mechanical stress, which often results in detachment and clinical complications. This study aims to improve the bond strength between NiCr-based metal frameworks and ceramic coatings by introducing biocompatible inorganic MeSiON thin films (Me = Cr or Zr) as interlayers. Methods: MeSiON coatings with a thickness of ~2 μm were deposited on NiCr alloy using cathodic arc evaporation. To tailor the stoichiometry, morphology, and mechanical properties of the coatings, the substrate bias voltage was varied: −50 V, −100 V, −150 V, −200 V. Structural and surface characterization was performed using SEM/EDS, XRD, profilometry, and contact angle analysis. The coating adhesion was evaluated by using standardized scratch testing, while the bond strength was evaluated using a three-point bending test. Results: The NiCr alloy exhibited a dendritic microstructure, and the ceramic layer consisted mainly of quartz, feldspar, kaolin, and ZrO₂. ZrSiON coatings showed superior roughness, elemental incorporation, and adhesion compared to Cr-based coatings, these properties being further improved by increasing the substrate bias. The highest bond strength was achieved with a ZrSiON coating deposited at −200 V, a result we attributed to increased surface roughness and mechanical interlocking at the ceramic-metal interface. Conclusions: CrSiON and ZrSiON interlayers enhanced ceramic-to-metal adhesion in NiCr-based dental restorations. The enhancement in bond strength is primarily ascribed to substrate bias-induced modifications in the coating’s stoichiometry, roughness, and adhesion. Full article

The aim of this work was the preparation of ceramic monolithic catalysts for the catalytic oxidation of gaseous mixture of benzene, toluene, ethylbenzene and o-xylene BTEX. The possibility of using zirconium dioxide (ZrO₂) as a filament for the fabrication of 3D-printed ceramic monolithic carriers was investigated using fused filament fabrication. A mixed manganese and iron oxide, MnFeO_x, was used as the catalytically active layer, which was applied to the monolithic substrate by wet impregnation. The approximate geometric surface area of the obtained carrier was determined to be 53.4 cm², while the mass of the applied catalytically active layer was 50.3 mg. The activity of the prepared monolithic catalysts for the oxidation of BTEX was tested at different temperatures and space times. The results obtained were compared with those obtained with commercial monolithic catalysts made of ceramic cordierite with different channel dimensions, and with monolithic catalysts prepared by stereolithography. In the last part of the work, a kinetic analysis and the modeling of the monolithic reactor were carried out, comparing the experimental results with the theoretical results obtained with the 1D pseudo-homogeneous and 1D heterogeneous models. Although both models could describe the investigated experimental system very well, the 1D heterogeneous model is preferable, as it takes into account the heterogeneity of the reaction system and therefore provides a more realistic description. Full article

Using low-cost transition-metal chlorides and furfuryl alcohol as raw materials, the (TiZrHfNbTa)C precursor was prepared, and a three-dimensional braided carbon fiber preform (C/C) coated with pyrolytic carbon (PyC) was used as the reinforcing material. A C/C-(TiZrHfNbTa)C composite was successfully fabricated through the precursor impregnation pyrolysis (PIP) process. Under extreme oxyacetylene ablation conditions (2311 °C/60 s), this composite material demonstrated outstanding ablation resistance, with a mass ablation rate as low as 0.67 mg/s and a linear ablation rate of only 20 μm/s. This excellent performance can be attributed to the dense (HfZr)₆(TaNb)₂O₁₇ oxide layer formed during ablation. This oxide layer not only has an excellent anti-erosion capability but also effectively acts as an oxygen diffusion barrier, thereby significantly suppressing further ablation and oxidation within the matrix. This study provides an innovative strategy for the development of low-cost ultra-high-temperature ceramic precursors and opens up a feasible path for the efficient preparation of C/C-(TiZrHfNbTa)C composites. Full article

The effect of induction heating on alumina ceramics and alumina ceramic composites based on α-Al₂O₃ nanopowders (additives: SiC, Si₃N₄, SiO₂, ZrO₂) has been examined. Various factors such as the structure, grain size, distribution of elements, hardness, fracture toughness, and wear rate of hot-pressed ceramic materials were assessed. Despite achieving improved densification of alumina ceramics at a higher temperature of 1720 °C, there is a consistent trend toward a decline in hardness and fracture toughness. Heating at lower temperatures of 1300–1500 °C results in the development of a strengthened surface layer with a fine-grained structure enriched with carbon. Therefore, the wear rate behavior of such ceramics differs from the behavior of samples made at higher temperatures of 1600–1720 °C. This fact indicates the presence of a non-thermal microwave effect of induction heating. The incorporation of additives to alumina leads to the formation of novel structures with altered crack propagation patterns. The optimal ceramic composite, containing 5 wt. % SiC, displayed superior hardness and the lowest wear rate when compared to pure alumina ceramics. Across all investigated composites, a short dwell time at 1700 °C results in an enhancement of the mechanical properties. Full article

BaTiO₃-based lead-free ferroelectric films with a large recoverable energy density (W_rec) and a high energy efficiency (η) are crucial components for next-generation dielectric capacitors, which are used in energy conditioning and storage applications in integrated circuits. In this study, grain-engineered (Ba_0.95,Sr_0.05)(Zr_0.2,Ti_0.8)O₃ (BSZT) ferroelectric thick films (~500 nm) were prepared on Si substrates. These films were deposited at 350 °C, 100 °C lower than the temperature at which the LaNiO₃ buffer layer was deposited on Pt/Ti. This method reduced the (001) grain population due to a weakened interface growth mode, while promoting volume growth modes that produced (110) and (111) grains with a high polarizability. As a result, these films exhibited a maximum polarization of ~88.0 μC/cm², a large W_rec of ~203.7 J/cm³, and a high energy efficiency η of 81.2% (@ 6.4 MV/cm). The small-field dielectric constant nearly tripled as compared with that of the same BSZT/LaNiO₃ heterostructure deposited at the same temperature (350 °C or 450 °C). The enhanced linear dielectric response, delayed ferroelectric polarization saturation, and increased dielectric strength due to the nano-grain size, collectively contributed to the improved energy storage performance. This work provides a novel approach for fabricating high-performance dielectric capacitors for energy storage applications. Full article

The synthesis and characterization of MgO-ZrO₂ heterostructures are examined in this work. To promote the creation of nanowires, the Si substrate is first covered with a catalyst layer of various Au thicknesses. Sputtering is used to achieve this deposition. After that, chemical vapor deposition (CVD) with a Au catalyst layer is used to create MgO nanowire arrays on the silicon substrate. Second, MgO/ZrO₂ Core–shell Nanowire Arrays are created by applying ZrO₂ layers to the surface of MgO nanowires of different diameters using chemical vapor deposition (CVD) procedures. The presence of both magnesium oxide (MgO) and zirconium dioxide (ZrO₂) in their oxidized forms was shown by the detailed characterization of the MgO-ZrO₂ core–shell nanowire samples utilizing a variety of methods. Phase formation, mechanical homogeneity, optical characteristics, and topographical structure and roughness were all thoroughly examined at various stresses. MgO hardness values ranged from 1.4 to 3.2 GPa, whereas MgO-ZrO₂ ranged from 0.38 to 1.2 GPa. The I–V parameter study was a further step in the examination of the heterostructure’s electrical properties. The structural, morphological, optical, mechanical, and electrical properties of the MgO-ZrO₂ heterostructure were all thoroughly described using these techniques. Full article

Combinatorial magnetron sputtering and electrical characterization were used to systematically study the impact of compositional changes in the resistive switching of transition metal oxides, specifically the Zr_xTa_1−xO_y system. Current-voltage behavior across a range of temperatures provided insights into the mechanisms that contribute to differences in the electrical conductivity of the pristine Ta₂O₅ and ZrO₂, and mixed Zr_xTa_1−xO_y devices. The underlying conductive mechanism was found to be a mixture of charge trapping and ionic motion, where charge trapping/emission dictated the short-term cycling behavior while ion motion contributed to changes in the conduction with increased cycling number. ToF-SIMS was used to identify the origin of the “wake-up” behavior of the devices, revealing an ionic motion contribution. This understanding of how cation concentration affects conduction in mixed valence systems helps provide a foundation for a new approach toward manipulating resistive switching in these active layer materials. Full article

The current review examines various methods for preparing photocatalytic materials based on ceramic substrates, with a focus on incorporating metal oxides such as ZnO, CuO, and MgO. This study compares traditional mixing, co-precipitation, sol–gel, and autoclave methods for synthesizing these materials. Kaolin-based ceramics (DD3 and DD3 with 38% ZrO₂) from Guelma, Algeria, were used as substrates. This review highlights the effects of different preparation methods on the structural, morphological, and compositional properties of the resulting photocatalysts. Additionally, the potential of these materials for the photocatalytic degradation of organic dyes, specifically Orange II, was evaluated. Results indicated that ceramic/ZnO/CuO and ceramic/MgO powders prepared via traditional mixing and co-precipitation techniques exhibited significantly faster degradation rates under visible light than Cu layers deposited on ceramic substrates using solution gradient processes. This enhancement was attributed to the increased effective surface area and the size of the spherical nanoparticles obtained through these methods, which facilitated accelerated pollutant absorption. This study highlights the ease and cost-effectiveness of preparing robust layers on ceramic substrates, which are advantageous for photocatalytic applications due to their straightforward removal after filtration. Notably, DD3Z/MgO powders demonstrated superior catalytic activity, achieving complete degradation of the organic dye in just 10 min, whereas DD3Z/ZnO-CuO powders achieved 93.6% degradation after 15 min. Additionally, experiments using kaolin-based ceramics as substrates instead of powders yielded a maximum dye decomposition rate of 77.76% over 6 h using ZnO thin layers prepared via the autoclave method. Full article

The polarization fatigue of PbZr_1−xTi_xO₃ (PZT) films is one of the most serious failure issues in their practical application. In the present work, Ba_0.3Sr_0.7Zr_0.18Ti_0.82O₃ (BSZT) was used as an inserting layer to improve the polarization fatigue of PbZr_0.50Ti_0.50O₃ thick film. PZT thick films and BSZT layers were deposited via magnetron sputtering technology. The effects of BSZT layer on the dielectric response, remanent polarization, and fatigue resistance of PZT thick films were investigated experimentally. The results showed that the dielectric constant increased from 457 to 880 (1 MHz), and the reversible/irreversible Rayleigh coefficients were also enhanced. The remanent polarization P_r of the PZT thick films increased from 37 μC/cm² to 42.4 μC/cm². After a 1.08 × 10⁹ cycles polarization fatigue test, the ferroelectric polarization loss was 9% for the PZT thick film at 368 kV/cm. The reversible/irreversible Rayleigh coefficients had a very small decline, of only 5% and 2%, respectively. This demonstrates that, different from the previously reported buffer layers, BSZT buffer layers can simultaneously enhance the dielectric and ferroelectric properties and improve the polarization fatigue of PZT thick films. Full article

This work systematically analyses the electrical and structural properties of a bilayer gate dielectric composed of Sm₂O₃ and ZrO₂ on a 4H-SiC substrate. The bilayer thin film was fabricated using a sputtering process, followed by a dry oxidation step with an adjusted oxygen-to-nitrogen (O₂:N₂) gas concentration ratio. XRD analysis validated formation of an amorphous structure with a monoclinic phase for both Sm₂O₃ and ZrO₂ dielectric thin films. High-resolution transmission emission (HRTEM) analysis verified the cross-section of fabricated stacking layers, confirmed physical oxide thickness around 12.08–13.35 nm, and validated the amorphous structure. Meanwhile, XPS confirmed the presence of more stoichiometric dielectric oxide formation for oxidized/nitrided O₂:N₂-incorporated samples, and more sub-stochiometric thin films for samples only oxidized in ambient O₂. The oxidation/nitridation processes with N₂ incorporation influenced the band offsets and revealed conduction band offsets (CBOs) ranging from 2.24 to 2.79 eV. The affected charge movement and influenced electrical performance where optimized samples with gas concentration ratio of 90% O₂:10% N₂ achieved the highest electrical breakdown field of 10.1 MV cm⁻¹ at a leakage current density of 10⁻⁶ A cm⁻². This gate stack also improved key parameters such as the effective dielectric constant ($k_{eff}$) up to 29.75, effective oxide charge ($Q_{eff}$), average interface trap density ($D_{it}$), and slow trap density (STD). The bilayer gate stack of Sm₂O₃ and ZrO₂ revealed potential attractive characteristics as a candidate for high-k gate dielectric applications in metal-oxide-semiconductor (MOS)-based devices. Full article

This study investigates the role of Al alloying in tailoring the oxidation resistance of AlTiCrZrNbTa refractory high-entropy alloy (RHEA) coatings on Zry-4 substrates under high-temperature steam environments. Coatings with varying Al contents (0–25 at.%) were deposited via magnetron sputtering and subjected to oxidation tests at 1000–1100 °C. The results demonstrate that Al content critically governs oxidation kinetics and coating integrity. The optimal performance was achieved at 10 at.% Al, above which a dense, continuous composite oxide layer (Al₂O₃, TiO₂, Cr₂O₃) formed, effectively suppressing oxygen penetration and maintaining strong interfacial adhesion. Indentation tests confirmed enhanced mechanical integrity in Al-10 coatings, with minimal cracking post-oxidation. Excessive Al alloying (≥17 at.%) led to accelerated coating oxidation. This work establishes a critical Al threshold for balancing oxidation and interfacial bonding, providing a design strategy for developing accident-tolerant fuel cladding coatings. Full article