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Search Results (1,269)

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Keywords = TiN film

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14 pages, 2905 KiB  
Article
Optimal Design of a Lightweight Terahertz Absorber Featuring Ultra-Wideband Polarization-Insensitive Characteristics
by Yafeng Hao, Tengteng Li, Pu Zhu, Fupeng Ma, Huijia Wu, Cheng Lei, Meihong Liu, Ting Liang and Jianquan Yao
Photonics 2025, 12(8), 787; https://doi.org/10.3390/photonics12080787 - 4 Aug 2025
Viewed by 197
Abstract
Metamaterial absorbers in terahertz (THz) based bands have garnered significant attention for their potential applications in military stealth, terahertz imaging, and other fields. Nevertheless, the limited bandwidth, low absorption rate, and heavy weight greatly reduce the further development and wide application of terahertz [...] Read more.
Metamaterial absorbers in terahertz (THz) based bands have garnered significant attention for their potential applications in military stealth, terahertz imaging, and other fields. Nevertheless, the limited bandwidth, low absorption rate, and heavy weight greatly reduce the further development and wide application of terahertz absorbers. To solve these problems, we propose a polystyrene (PS)-based ultra-broadband metamaterial absorber integrated with a polyethylene terephthalate (PET) double-sided adhesive layer and a patterned indium tin oxide (ITO) film through the simulation method, which operates in the THz band. The electromagnetic wave absorption properties and underlying physical absorption mechanisms of the proposed metamaterial absorbers are comprehensively modeled and rigorously numerically simulated. The research demonstrates the metamaterial absorber can achieve absorption performance of over 90% for fully polarized incident waves in the ultra-wideband range of 1.2–10 THz, especially achieving perfect absorption characteristics of over 99.9% near 1.8–1.9 THz and 5.8–6.2 THz. The proposed absorber has a lightweight physical property of 0.7 kg/m2 and polarization-insensitive characteristic, and it achieves a broad-angle that allows a range of incidence angles up to 60°. The simulation research results of this article provide theoretical support for the design of terahertz absorbers with ultra-wideband absorption characteristics. Full article
(This article belongs to the Special Issue Metamaterials and Nanophotonics: Fundamentals and Applications)
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13 pages, 3623 KiB  
Article
Fabrication and Characterization of Ferroelectric Capacitors with a Symmetric Hybrid TiN/W/HZO/W/TiN Electrode Structure
by Ha-Jung Kim, Jae-Hyuk Choi, Seong-Eui Lee, So-Won Kim and Hee-Chul Lee
Materials 2025, 18(15), 3547; https://doi.org/10.3390/ma18153547 - 29 Jul 2025
Viewed by 270
Abstract
In this study, Hf0.5Zr0.5O2 (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 [...] Read more.
In this study, Hf0.5Zr0.5O2 (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 (2Pr = 61.0 μC/cm2). Moreover, the symmetric hybrid electrode capacitors annealed at 500–600 °C also exhibited high 2Pr 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
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22 pages, 5670 KiB  
Article
Tailoring TiO2/TiN Bi-Layer Interfaces via Nitrogen Diffusion and Gold Functionalization for Advanced Photocatalysis
by Jelena P. Georgijević, Tijana Stamenković, Tijana Đorđević, Danilo Kisić, Vladimir Rajić and Dejan Pjević
Catalysts 2025, 15(8), 701; https://doi.org/10.3390/catal15080701 - 23 Jul 2025
Viewed by 457
Abstract
100 nm thick TiO2/TiN bilayers with varying thickness ratios were deposited via reactive sputtering of a Ti target in controlled oxygen and nitrogen atmospheres. Post-deposition annealing in air at 600 °C was performed to induce nitrogen diffusion through the oxygen-deficient TiO [...] Read more.
100 nm thick TiO2/TiN bilayers with varying thickness ratios were deposited via reactive sputtering of a Ti target in controlled oxygen and nitrogen atmospheres. Post-deposition annealing in air at 600 °C was performed to induce nitrogen diffusion through the oxygen-deficient TiO2 layer. The resulting changes in morphology and chemical environment were investigated in detail using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis spectroscopy. Detailed TEM and XPS analyses have confirmed nitrogen diffusion across the TiO2 layer, with surface nitrogen concentration and the ratio of interstitial to substitutional nitrogen dependent on the TiO2/TiN mass ratio. Optical studies demonstrated modifications in optical constants and a reduction of the effective bandgap from 3.2 eV to 2.6 eV due to new energy states introduced by nitrogen doping. Changes in surface free energy induced by nitrogen incorporation showed a correlation to nitrogen doping sites on the surface, which had positive effects on overall photocatalytic activity. Photocatalytic activity, assessed through methylene blue degradation, showed enhancement attributed to nitrogen doping. Additionally, deposition of a 5 nm gold layer on the annealed sample enabled investigation of synergistic effects between nitrogen doping and gold incorporation, resulting in further improved photocatalytic performance. These findings establish the TiO2/TiN bilayer as a versatile platform for supporting thin gold films with enhanced photocatalytic properties. Full article
(This article belongs to the Special Issue Recent Advances in Photocatalysis for Environmental Applications)
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14 pages, 2646 KiB  
Article
Analog Resistive Switching Phenomena in Titanium Oxide Thin-Film Memristive Devices
by Karimul Islam, Rezwana Sultana and Robert Mroczyński
Materials 2025, 18(15), 3454; https://doi.org/10.3390/ma18153454 - 23 Jul 2025
Viewed by 376
Abstract
Memristors with resistive switching capabilities are vital for information storage and brain-inspired computing, making them a key focus in current research. This study demonstrates non-volatile analog resistive switching behavior in Al/TiOx/TiN/Si(n++)/Al memristive devices. Analog resistive switching offers gradual, controllable [...] Read more.
Memristors with resistive switching capabilities are vital for information storage and brain-inspired computing, making them a key focus in current research. This study demonstrates non-volatile analog resistive switching behavior in Al/TiOx/TiN/Si(n++)/Al memristive devices. Analog resistive switching offers gradual, controllable conductance changes, which are essential for mimicking brain-like synaptic behavior, unlike digital/abrupt switching. The amorphous titanium oxide (TiOx) active layer was deposited using the pulsed-DC reactive magnetron sputtering technique. The impact of increasing the oxide thickness on the electrical performance of the memristors was investigated. Electrical characterizations revealed stable, forming-free analog resistive switching, achieving endurance beyond 300 DC cycles. The charge conduction mechanisms underlying the current–voltage (I–V) characteristics are analyzed in detail, revealing the presence of ohmic behavior, Schottky emission, and space-charge-limited conduction (SCLC). Experimental results indicate that increasing the TiOx film thickness from 31 to 44 nm leads to a notable change in the current conduction mechanism. The results confirm that the memristors have good stability (>1500 s) and are capable of exhibiting excellent long-term potentiation (LTP) and long-term depression (LTD) properties. The analog switching driven by oxygen vacancy-induced barrier modulation in the TiOx/TiN interface is explained in detail, supported by a proposed model. The remarkable switching characteristics exhibited by the TiOx-based memristive devices make them highly suitable for artificial synapse applications in neuromorphic computing systems. Full article
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15 pages, 7165 KiB  
Article
Structural and Performance Studies of Lanthanum–Nitrogen Co-Doped Titanium Dioxide Thin Films Under UV Aging
by Pengcheng Cao, Li Zhang and Yanbo Yuan
Micromachines 2025, 16(8), 842; https://doi.org/10.3390/mi16080842 - 23 Jul 2025
Viewed by 416
Abstract
In this study, lanthanum–nitrogen co-doped titanium dioxide (La-N-TiO2) thin films were fabricated using Ion Beam Assisted Deposition (IBAD) and subjected to accelerated ultraviolet (UV) aging experiments to systematically investigate the impact of co-doping on the films’ resistance to UV aging. X-ray [...] Read more.
In this study, lanthanum–nitrogen co-doped titanium dioxide (La-N-TiO2) thin films were fabricated using Ion Beam Assisted Deposition (IBAD) and subjected to accelerated ultraviolet (UV) aging experiments to systematically investigate the impact of co-doping on the films’ resistance to UV aging. X-ray diffraction (XRD) analysis revealed that La-N co-doping inhibits the phase transition from anatase to rutile, significantly enhancing the phase stability of the films. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) characterizations indicated that co-doping increased the density and surface uniformity of the films, thereby delaying the expansion of cracks and increase in roughness induced by UV exposure. Energy-dispersive X-ray spectroscopy (EDS) results confirmed the successful incorporation of La and N into the TiO2 lattice, enhancing the chemical stability of the films. Contact angle tests demonstrated that La-N co-doping markedly improved the hydrophobicity of the films, inhibiting the rapid decay of hydrophilicity during UV aging. After three years of UV aging, the co-doped films maintained high structural integrity and photocatalytic performance, exhibiting excellent resistance to UV aging. These findings offer new insights into the long-term stability of photovoltaic self-cleaning materials. Full article
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18 pages, 6673 KiB  
Article
Tribological Properties of MoN/TiN Multilayer Coatings Prepared via High-Power Impulse Magnetron Sputtering
by Jiaming Xu, Ping Zhang, Jianjian Yu, Puyou Ying, Tao Yang, Jianbo Wu, Tianle Wang, Nikolai Myshkin and Vladimir Levchenko
Lubricants 2025, 13(8), 319; https://doi.org/10.3390/lubricants13080319 - 22 Jul 2025
Viewed by 370
Abstract
To address the limitations of single-layer nitride coatings, such as poor load adaptability and low long-term durability, MoN/TiN multilayer coatings were prepared via high-power impulse magnetron sputtering (HiPIMS). HiPIMS produces highly ionized plasmas that enable intense ion bombardment, yielding nitride films with enhanced [...] Read more.
To address the limitations of single-layer nitride coatings, such as poor load adaptability and low long-term durability, MoN/TiN multilayer coatings were prepared via high-power impulse magnetron sputtering (HiPIMS). HiPIMS produces highly ionized plasmas that enable intense ion bombardment, yielding nitride films with enhanced mechanical strength, durability, and thermal stability versus conventional methods. The multilayer coating demonstrated a low coefficient of friction (COF, ~0.4) and wear rate (1.31 × 10−7 mm3/[N·m]). In contrast, both TiN and MoN coatings failed at 5 N and 10 N loads, respectively. Under increasing loads, the multilayer coating maintained stable wear rates (1.84–3.06 × 10−7 mm3/[N·m]) below 20 N, and ultimately failed at 25 N. Furthermore, the MoN layer contributes to COF reduction. Grazing-incidence X-ray diffraction analysis confirmed the enhanced crystallographic stability of the multilayer coating, thereby revealing a dominant (111) orientation. The multilayer architecture suppresses crack propagation while effectively balancing hardness and toughness, offering a promising design for extreme-load applications. Full article
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28 pages, 14374 KiB  
Article
Novel Airfoil-Shaped Radar-Absorbing Inlet Grilles on Aircraft Incorporating Metasurfaces: Multidisciplinary Design and Optimization Using EHVI–Bayesian Method
by Xufei Wang, Yongqiang Shi, Qingzhen Yang, Huimin Xiang and Saile Zhang
Sensors 2025, 25(14), 4525; https://doi.org/10.3390/s25144525 - 21 Jul 2025
Viewed by 351
Abstract
Aircraft, as electromagnetically complex targets, have radar cross-sections (RCSs) that are influenced by various factors, with the inlet duct being a critical component that often serves as a primary source of electromagnetic scattering, significantly impacting the scattering characteristics. In light of the conflict [...] Read more.
Aircraft, as electromagnetically complex targets, have radar cross-sections (RCSs) that are influenced by various factors, with the inlet duct being a critical component that often serves as a primary source of electromagnetic scattering, significantly impacting the scattering characteristics. In light of the conflict between aerodynamic performance and electromagnetic characteristics in the design of aircraft engine inlet grilles, this paper proposes a metasurface radar-absorbing inlet grille (RIG) solution based on a NACA symmetric airfoil. The RIG adopts a sandwich structure consisting of a polyethylene terephthalate (PET) dielectric substrate, a copper zigzag metal strip array, and an indium tin oxide (ITO) resistive film. By leveraging the principles of surface plasmon polaritons, electromagnetic wave absorption can be achieved. To enhance the design efficiency, a multi-objective Bayesian optimization framework driven by the expected hypervolume improvement (EHVI) is constructed. The results show that, compared with a conventional rectangular cross-section grille, an airfoil-shaped grille under the same constraints will reduce both aerodynamic losses and the absorption bandwidth. After 100-step EHVI–Bayesian optimization, the optimized balanced model attains a 57.79% reduction in aerodynamic loss relative to the rectangular-shaped grille, while its absorption bandwidth increases by 111.99%. The RCS exhibits a reduction of over 8.77 dBsm in the high-frequency band. These results confirm that the proposed optimization design process can effectively balance the conflict between aerodynamic performance and stealth performance for RIGs, reducing the signal strength of aircraft engine inlets. Full article
(This article belongs to the Section Electronic Sensors)
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13 pages, 3688 KiB  
Article
Layer-by-Layer Engineered Zinc–Tin Oxide/Single-Walled Carbon Nanotube (ZTO/SWNT) Hybrid Films for Thin-Film Transistor Applications
by Yong-Jae Kim, Young-Jik Lee, Yeon-Hee Kim, Byung Seong Bae and Woon-Seop Choi
Micromachines 2025, 16(7), 825; https://doi.org/10.3390/mi16070825 - 20 Jul 2025
Viewed by 547
Abstract
Indium-based oxide semiconductors have been commercialized because of their excellent electrical properties, but the high cost, limited availability, and environmental toxicity of indium necessitate the development of alternative materials. Among the most promising candidates, zinc–tin oxide (ZTO) is an indium-free oxide semiconductor with [...] Read more.
Indium-based oxide semiconductors have been commercialized because of their excellent electrical properties, but the high cost, limited availability, and environmental toxicity of indium necessitate the development of alternative materials. Among the most promising candidates, zinc–tin oxide (ZTO) is an indium-free oxide semiconductor with considerable potential, but its relatively low carrier mobility and inherent limitations in thin-film quality demand further performance enhancements. This paper proposes a new approach to overcome these challenges by incorporating single-walled carbon nanotubes (SWNTs) as conductive fillers into the ZTO matrix and using a layer-by-layer multiple coating process to construct nanocomposite thin films. As a result, ZTO/SWNTs (0.07 wt.%) thin-film transistors (TFTs) fabricated with three coating cycles exhibited a high saturation mobility of 18.72 cm2/V·s, a threshold voltage of 0.84 V, and a subthreshold swing of 0.51 V/dec. These values represent an approximately four-fold improvement in mobility compared to ZTO TFT, showing that the multiple-coating-based nanocomposite strategy can effectively overcome the fundamental limitations. This study confirms the feasibility of achieving high-performance oxide semiconductor transistors without indium, providing a sustainable pathway for next-generation flexible electronics and display technologies. Full article
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11 pages, 4974 KiB  
Article
Effect of Modulation Period on the Microstructure and Tribological Properties of AlCrTiVNbN/TiSiN Nano Multilayer Films
by Hongjuan Yan, Haoran Wang, Xiaona Li, Zhaoliang Dou and Fengbin Liu
Coatings 2025, 15(7), 839; https://doi.org/10.3390/coatings15070839 - 17 Jul 2025
Viewed by 275
Abstract
The impact of modulation periods on the microstructure, as well as the tribological and mechanical characteristics of the AlCrTiVNbN/TiSiN nano multilayer films, was investigated. The films were prepared with modulation periods ranging from 4 nm to 7 nm, and their properties were explored [...] Read more.
The impact of modulation periods on the microstructure, as well as the tribological and mechanical characteristics of the AlCrTiVNbN/TiSiN nano multilayer films, was investigated. The films were prepared with modulation periods ranging from 4 nm to 7 nm, and their properties were explored using X-ray diffraction (XRD), scanning electron microscope (SEM), nanoindentation, and a tribological tester. All nano multilayer films revealed a face-centered cubic (FCC) structure with a preferred planar direction of (200). As the modulation period increased, the XRD peak moved to higher angles, and the interplanar distance decreased. Also, the mechanical properties deteriorated, and the COF rose monotonically as a result. The nano multilayer film with a modulation period equal to 4 nm exhibited a smooth surface with minimal small particles, the highest hardness of 15.51 ± 0.16 GPa and elastic modulus of 182.89 ± 2.38 GPa, the highest values for the ratios of H/E and H3/E2, the lowest average friction coefficient of 0.73, and a wear rate equal to (8.2 9 ± 0.18) × 10−8 mm3·N−1·m−1. The improvement in the properties of the film was ascribed to the coherent growth and alternating stress field between the AlCrTiVNbN and TiSiN layers. Full article
(This article belongs to the Special Issue Surface Protection for Metal Materials)
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24 pages, 8373 KiB  
Article
Simple Strain Gradient–Divergence Method for Analysis of the Nanoindentation Load–Displacement Curves Measured on Nanostructured Nitride/Carbonitride Coatings
by Uldis Kanders, Karlis Kanders, Artis Kromanis, Irina Boiko, Ernests Jansons and Janis Lungevics
Coatings 2025, 15(7), 824; https://doi.org/10.3390/coatings15070824 - 15 Jul 2025
Viewed by 611
Abstract
This study investigates the fabrication, nanomechanical behavior, and tribological performance of nanostructured superlattice coatings (NSCs) composed of alternating TiAlSiNb-N/TiCr-CN bilayers. Deposited via High-Power Ion-Plasma Magnetron Sputtering (HiPIPMS) onto 100Cr6 steel substrates, the coatings achieved nanohardness values of ~25 GPa and elastic moduli up [...] Read more.
This study investigates the fabrication, nanomechanical behavior, and tribological performance of nanostructured superlattice coatings (NSCs) composed of alternating TiAlSiNb-N/TiCr-CN bilayers. Deposited via High-Power Ion-Plasma Magnetron Sputtering (HiPIPMS) onto 100Cr6 steel substrates, the coatings achieved nanohardness values of ~25 GPa and elastic moduli up to ~415 GPa. A novel empirical method was applied to extract stress–strain field (SSF) gradient and divergence profiles from nanoindentation load–displacement data. These profiles revealed complex, depth-dependent oscillations attributed to alternating strain-hardening and strain-softening mechanisms. Fourier analysis identified dominant spatial wavelengths, DWL, ranging from 4.3 to 42.7 nm. Characteristic wavelengths WL1 and WL2, representing fine and coarse oscillatory modes, were 8.2–9.2 nm and 16.8–22.1 nm, respectively, aligning with the superlattice period and grain-scale features. The hyperfine structure exhibited non-stationary behavior, with dominant wavelengths decreasing from ~5 nm to ~1.5 nm as the indentation depth increased. We attribute the SSF gradient and divergence spatial oscillations to alternating strain-hardening and strain-softening deformation mechanisms within the near-surface layer during progressive loading. This cyclic hardening–softening behavior was consistently observed across all NSC samples, suggesting it represents a general phenomenon in thin film/substrate systems under incremental nanoindentation loading. The proposed SSF gradient–divergence framework enhances nanoindentation analytical capabilities, offering a tool for characterizing thin-film coatings and guiding advanced tribological material design. Full article
(This article belongs to the Section Ceramic Coatings and Engineering Technology)
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12 pages, 3535 KiB  
Article
TiN-Ag Multilayer Protective Coatings for Surface Modification of AISI 316 Stainless Steel Medical Implants
by Božana Petrović, Dijana Mitić, Minja Miličić Lazić, Miloš Lazarević, Anka Trajkovska Petkoska, Ilija Nasov, Slavoljub Živković and Vukoman Jokanović
Coatings 2025, 15(7), 820; https://doi.org/10.3390/coatings15070820 - 14 Jul 2025
Viewed by 328
Abstract
Stainless steel (SS) is one of the materials most commonly utilized for fabrication of medical implants and its properties are often improved by deposition of protective coatings. This study investigates certain physico-chemical and biological properties of SS substrate coated with multilayer thin film [...] Read more.
Stainless steel (SS) is one of the materials most commonly utilized for fabrication of medical implants and its properties are often improved by deposition of protective coatings. This study investigates certain physico-chemical and biological properties of SS substrate coated with multilayer thin film consisting of titanium nitride and silver layers (TiN-Ag film). TiN-Ag films were deposited on the surface of AISI 316 SS substrate by a combination of cathodic arc evaporation and DC magnetron sputtering. SS substrate was analyzed by TEM, while deposited coatings were analyzed by SEM, EDS and wettability measurements. Also, mitochondrial activity assay, and osteogenic and chondrogenic differentiation were performed on dental pulp stem cells (DPSCs). SEM and EDS revealed excellent adhesion between coatings’ layers, with the top layer predominantly composed of Ag, which is responsible for antibacterial properties. TiN-Ag film exhibited moderately hydrophilic behaviour which is desirable for orthopedic implant applications. Biological assays revealed significantly higher mitochondrial activity and enhanced osteogenic and chondrogenic differentiation of DPSC on TiN-Ag films compared to TiN films. The newly designed TiN-Ag coatings showed a great potential for the surface modification of SS implants, and further detailed investigations will explore their suitability for application in clinical practice. Full article
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10 pages, 2813 KiB  
Article
The Effect of Doping with Aluminum on the Optical, Structural, and Morphological Properties of Thin Films of SnO2 Semiconductors
by Isis Chetzyl Ballardo Rodriguez, U. Garduño Terán, A. I. Díaz Cano, B. El Filali and M. Badaoui
J. Compos. Sci. 2025, 9(7), 358; https://doi.org/10.3390/jcs9070358 - 9 Jul 2025
Viewed by 333
Abstract
There is considerable interest in broadband nanomaterials, particularly transparent semiconductor oxides, within both fundamental research and technological applications. Historically, it has been considered that the variation in dopant concentration during the synthesis of semiconductor materials is a crucial factor in activating and/or modulating [...] Read more.
There is considerable interest in broadband nanomaterials, particularly transparent semiconductor oxides, within both fundamental research and technological applications. Historically, it has been considered that the variation in dopant concentration during the synthesis of semiconductor materials is a crucial factor in activating and/or modulating the optical and structural properties, particularly the bandgap and the parameters of the unit cell, of semiconductor oxides. Recently, tin oxide has emerged as a key material due to its excellent structural properties, optical transparency, and various promising applications in optoelectronics. This study utilized the ultrasonic spray pyrolysis technique to synthesize aluminum-doped tin oxide (ATO) thin films on quartz and polished single-crystal silicon substrates. The impact of varying aluminum doping levels (0, 2, 5, and 10 at. %) on morphology and structural and optical properties was examined. The ATO thin films were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmittance spectroscopy. SEM images demonstrated a slight reduction in the size of ATO nanoparticles as the aluminum doping concentration increased. XRD analysis revealed a tetragonal crystalline structure with the space group P42/mnm, and a shift in the XRD peaks to higher angles was noted with increasing aluminum content, indicating a decrease in the crystalline lattice parameters of ATO. The transmittance of the ATO films varied between 75% and 85%. By employing the transmittance spectra and the established Tauc formula the optical bandgap values of ATO films were calculated, showing an increase in the bandgap with higher doping levels. These findings were thoroughly analyzed and discussed; additionally, an effort was made to clarify the contradictory analyses present in the literature and to identify a doping range that avoids the onset of a secondary phase. Full article
(This article belongs to the Special Issue Optical–Electric–Magnetic Multifunctional Composite Materials)
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15 pages, 2849 KiB  
Article
Improving the Corrosion Resistance of Titanium by PAA/Chitosan Bilayer Architecture Through the Layer-by-Layer Method
by Daniele Morais Dias, Murilo Oliveira Alves Ferreira, Ana Paula Ramos, Witor Wolf, Jéferson Aparecido Moreto and Rodrigo Galo
Polysaccharides 2025, 6(3), 57; https://doi.org/10.3390/polysaccharides6030057 - 1 Jul 2025
Viewed by 352
Abstract
To enhance interaction with the host tissue and protect the metal surface, various surface treatments can be applied to dental implants. This study aimed to produce layer-by-layer (LbL) films by alternated immersion of the titanium sample into polyacrylic acid (PAA) and chitosan solutions, [...] Read more.
To enhance interaction with the host tissue and protect the metal surface, various surface treatments can be applied to dental implants. This study aimed to produce layer-by-layer (LbL) films by alternated immersion of the titanium sample into polyacrylic acid (PAA) and chitosan solutions, obtaining a PAA/chitosan bilayer architecture, seeking to improve the corrosion resistance. For this purpose, 03 experimental groups (n = 05) were performed: Ti-Cp (as control), Ti-Cp+8 bilayers PAA/chitosan, and Ti-Cp+12 bilayers PAA/chitosan. The corrosion behavior was assessed by using open-circuit potential (OCP), potentiodynamic polarization curves (PPcs) and electrochemical impedance spectroscopy (EIS) techniques, conducted in 0.9 wt% NaCl solution at a controlled temperature of 25 ± 1 °C. The samples were characterized morphologically and structurally by atomic force microscope (AFM), scanning electron microscopy/energy-dispersive X-ray (SEM/EDX), and X-ray diffraction (XRD) techniques before and after the corrosion tests. The electrochemical results significantly highlight the beneficial influence of coatings based on PAA/chitosan in enhancing the corrosion resistance of titanium. These findings not only corroborate the feasibility of using alternative materials for the protection of titanium but also open new possibilities for the development of innovative coatings that can be applied within the biomedical sector, serving as mediators for medicinal purposes, particularly in osteoconductive interventions. Full article
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13 pages, 6820 KiB  
Article
An Exploration of SPS Fabrication and the Sliding Wear Properties of γ-TiAl-Ag Self-Lubrication Materials
by Na Xiao, Chenglong Yang, Shengfei Zhou, Yuliang Yin, Dian Zhao, Yulong Shi and Kang Yang
Surfaces 2025, 8(3), 45; https://doi.org/10.3390/surfaces8030045 - 30 Jun 2025
Viewed by 348
Abstract
To promote the optimization of the anti-friction and anti-wear behavior of lightweight TiAl alloys, γ-TiAl-10 wt.% Ag self-lubricating composites were fabricated, and their mechanical and tribological properties were tested. The results showed that the silver in TiAl-10 wt.% Ag slightly reduced its mechanical [...] Read more.
To promote the optimization of the anti-friction and anti-wear behavior of lightweight TiAl alloys, γ-TiAl-10 wt.% Ag self-lubricating composites were fabricated, and their mechanical and tribological properties were tested. The results showed that the silver in TiAl-10 wt.% Ag slightly reduced its mechanical properties compared with those of pure TiAl alloys. A silver-enriched lubrication film formed on a wear scar, which was helpful in improving the friction and wear behavior. It was found that a large amount of silver gathered at a wear scar, gradually spread out under the action of the sliding friction force, and then increased the silver distribution areas on the wear scar, leading to the good formation of a silver-rich film. Furthermore, an identification model was established to calculate the specific area η of the silver film. A quantitative relationship indicated that an increase in the Ag distribution area improved the tribological behavior of γ-TiAl-10 wt.% Ag. When the specific area η of a silver-rich film was maintained at 44–51%, the small friction coefficient (almost 0.28) and wear rate (about 2.25 × 10−4 mm3·N−1·m−1) were well stabilized. This provides a new research method to improve the tribological performance of TiAl-Ag samples. Full article
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22 pages, 8571 KiB  
Article
Optimization of Micro-Sandblasting Parameters for Enhanced Adhesion and Wear Resistance of AlTiSiN-Coated Tools
by Junlong Wang, Jiaxuan Du, Zhipeng Liu, Hongliang Qian and Qi Wang
Coatings 2025, 15(7), 757; https://doi.org/10.3390/coatings15070757 - 26 Jun 2025
Viewed by 396
Abstract
Micro-sandblasting pretreatment was applied to AlTiSiN-coated WC–Co tools to enhance cutting performance in 316 L stainless steel milling. An L9(33) Taguchi orthogonal array varied passivation pressure (0.1, 0.2, and 0.3 MPa), gun traverse speed (60, 80, and 100 m/min), [...] Read more.
Micro-sandblasting pretreatment was applied to AlTiSiN-coated WC–Co tools to enhance cutting performance in 316 L stainless steel milling. An L9(33) Taguchi orthogonal array varied passivation pressure (0.1, 0.2, and 0.3 MPa), gun traverse speed (60, 80, and 100 m/min), and tool rotation speed (20, 30, and 40 r/min). Coating thickness varied only from 0.93 to 1.19 μm, and surface roughness remained within 0.044–0.077 μm, confirming negligible thickness and roughness effects. Under optimized conditions, coating adhesion strength and nano-hardness both exhibited significant improvements. A weighted-scoring method balancing these two responses identified the optimal pretreatment parameters as 0.1 MPa, 80 m/min, and 20 r/min. Milling tests at 85 m/min—using flank wear VBₘₐₓ = 0.1 mm as the failure criterion—demonstrated a cutting distance increase from 4.25 m (untreated) to 12.75 m (pretreated), a 200% improvement. Wear progressed through three stages: rapid initial wear, extended steady wear due to Al2O3 protective-film formation and Si-induced oxygen-diffusion suppression, and accelerated wear. Micro-sandblasting further prolonged the steady-wear phase by removing residual cobalt binder, exposing WC grains, and offsetting tensile residual stresses. These findings establish a practical, cost-effective micro-sandblasting pretreatment strategy that significantly enhances coating adhesion, hardness, and tool life, providing actionable guidance for improving the durability and machining performance of coated carbide tools in difficult-to-cut applications. Full article
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