Artykuły w czasopismach na temat „Nitrure de titane (TiN)”
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1
Kabbaj, M., A. Galerie i M. Caillet. "Revêtements composites TiAl3TiN sur le titane". Journal of the Less Common Metals 108, nr 1 (czerwiec 1985): 1–21. http://dx.doi.org/10.1016/0022-5088(85)90427-8.
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Nardou, F., P. Raynaud i M. Billy. "Role de l'hydrogene dans le comportement du nitrure de titane en presence de melanges H2-H2O". Journal of the Less Common Metals 144, nr 2 (grudzień 1988): 321–29. http://dx.doi.org/10.1016/0022-5088(88)90146-4.
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Oh, Han Jun. "Synthesis of N Doped Titania Photocatalyst by Using an Electrochemical Oxidation of TiN Layer". Advanced Materials Research 651 (styczeń 2013): 302–5. http://dx.doi.org/10.4028/www.scientific.net/amr.651.302.
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In order to improve the photocatalytic efficiency, the N doped anodic titania film for photocatalyst was synthesized by anodic oxidation of TiN layer in sulfuric electrolyte, and the photocatalytic properties of N doped TiO2layer were investigated. During the oxidation process of the TiN layer, nitrogen was doped into the anodic titania film due to the change of the titanium nitride layer to TiO2layer film. In the evaluation of dye degradation, N doped titania catalyst shows much higher efficiency than non-doped titania film.
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Pacheco, F., R. Palomino, G. Martínez, A. Mendoza-Galván, R. Rodriguez i V. M. Castaño. "Optical Properties of Titania-Cobalt Nitrate Composite Thin Films". Advanced Composites Letters 5, nr 6 (listopad 1996): 096369359600500. http://dx.doi.org/10.1177/096369359600500603.
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Optical properties of titania thin films supported on silica plates and compounded with varying amounts of Co(II) from cobalt nitrate are reported. The ellipsometric characterization allows to model the spatial micro-structure of these thin film composites. The titania films were produced by the sol-gel method at room temperature and their thicknesses can be controlled by modifying the experimental conditions. The refractive index of the doped titania films was also determined by using ellipsometry.
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Choi, Jong-Jin, Gun-Tae Park, Chee-Sung Park i Hyoun-Ee Kim. "Ferroelectric and piezoelectric properties of highly oriented Pb(Zr,Ti)O3 film grown on Pt/Ti/SiO2/Si substrate using conductive lanthanum nickel nitrate buffer layer". Journal of Materials Research 20, nr 3 (1.03.2005): 726–33. http://dx.doi.org/10.1557/jmr.2005.0087.
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The orientation and electrical properties of Pb(Zr,Ti)O3 thin films deposited on a Pt/Ti/SiO2/Si substrate using lanthanum nickel nitrate as a conductive buffer layer were analyzed. The lanthanum nickel nitrate buffer layer was not only electrically conductive but also effective in controlling the texture of the lead zirconate titanate (PZT) thin film. The role of the lanthanum nickel nitrate buffer layer and its effects on the orientation of the PZT thin film were analyzed by x-ray diffraction, electron beam back-scattered diffraction, and scanning electron microscopy. The annealed lanthanum nickel nitrate buffer layer was sufficiently conducting for use in longitudinal electrode configuration devices. The dielectric, ferroelectric, and piezoelectric properties of the highly (100) oriented PZT films grown with the lanthanum nickel nitrate buffer layer were measured and compared with those of (111) and (100) oriented PZT films deposited without a buffer layer.
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Ben Aissa, Chokri, i Kaouther Khlifi. "Caractérisation nano-mécanique et tribologique des revêtements TiO2 et TiN déposés sur acier inoxydable 316L pour applications biomédicales". Matériaux & Techniques 109, nr 1 (2021): 104. http://dx.doi.org/10.1051/mattech/2021016.
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Dans ce travail, nous avons développé des couches nanométriques biocompatibles à base de titane (TiN et TiO2) sur acier inoxydable 316L, par CAE-PVD (Cathodic Arc Evaporation), qui est un procédé efficace pour la synthèse de revêtements de haute qualité. Nous avons axé notre étude sur une caractérisation mécanique et tribologique des revêtements par des tests d’indentation et des rayures. Les résultats obtenus montrent une morphologie dense et uniforme couplée à des propriétés mécaniques et interfaciales importantes. Les revêtements TiN et TiO2 ont montré une dureté comprise entre 5,9 GPa et 8,23 GPa. La mesure de l’adhérence par des tests de rayure a montré que les deux revêtements ont une qualité d’adhérence légèrement différente. Les couches développées en TiN et TiO2 ont montré des charges de cohésion critiques comprises entre 1,8 N et 3,3 N avec une charge d’adhérence critique de 13,1 N. Les propriétés tribologiques ont été étudiées, en utilisant un test de Scratch multi-passes à charge constante, ce qui a permis de déterminer le coefficient de frottement et le taux d’usure énergétique. Les coefficients de frottement des deux couches étudiées sont du même ordre de grandeur (0,1), mais on peut dire que la résistance au frottement varie d’une couche à l’autre. L’énergie spécifique d’usure était comprise entre 3,09 × 10−5 J/μm3 et 8,36 × 10−5 J/μm3, et elle n’a pas changé après immersion de la couche de TiN pendant 48 h dans une solution de NaCl à 3 %. Le film mince de TiN, connu pour sa biocompatibilité et ses performances biologiques, a montré des propriétés mécaniques et tribologiques qui lui permettent d’être utilisé dans les implants de hanche et de genou.
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Falaras, P., I. M. Arabatzis, T. Stergiopoulos i M. C. Bernard. "Enhanced activity of silver modified thin-filmTiO2photocatalysts". International Journal of Photoenergy 5, nr 3 (2003): 123–30. http://dx.doi.org/10.1155/s1110662x03000230.
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Novel, composite silver/titania immobilized on glass substrates were prepared, characterized and their photocatalytic activity was evaluated. The undoped original material consists of rough, high surface area nanocrystalline titanium dioxide (TiO2) thin films. To increase their efficiency, the TiO2films were modified by silver cations deposition and subsequent UV-C irradiation. SEM pictures confirmed the existence of an open porous network of interconnected titania particles on the semiconductor surface. AFM analysis proved the presence of spherical silver particles on the catalyst surface and provided quantitative surface parameters as fractal dimension, surface roughness and mean particle diameter. Spectroreflectometry showed the presence of an increase in optical absorbance attributed to plasmon resonance absorption of the silver clusters. The photocatalytic properties of the surface modified materials were investigated through photodegradation of Methyl Orange. The silver deposition conditions were optimized for maximum photocatalytic efficiency and crucial parameters such as dipping period, UV irradiation time, and concentration of the dipping solution were determined. The optimum silver nitrate concentration of the dipping solution was found to be10-3M. This silver doped photocatalyst decomposes the azo-dye pollutant 3-times faster than the un-doped Degussa P25TiO2film. A concentration increase results in a decrease of the films photocatalytic performance. Strength and reproducibility tests proved that the photocatalytic activity of the silver doped titania was perfectly reproducible.
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Lisińska-Czekaj, Agata, M. Czaja, Lucjan Kozielski, Dionizy Czekaj, M. Piechowiak, M. Nowakowski i K. Zawiślok. "Photoluminescence of Nanocrystalline Bismuth Titanate Thin Films Synthesized by the Sol-Gel Method". Materials Science Forum 514-516 (maj 2006): 128–32. http://dx.doi.org/10.4028/www.scientific.net/msf.514-516.128.
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The present study is devoted to synthesis and investigation of photoluminescence in the nanosized Bi4Ti3O12 (BTO) thin films. The randomly oriented BTO thin films have been obtained by a modified hybrid sol-gel process. Bismuth nitrate and titanium (IV) butoxide were used as the starting materials. The thin films were deposited on silicon, glass and stainless steel by spin coating and crystallized by the conventional thermal annealing at temperature T=650°C. Formation of the layer perovskite-type structure of the orthorhombic symmetry was confirmed by X-ray diffraction method. Conservation of the chemical composition was investigated by energy dispersive spectroscopy. The UV luminescence has been observed in BTO thin films at room temperature. Results on luminescence excitation and emission in bismuth titanate thin films are given in the present paper.
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Žener, Boštjan, Lev Matoh, Giorgio Carraro, Bojan Miljević i Romana Cerc Korošec. "Sulfur-, nitrogen- and platinum-doped titania thin films with high catalytic efficiency under visible-light illumination". Beilstein Journal of Nanotechnology 9 (4.06.2018): 1629–40. http://dx.doi.org/10.3762/bjnano.9.155.
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Titanium dioxide photocatalysts have received a lot of attention during the past decades due to their ability to degrade various organic pollutants to CO2 and H2O, which makes them suitable for use in environmental related fields such as air and water treatment and self-cleaning surfaces. In this work, titania thin films and powders were prepared by a particulate sol–gel route, using titanium tetrachloride (TiCl4) as a precursor. Afterwards, the prepared sols were doped with nitrogen (ammonium nitrate, urea), sulfur (thiourea) and platinum (chloroplatinic acid), coated onto glass substrates by dip-coating, and thermally treated in a muffle furnace to promote crystallization. The resulting thin films were then characterized by various techniques (i.e., TGA-DSC-MS, XRD, BET, XPS, SEM, band gap measurements). The photocatalytic activity of the prepared thin films was determined by measuring the degradation rate of plasmocorinth B (PB), an organic pigment used in the textile industry, which can pose an environmental risk when expelled into wastewater. A kinetic model for adsorption and subsequent degradation was used to fit the experimental data. The results have shown an increase in photocatalytic activity under visible-light illumination of nonmetal and metal doped and co-doped titania thin films compared to an undoped sample.
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Schmitz, Tobias, Maren Jannasch, Tobias Weigel, Claus Moseke, Uwe Gbureck, Jürgen Groll, Heike Walles i Jan Hansmann. "Nanotopographical Coatings Induce an Early Phenotype-Specific Response of Primary Material-Resident M1 and M2 Macrophages". Materials 13, nr 5 (4.03.2020): 1142. http://dx.doi.org/10.3390/ma13051142.
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Implants elicit an immunological response after implantation that results in the worst case in a complete implant rejection. This biomaterial-induced inflammation is modulated by macrophages and can be influenced by nanotopographical surface structures such as titania nanotubes or fractal titanium nitride (TiN) surfaces. However, their specific impact on a distinct macrophage phenotype has not been identified. By using two different levels of nanostructures and smooth samples as controls, the influence of tubular TiO2 and fractal TiN nanostructures on primary human macrophages with M1 or M2-phenotype was investigated. Therefore, nanotopographical coatings were either, directly generated by physical vapor deposition (PVD) or by electrochemical anodization of titanium PVD coatings. The cellular response of macrophages was quantitatively assessed to demonstrate a difference in biocompatibility of nanotubes in respect to human M1 and M2-macrophages. Depending on the tube diameter of the nanotubular surfaces, low cell numbers and impaired cellular activity, was detected for M2-macrophages, whereas the impact of nanotubes on M1-polarized macrophages was negligible. Importantly, we could confirm this phenotypic response on the fractal TiN surfaces. The results indicate that the investigated topographies specifically impact the macrophage M2-subtype that modulates the formation of the fibrotic capsule and the long-term response to an implant.
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Sakka, Yoshio, Tohru Suzuki i Tetsuo Uchikoshi. "Fabrication and Some Properties of Textured Ceramics by Colloidal Processing in High Magnetic Field". Key Engineering Materials 352 (sierpień 2007): 101–6. http://dx.doi.org/10.4028/www.scientific.net/kem.352.101.
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Recently to improve properties, highly microstructure controlled ceramics such as fine-grained, textured and laminated structures are required. We have demonstrated a new processing of textured ceramics with a feeble magnetic susceptibility by colloidal processing in a high magnetic field and subsequent heating. As colloidal processing, slip casting and electrophoretic deposition (EPD) have been conducted successfully. Colloidal processing is known to be a powerful method for consolidating fine particles with a high density and homogeneous microstructure. The degree of orientation strongly depends on the particle dispersion and some processing factors, such as particle size, applied magnetic field, concentration of the suspension, sintering temperature, etc. Crystalline-textured controlled laminated composites can be fabricated using EPD by varying the angle between the vectors of electric field and magnetic field. Also textured ceramics with complicated structure can be fabricated by reaction sintering. The colloidal processing in a high magnetic field confers several advantages and it is possible for this type of processing to be applied to non-cubic ceramics, such as alumina, titania, zinc oxide, tin oxide, hydroxy apatite, aluminium nitride, silicon carbide, silicon nitride, etc. The textured ceramics showed anisotropic properties depending on the crystal plane.
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Zhang, Jing, Zhengxing Huang, Liming Zheng, Xiaobo Tian, Wengang Yin i Shihua Ding. "Research on Photo Catalytic Performance of TiO2 Film Doped with Li+". MATEC Web of Conferences 358 (2022): 01047. http://dx.doi.org/10.1051/matecconf/202235801047.
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Based on sol-gel method and spin coating process, TiO2 film doped with Li+ is prepared by utilizing analytical pure butyl titanate, lithium nitrate, absolute ethanol, glacial acetic acid, acetylacetone and deionized water as raw material. The Li+ ion which has equal radius as Ti4+ ion is chosen in experiments for doping and modification. Experimental results show certain increase of catalytic efficiency in TiO film doped with Li+. However, the increase level of catalytic efficiency gradually shows some decrease when the dopant amount changes from 0.025mol to 0.1mol. Catalytic efficiency is raised to 25.7% when the dopant amount is 0.025mol.
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Ma, Youcao, Jian Song, Xubo Wang, Yue Liu i Jia Zhou. "Synthesis, Microstructure and Properties of Magnetron Sputtered Lead Zirconate Titanate (PZT) Thin Film Coatings". Coatings 11, nr 8 (7.08.2021): 944. http://dx.doi.org/10.3390/coatings11080944.
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Compared to aluminum nitride (AlN) with simple stoichiometry, lead zirconate titanate thin films (PZT) are the other promising candidate in advanced micro-electro-mechanical system (MEMS) devices due to their excellent piezoelectric and dielectric properties. The fabrication of PZT thin films with a large area is challenging but in urgent demand. Therefore, it is necessary to establish the relationships between synthesis parameters and specific properties. Compared to sol-gel and pulsed laser deposition techniques, this review highlights a magnetron sputtering technique owing to its high feasibility and controllability. In this review, we survey the microstructural characteristics of PZT thin films, as well as synthesis parameters (such as substrate, deposition temperature, gas atmosphere, and annealing temperature, etc.) and functional proper-ties (such as dielectric, piezoelectric, and ferroelectric, etc). The dependence of these influential factors is particularly emphasized in this review, which could provide experimental guidance for researchers to acquire PZT thin films with expected properties by a magnetron sputtering technique.
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Kim, Hyunho, Adrees Arbab, Benji Fenech-Salerno, Chengning Yao, Ryan Macpherson, Jong Min Kim i Felice Torrisi. "Barium titanate-enhanced hexagonal boron nitride inks for printable high-performance dielectrics". Nanotechnology 33, nr 21 (4.03.2022): 215704. http://dx.doi.org/10.1088/1361-6528/ac553f.
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Abstract Printed electronics have been attracting significant interest for their potential to enable flexible and wearable electronic applications. Together with printable semiconductors, solution-processed dielectric inks are key in enabling low-power and high-performance printed electronics. In the quest for suitable dielectrics inks, two-dimensional materials such as hexagonal boron nitride (h-BN) have emerged in the form of printable dielectrics. In this work, we report barium titanate (BaTiO3) nanoparticles as an effective additive for inkjet-printable h-BN inks. The resulting inkjet printed BaTiO3/h-BN thin films reach a dielectric constant (ε r) of ∼16 by adding 10% of BaTiO3 nanoparticles (in their volume fraction to the exfoliated h-BN flakes) in water-based inks. This result enabled all-inkjet printed flexible capacitors with C ∼ 10.39 nF cm−2, paving the way to future low power, printed and flexible electronics.
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Wang, S. X., L. M. Wang i C. L. Lin. "XTEM Study of the Microstructure of PZT Thin Films". Microscopy and Microanalysis 6, S2 (sierpień 2000): 458–59. http://dx.doi.org/10.1017/s1431927600034784.
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Lead zirconate titanate (PbZrxTil-xO3, PZT) is one of the important ferroelectric materials for the storage elements of high-speed non-volatile memories. It also has much potential to be used in pyroelectric sensor, ultrasonic motor, and multiplayer ceramic capacitor.PZT (Zr/Ti = 48/52) thin films were prepared using a metal-organic decomposition (MOD) process. The precursor solution used for PZT thin film preparation was based on lead acetate trihydrate, Pb(CH3COO)2; zirconium nitrate, Zr(NO3)4.5H2O; and titanium nbutoxide, Ti(nC2H9)4. 2-butoxyethanol was chosen as a solvent. A 30% excess Pb was added to the precursor to compensate for the loss of lead oxide during the annealing process. Acetic acid was used as a complexing agent for PZT solution to control the hydrolysis and condensation rates. The 0.3M precursor solution was spin-coated on the Pt(111)/Ti/SiO2/Si substrates for 20s at 3000 rpm. The deposited film was fired at 450 °C for 10 min and repeated five times to burn out the organics. The films were crystallized at 600 °C in air for 1 hr.
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Cabello-Ribota, Blanca Selenis, Rurik Farías i Simón Yobanny Reyes-López. "Surface Enhanced Infrared Absorption Studies of SiO2–TiO2–Ag Nanofibers: Effect of Silver Electrodeposition Time on the Amplification of Signals". Crystals 11, nr 5 (19.05.2021): 563. http://dx.doi.org/10.3390/cryst11050563.
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Surface Enhanced on Infrared Absorption (SEIRAS) and Raman Spectroscopy (SERS) are nondestructive analytic techniques used to detect low concentrations and recognize the fingerprints of molecules. The recognition of the absorption from samples by conventional infrared spectroscopy (IR) via Attenuated Total Reflection (ATR) is difficult for molecules with a low signal strength. However, developed structures with SERS and SEIRAS effect present problems such as high cost, low stability, and low compatibility. Research into new media to obtain greater amplification is largely based on the creation of nanoscale structures with symmetrical arrangements and reproducible distances, resulting in aggregates of nanoparticles that help generate hot spots which are active for amplification. The sol-gel and electrospinning method for the obtention of ceramics provides an alternative means by which to produce said substrates. Fibers of nanometric scale provide an increase of surface area which allows more contact to occur with analytes. Consequently, in this study, a silica-titania-silver nanostructured support that amplifies signal intensity for Raman and infrared spectroscopy was developed. The silica-titania support was developed by sol-gel and electrospinning techniques, and the as spun fibers were treated at 800 °C. Then, the ceramic fibrous membrane was placed on conductive indium tin oxide plastic to be doped with silver using an electroplating technique, varying the silver nitrate concentration (5, 10 and 20 mM), as well as electrodeposition times (1, 2, 5 and 10 min), with a constant voltage (1 V). Twelve different supports were obtained that showed amplification. The enhancement of infrared signals from pyridine and crystal violet molecules adsorbed on silica-titania-silver (SiO2–TiO2–Ag) nanofibers was studied in situ by Attenuated Total Reflection-Fourier Transformed Infrared Spectroscopy (ATR-FTIR). The highest amplification was obtained by the support doped at 10 min in a 10 mM concentration, with an amplification factor of 2.74 in the band localized at 3301 cm−1. In Raman spectroscopy, the highest amplification factor was 27.03, on the support doped for 5 min at a concentration of 5 mM.
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Chen, Hua Jun, Xiao Jing Xi, Dong Li i Rui Wang. "Preparation and Photocatalytic Activity of Bi Doped TiO2 with Visible-Light Response". Advanced Materials Research 550-553 (lipiec 2012): 404–10. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.404.
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A Bi-TiO2 composite with high photocatalytic activity was prepared using tetrabutyl titanate and bismuth nitrate as raw material by hydrothermal method. The structure was characterized by X-ray diffraction(XRD), transmission electron microscopy(TEM), X-ray energy dispersive spectroscopy(EDS), X-ray fluorescence(XRF) and UV-vis diffuse reflectance spectrophotometer(UV-vis DRS). The results show that anatase nanometer titanium dioxide was prepared, in which Bi3+ take the place of Ti4+. The surface area of the sample was higher, ca.312.6m2•g-1. Bi doping caused red-shift of the absorption spectrum, and the composite has better Visible-light Response. Bi-TiO2 shows higher photocatalytic avtivity to the degradation of resorcinol than pure TiO2. The optimum value of Bi doped was 1.00 %. After 120 minutes illuminating under 70W Halide Lamps, degradation rate of resorcinol can get to 100%.
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Zhou, Junchao, Mingzhao Liu, Ming Lu i Pao Tai Lin. "Mid-infrared frequency doubling using strip-loaded silicon nitride on epitaxial barium titanate thin film waveguides". Optics Letters 45, nr 23 (19.11.2020): 6358. http://dx.doi.org/10.1364/ol.403760.
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Tryba, Beata, Bartłomiej Prowans, Rafał Jan Wróbel, Paulina Szołdra i Waldemar Pichór. "Application of TiO2 Supported on Nickel Foam for Limitation of NOx in the Air via Photocatalytic Processes". Molecules 29, nr 8 (12.04.2024): 1766. http://dx.doi.org/10.3390/molecules29081766.
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TiO2 was loaded on the porous nickel foam from the suspended ethanol solution and used for the photocatalytic removal of NOx. Such prepared material was heat-treated at various temperatures (400–600 °C) to increase the adhesion of TiO2 with the support. Obtained TiO2/nickel foam samples were characterized by XRD, UV–Vis/DR, FTIR, XPS, AFM, SEM, and nitrogen adsorption at 77 K. Photocatalytic tests of NO abatement were performed in the rectangular shape quartz reactor, irradiated from the top by UV LED light with an intensity of 10 W/m2. For these studies, a laminar flow of NO in the air (1 ppm) was applied under a relative humidity of 50% and a temperature of 28 °C. Concentrations of both NO and NO2 were monitored by a chemiluminescence NO analyzer. The adsorption of nitrogen species on the TiO2 surface was determined by FTIR spectroscopy. Performed studies revealed that increased temperature of heat treatment improves adhesion of TiO2 to the nickel foam substrate, decreases surface porosity, and causes removal of hydroxyl and alcohol groups from the titania surface. The less hydroxylated surface of TiO2 is more vulnerable to the adsorption of NO2 species, whereas the presence of OH groups on TiO2 enhances the adsorption of nitrate ions. Adsorbed nitrate species upon UV irradiation and moisture undergo photolysis to NO2. As a consequence, NO2 is released into the atmosphere, and the efficiency of NOx removal is decreasing. Photocatalytic conversion of NO to NO2 was higher for the sample heated at 400 °C than for that at 600 °C, although coverage of nickel foam by TiO2 was lower for the former one. It is stated that the presence of titania defects (Ti3+) at low temperatures of its heating enhances the adsorption of hydroxyl groups and the formation of hydroxyl radicals, which take part in NO oxidation. Contrary to that, the presence of titania defects in TiO2 through the formation of ilmenite structure (NiTiO3) in TiO2/nickel foam heated at 600 °C inhibits its photocatalytic activity. No less, the sample obtained at 600 °C indicated the highest abatement of NOx due to the high and stable adsorption of NO2 species on its surface.
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Du, Huiling, Cuiying Ma, Wuxiang Ma i Haiting Wang. "Microstructure evolution and dielectric properties of Ce-doped SrBi4Ti4O15 ceramics synthesized via glycine-nitrate process". Processing and Application of Ceramics 12, nr 4 (2018): 303–12. http://dx.doi.org/10.2298/pac1804303d.
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Ce-doped strontium bismuth titanate (SrBi4Ti4O15, SBT) powders were prepared by glycine-nitrate process at 400-500?C and the ceramics were sintered at 980?C. The phase composition, morphology and electric properties were investigated. It was found that the calcined powders consist of a single phase SBT and the calcination temperature is lower than that for the conventional solid state method. The morphology of Cedoped SBT is flake-like and the layer size decreases with Ce-addition from 12 to 2?m confirming that the addition of Ce3+ inhibits grain growth. The Curie temperature of Ce-doped SBT increased for about 20?C compared to the pure SBT. The tan ? was ~0.005 at 35?C and even below 0.05 up to 400?C. The temperature coefficient of dielectric constant was ~0.012 and the rate of frequency change was 0.01-0.04, which indicated the high stability of dielectric properties of the Ce-doped SBT. Impedance analysis revealed that the conduction mechanism of the Ce-doped SrBi4Ti4O15 ceramics is mainly grain conduction.
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Junmin, Xue, i John Wang. "Lead Zirconate Titanate Via Reaction Sintering of Hydroxide Precursors". Journal of Materials Research 14, nr 4 (kwiecień 1999): 1503–9. http://dx.doi.org/10.1557/jmr.1999.0201.
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Lead zirconate titanate (PZT) has been successfully fabricated via a unique one-step sintering processing route, which is simpler than the traditional precursor-calcinationmilling- pelleting-sintering route and is able to deliver an enhanced sintered density at a much reduced sintering temperature. The hydroxide precursor was prepared by coprecipitation from a mixed nitrate solution containing Pb2+, Zr4+, and Ti4+ ions, and it was then compacted into pellets without being calcined at a low temperature. The precursor pellets were dehydrated at 400, 500, and 600 °C for 4 h, respectively, followed by an isostatic pressing at 350 MPa, prior to being sintered at a high temperature. Dehydration temperature has a large impact on the sintering behavior of these hydroxide-derived PZT ceramics. The PZT dehydrated at 400 °C was seriously cracked when sintered at temperatures ranging from 950 to 1150 °C, due to the incomplete dehydration. A sintered density of 99.2% theoretical density was obtained at 1050 °C for 2 h for the powder pellet dehydrated at 500 °C for 4 h. It exhibits a dielectric constant of 1024 and a dielectric loss of 2.1% at a frequency of 1 kHz at room temperature. A calcination at a too-high temperature, e.g., 600 °C, results in a reduction in the sinterability of the precipitate-derived PZT ceramic.
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Chipatecua Godoy, Yuri, Olof Tengstrand, Jairo Olaya Florez, Ivan Petrov, Erika Bustos, Lars Hultman, Alberto Herrera-Gomez, J. E. Greene i Grzegorz Greczynski. "Corrosion Resistant TiTaN and TiTaAlN Thin Films Grown by Hybrid HiPIMS/DCMS Using Synchronized Pulsed Substrate Bias with No External Substrate Heating". Coatings 9, nr 12 (9.12.2019): 841. http://dx.doi.org/10.3390/coatings9120841.
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Ti0.92Ta0.08N and Ti0.41Al0.51Ta0.08N thin films grown on stainless-steel substrates, with no external heating, by hybrid high-power impulse and dc magnetron sputtering (HiPIMS/DCMS), were investigated for corrosion resistance. The Ta target was operated in HiPIMS mode to supply pulsed Ta-ion fluxes, while two Ti (or Ti and Al) targets were operated in DCSM mode in order to provide a high deposition rate. Corrosion resistance was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy employing a 3.5% NaCl solution at room temperature. The 300-nm-thick transition-metal nitride coatings exhibited good corrosion resistance due to film densification resulting from pulsed heavy Ta-ion irradiation during film growth. Corrosion protective efficiencies were above 99.8% for both Ti0.41Al0.51Ta0.08N and Ti0.92Ta0.08N, and pore resistance was apparently four orders of magnitude higher than for bare 304 stainless-steel substrates.
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Yao, Lan Fang, Xiong Tang, Xin Pei Yan i Lin Li. "Preparation and Photocatalytic Activity of Nd3+and CTAB Co-Doped Nanometer TiO2 Thin Films". Key Engineering Materials 562-565 (lipiec 2013): 858–63. http://dx.doi.org/10.4028/www.scientific.net/kem.562-565.858.
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Pure TiO2, Nd3+doped TiO2 and Nd 3+-CTAB co-doped TiO2 nanometer thin films were prepared by the sol-gel technique with tetrabutyl titanate and neodymium nitrate as raw materials and surfactant cetyltrimethylammonium bromide (CTAB) as template. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Visible absorbance spectroscopy (UV-Vis). The photocatalytic activity was evaluated by photocatalytic degradation of methyl orange. The results show that the all samples calcined at 500°C are all anatase, and there are slight red shifts of the Nd3+doped TiO2 and Nd3+-CTAB co-doped TiO2 films compared with pure TiO2 films and the red shift of Nd 3+-CTAB co-doped TiO2 is more obvious than that of Nd 3+ doped TiO2, which is beneficial to improve the photocatalytic efficiency. The1.0% Nd3+-CTAB co-doped TiO2 nanometer film calcined at 500°C had excellent photocatalytic efficiencies and the degradation rate of the film is more than 90% after 120 min.
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Ongmali, Duangamol, Sakollapath Pithakratanayothin, Sureerat Jampa, Apanee Luengnaruemitrchai, Thanyalak Chaisuwan i Sujitra Wongkasemjit. "Remarkable Activity of Nanoarchitectonics Mesoporous CuO/CeO2–TiO2 Prepared by Nanocasting and Deposition Precipitation Techniques". Journal of Nanoscience and Nanotechnology 20, nr 5 (1.05.2020): 2791–802. http://dx.doi.org/10.1166/jnn.2020.17428.
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In this work, a ceria (CeO2) support was modified with titania (TiO2) by nanocasting using MCM-48 as a hard template and then loading Cu (as the nitrate salt) at different levels (3–9% by weight) by deposition-precipitation followed by calcination. The addition of TiO2 in MSP CeO2 revealed that the MSP CeO2 was significantly improved the oxygen vacancies of the catalyst by increasing the Ce3+ content from 38 to 75% and stabilizing the Ce3+ species by bonding with the oxygen as Ce(4f)-O(2p)-Ti(3d). Moreover, the bonding of MSP CeO2 with TiO2 generated the oxygen defect vacancies (s–Ti3+), allowing Cu2+ to occupy and be reduced to Cu+ during calcination. The smaller CeO2 crystallite size (2.7 nm) of 9Cu/CeO2–TiO2 increased the mass-specific CO-Oxidation, showing the best catalytic activity due to its highest redox properties, as determined by H2-TPR and also showing resistant property to water and carbon dioxide. Indeed, water was adsorbed on the Ce3+ sites, generating OHads which reacted with CO to form –COOH, resulting in CO2.
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Park, S. J., i J. G. Eden. "Electrical characteristics and lifetimes of microdischarge devices having thin dielectric films of aluminum oxide,boron nitride, or barium titanate". Electronics Letters 39, nr 10 (2003): 773. http://dx.doi.org/10.1049/el:20030430.
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Vargas, S., R. Arroyo, E. Haro i R. Rodríguez. "Effects of cationic dopants on the phase transition temperature of titania prepared by the sol-gel method". Journal of Materials Research 14, nr 10 (październik 1999): 3932–37. http://dx.doi.org/10.1557/jmr.1999.0532.
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The effect of different cations in the anatase–rutile phase transition temperatures for titania prepared by the sol-gel method was studied. The metal dopants were chosen from different periods and groups of the periodic table to see the role played by the electronic configuration, the oxidizing state, the atomic size, etc. on these temperature modifications. Linear relationships between the anatase–rutile phase transition temperatures and the ionic radii for alkali metal, alkaline earth metal, and group 3 and 13 elements were obtained. For elements of the period 4, there was not such a defined tendency; for most of them the modification of the phase transition temperature was too small. The cations used were Li+, Na+, K+, Mg2+, Ca2+, Sr2+, Ba2+, Al3+, Y3+, La3+, Er3+, Ti4+, Co2+, Ni2+, Cu2+, and Zn2+. In all cases the dopant's concentration was 2 mol% with respect to titanium, and the same anion (nitrate) was used for all salts. A variation of more than 330 °C in the anatase–rutile phase transition temperatures was obtained by using these dopants. The transition temperatures from amorphous to anatase and from anatase to rutile phases were obtained from the x-ray diffractograms.
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Kazys, Rymantas, i Vaida Vaskeliene. "High Temperature Ultrasonic Transducers: A Review". Sensors 21, nr 9 (5.05.2021): 3200. http://dx.doi.org/10.3390/s21093200.
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There are many fields such as online monitoring of manufacturing processes, non-destructive testing in nuclear plants, or corrosion rate monitoring techniques of steel pipes in which measurements must be performed at elevated temperatures. For that high temperature ultrasonic transducers are necessary. In the presented paper, a literature review on the main types of such transducers, piezoelectric materials, backings, and the bonding techniques of transducers elements suitable for high temperatures, is presented. In this review, the main focus is on ultrasonic transducers with piezoelectric elements suitable for operation at temperatures higher than of the most commercially available transducers, i.e., 150 °C. The main types of the ultrasonic transducers that are discussed are the transducers with thin protectors, which may serve as matching layers, transducers with high temperature delay lines, wedges, and waveguide type transducers. The piezoelectric materials suitable for high temperature applications such as aluminum nitride, lithium niobate, gallium orthophosphate, bismuth titanate, oxyborate crystals, lead metaniobate, and other piezoceramics are analyzed. Bonding techniques used for joining of the transducer elements such as joining with glue, soldering, brazing, dry contact, and diffusion bonding are discussed. Special attention is paid to efficient diffusion and thermo-sonic diffusion bonding techniques. Various types of backings necessary for improving a bandwidth and to obtain a short pulse response are described.
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Zohni, Omar, Gregory Buckner, Taeyun Kim, Angus Kingon, Jeff Maranchi i Richard Siergiej. "Effects of adhesion layers on the ferroelectric properties of lead zirconium titanate thin films deposited on silicon nitride coated silicon substrates". Thin Solid Films 516, nr 18 (lipiec 2008): 6052–57. http://dx.doi.org/10.1016/j.tsf.2007.10.130.
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Kisch, Horst. "In the Light and in the Dark: Photocatalytic Fixation of Nitrogen into Ammonia and Nitrate at Iron Titanate Semiconductor Thin Films". European Journal of Inorganic Chemistry 2020, nr 15-16 (3.01.2020): 1376–82. http://dx.doi.org/10.1002/ejic.201901099.
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Snyder, Mark Q., Svetlana A. Trebukhova, Boris Ravdel, M. Clayton Wheeler, Joseph DiCarlo, Carl P. Tripp i William J. DeSisto. "Synthesis and characterization of atomic layer deposited titanium nitride thin films on lithium titanate spinel powder as a lithium-ion battery anode". Journal of Power Sources 165, nr 1 (luty 2007): 379–85. http://dx.doi.org/10.1016/j.jpowsour.2006.12.015.
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Zhao, Shuai, Dong-Xue Lin i Yu-Xin Wang. "The Synthesis and Optical Properties of Zinc-Nitrogen Co-Doped TiO2 Thin Films Using Sol–Gel Derived Spin-Coating Method". Journal of Nanoelectronics and Optoelectronics 16, nr 6 (1.06.2021): 967–73. http://dx.doi.org/10.1166/jno.2021.3050.
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All of the TiO2 films including intrinsic TiO2 film, Zn single doped film with 2.0 at% content and N doped films with 4.0 at%, 6.0 at%, 8.0 at% and 10.0 at% content, were obtained by butyl titanate (Ti(OC4H9)4) as a titanium source, zinc nitrate (Zn(NO3)2·6H2O) as zinc source and urea (H2 NCONH2) as nitrogen source, which was calcined at 600 °C on the glass substrate and Si substrate using sol–gel spin coating method. The structures, morphology and optical properties of various films were analyzed and studied by X ray diffract meter (XRD), ultraviolet-visible spectrophotometer (UV-Vis) and scanning electron microscope (SEM). The results indicated that the main crystal plane of TiO2 film was (101) and any impurity crystal plane didn't appear. All samples had obvious red shifts in the absorbing edge overall and reduced significantly the width of forbidden band, especially, the N doping content with 8.0 at% was surprised to investigate the strongest (101) peak intensity, the sharpest peak type, the best meritocratic orientation, the greatest red shift of the absorption spectrum, the lowest optical band gap value of 3.356 eV, and the highest utilization rate of visible light of the sample. However, the surface morphology of the others films except the N doping content with 8.0 at% is not further improved by co-doping, that is, their surfaces were still rough, had obvious voids and uneven distribution between the grains. Meanwhile, the intensity of the (101) crystalline diffraction peaks of these samples were reduced and the crystalline spacing generally increased after co-doping.
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Ferdinand, Yao Diby, Assale Fori Jean Paul, Alla Amani Jonas i Digbehi Zeli Bruno. "Caracterisasion Geochimique des Deblais du Substratum de la Baie du Banco, Abidjan, Basse Cote d‘Ivoire". European Scientific Journal, ESJ 19, nr 36 (31.12.2023): 124. http://dx.doi.org/10.19044/esj.2023.v19n36p124.
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L’étude géochimique réalisée s’est éffectuée sur les déblais du substratum de la baie du Banco situé au Sud-est du bassin sédimentaire côtier de la Côte d’Ivoire. Cette étude vise à caractériser le substratum de la baie du Banco à partir des éléments chimiques ainsi que la détermination des paléoconditions des environnements de dépôt. La spectrométrie par fluorescence à rayon x (XRF) a permis de déterminer les éléments majeurs ainsi que des éléments traces présents dans les lutites noirâtres du substratum de la baie. Les éléments majeurs identifiés sont par ordre décroissant le Silicium (45,33 %), le Fer (35,56 %), l’Aluminium (9,24 %), le Potassium (2,31 %), le Calcium (2,22 %), le Titane (2 ,15 %), le Chlore (2,04 %) et le Phosphore (1,12 %). L’analyse géostatistique a permis de mettre en évidence de fortes corrélations entre la matière organique et le fer réduit (Fe 2+), l’étain (Sn), l’arsenic (As) et le soufre (S). Le substratum de la baie du Banco est caractérisé par une forte concentration en soufre variant de 12475 à 75752 ppm et une bioproductivité primaire plus importante en profondeur qu’en surface. Les éléments traces U, V et Mo ont permis d’identifier un milieu euxinique à interface eau-sédiment en subsurface du substratum (0- 32 m) tandis qu’en fin de forage (78-80 m), on distingue un milieu suboxique à anoxique. Ces différents résultats ont permis de caractériser le substratum de la baie du Banco.
The geochemical study was carried out on cuttings from the Banco Bay bedrock in the southeastern part of the Côte d'Ivoire coastal sedimentary basin. The study aimed to characterize the Banco Bay bedrock based on chemical elements and to determine the paleo conditions of the depositional environments. X-ray fluorescence spectrometry (XRF) was used to determine the major and trace elements present in the blackish lutites of the bay bedrock. The major elements identified were, in descending order, Silicon (45.33%), Iron (35.56%), Aluminium (9.24%), Potassium (2.31%), Calcium (2.22%), Titanium (2.15%), Chlorine (2.04%) and Phosphorus (1.12%). Geostatistical analysis revealed strong correlations between organic matter and reduced iron (Fe 2+), tin (Sn), arsenic (As), and sulfur (S). The Banco Bay bedrock is characterized by high sulfur concentrations ranging from 12475 to 75752 ppm, and higher primary bioproductivity at depth than at the surface. Trace elements U, V, and Mo identified an euxinic environment at the water-sediment interface in the subsurface of the bedrock (0-32 m), while at the end of the borehole (78-80 m), a suboxic to anoxic environment was distinguished. These results have enabled us to characterize the bedrock of the Banco Bay.
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Bae, Byeong-Soo, Won-Jong Lee, Kwang-Soo No, Dae-Sung Yoon i Sung-Uk Kim. "Optical Properties of Sol-Gel (Pb,La)TiO3 Thin Films For Waveguide Application". MRS Proceedings 392 (1995). http://dx.doi.org/10.1557/proc-392-279.
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AbstractLead lanthanum titanate ((Pb1−x/100Lax)Ti1−x/400O3, x=10, 20, 28) sol-gel thin films were prepared on SiO2/Si and glass substrates using lanthanum nitrate as a La precursor. The effect of the processing conditions was investigated and the optical properties of the films were measured to obtain good films for waveguide applications. The perovskite crystalline phase is achieved regardless of the heating condition but the slower heating creates better quality films. La content in the film does not effect on the refractive index and transparency of the film.
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Maarof, Saleha, Karim Deraman, W. Nurulhuda W. Shamsuri, Bakar Ismail i S. Asiah Mat. "Microstructure studies of strontium titanate thin films prepared by sol-gel dip coating method". Malaysian Journal of Fundamental and Applied Sciences 9, nr 3 (3.07.2014). http://dx.doi.org/10.11113/mjfas.v9n3.98.
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Strontium titanate (SrTiO3) thin films were deposited on corning glass by using dip coating method. Strontium nitrate, titanium (IV) isopropoxite, ethylene glycol and nitric acid have been use to prepared sol-gel of strontium titanate. Structural and its surface morphologies of the films were characterize by using X-ray Diffraction (XRD) and Atomic Force Microscopy (AFM), respectively. It have been determine that the films were strontium nitrate compound for as-prepared sample with lattice parameter; a = b = c = 0.78 nm and strontium titanate compound for annealing at 500 °C temperature with lattice parameter 0.39 nm. The films annealed at 500 °C showed the films were polycrystalline with orientation; (110), (111), (200) and (211). The grain sizes were in the range of 17.4 to 60.7 nm and surface roughness in range 22.9 to 70.1 nm.
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Wang, Zhuo, J. Huang, S. W. Wang, X. X. Hong, Y. Hou, M. Wang, S. X. Shang, H. Wang, X. B. Hu i Yuguo Wang. "Dielectric Properties of Bi2Ti2O7 Thin Films With (111) Orientation". MRS Proceedings 592 (1999). http://dx.doi.org/10.1557/proc-592-135.
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ABSTRACTBismuth titanate thin films have been prepared on silicon by metalorganic decompositionMOD) technique with bismuth nitrate and titanium butoxide as source materials. The growth procedure of the Bi2Ti2O7 thin films is discussed in this paper. The surface morphology of the Bi2Ti2O7 film was investigated by using Electric Force Microscope (EFM), and the crystallization of the films was studied by x-ray diffraction (XRD). Bismuth titanate thin film prepared on (100) silicon substrate showed strong (111) orientation. Its dielectric properties and the current-voltage (I-V) characteristics were measured. The dielectric constant of the Bi2Ti2O7 thin films vs. frequency, in the temperature range of 100-800 °C, were studied. The dielectric constant and the dielectric loss for Bi2Ti2O7 are 118 and 0.07 respectively at 100KHz. For the Bi2Ti2O7 films with 0.4µm in thickness annealed at 580 °C for 40 minutes, their leakage current density is 4.06×10−7 A/cm2 at an applied voltage of 15V.The ferroelectric phase transition has been observed distinctly and the Curie temperature was determined for the Bi2Ti2O7 ceramic films. Capacitance vs. temperature was measured from 27-800 at 1KHz, 100KHz, 100KHz and 1MHz.
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Chuang, Wen-Hsien, Thomas Luger, Rainer K. Fettig i Reza Ghodssi. "Characterization of Mechanical Properties of Silicon Nitride Thin Films for Space Applications". MRS Proceedings 782 (2003). http://dx.doi.org/10.1557/proc-782-a5.21.
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ABSTRACTMechanical properties of micro-electro-mechanical systems (MEMS) materials at cryogenic temperatures are investigated to extend MEMS devices into space applications. A helium-cooled measurement setup mimicking the outer space environment is developed and installed inside a focused-ion-beam (FIB) system. T-shape, low-stress LPCVD silicon nitride cantilevers suspended on a silicon substrate are fabricated as the test structures using bulk micromachining technique. A lead-zirconate-titanate (PZT) translator and a silicon diode are utilized as an actuator and a temperature sensor in the measurement setup, respectively. The resonant frequencies of an identical cantilever with different “milling masses” are measured to obtain the thickness and the Young's modulus. Additionally, a bending test is performed to determine the fracture strength. From the experiments, the Young's modulus of LPCVD silicon nitride thin films varies from 260.5 GPa ± 5.4 GPa at room temperature (298 K) to 266.6 GPa ± 4.1 GPa at 30 K, while the fracture strength ranges from 6.9 GPa ± 0.6 GPa at room temperature to 7.9 GPa ± 0.7 GPa at 30 K.
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Kabulski, Adam, John Harman, Parviz Famouri i Dimitris Korakakis. "Development of Aluminum Nitride/Platinum Stack Structures for an Enhanced Piezoelectric Response". MRS Proceedings 955 (2006). http://dx.doi.org/10.1557/proc-0955-i15-35.
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ABSTRACTAluminum nitride (AlN) films are being investigated for piezoelectric and high temperature applications, but the piezoelectric response is still much lower than that of more common piezoelectric materials such as lead zirconate titanate or zinc oxide. A method of maximizing the piezoelectric response of aluminum nitride has been explored by depositing stack structures composed of aluminum nitride and platinum. These stack structures were created by depositing a thin, ∼50nm, metal layer in between thicker, ∼150-350nm, layers of the piezoelectric film. Platinum was chosen as the metal interlayer due to the tendency of AlN to become highly c-oriented when deposited on Pt. An electric field was applied across the structure and displacements were measured using a Laser Doppler Vibrometer. A maximum piezoelectric coefficient d33 was found to be over two times larger than the theoretical value for AlN (3.9pm/V). However, some of the stack structures were found to be conductive when measuring the displacement. I-V measurements as well as Fowler-Nordheim theory and plots were applied to investigate tunneling due to high electric fields in the structures.
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Strnad, Nicholas A., Daniel M. Potrepka, Brendan M. Hanrahan, Glen R. Fox, Ronald G. Polcawich, Jeffrey S. Pulskamp, Ryan R. Knight i Ryan Q. Rudy. "Extending atomic layer deposition for use in next-generation piezoMEMS: Review and perspective". Journal of Vacuum Science & Technology A 41, nr 5 (11.07.2023). http://dx.doi.org/10.1116/6.0002431.
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The objective of this work is to describe the current state of the rapidly evolving field of 3D piezoelectric microelectromechanical systems (piezoMEMS), and where it needs to go to fully leverage the potential performance benefits offered by atomic layer deposition (ALD). We define 3D piezoMEMS as the application of piezoelectric ALD films to 3D, high aspect-ratio, mechanically pliable structures. Since there are so few existing reports of 3D piezoMEMS, a literature review of ALD films applied to conventional microelectromechanical system (MEMS) devices is given. ALD processes for piezoelectric thin films are reviewed in the context of relevant applications such as transducers and actuators. Examples include aluminum nitride, hafnium zirconate, doped-hafnia, lead zirconate-titanate, lead hafnate, and lead hafnate-titanate. New concepts for ALD-enabled 3D piezoMEMS actuators are presented with supporting theoretical calculations that show that chip-scale mechanical work densities could be improved by ≫10× compared to conventional planar piezoMEMS. 3D fabrication methods are also discussed, while the future needs of atomic layer processing are highlighted.
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Raptakis, Adam, Lefteris Gounaridis, Jörn P. Epping, Thi Lan Anh Tran, Thomas Aukes, Moritz Kleinert, Madeleine Weigel i in. "Integrated heterodyne laser Doppler vibrometer based on stress-optic frequency shift in silicon nitride". PhotoniX 4, nr 1 (21.09.2023). http://dx.doi.org/10.1186/s43074-023-00105-4.
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AbstractWe demonstrate a compact heterodyne Laser Doppler Vibrometer (LDV) based on the realization of optical frequency shift in the silicon nitride photonic integration platform (TriPleX). We theoretically study, and experimentally evaluate two different photonic integrated optical frequency shifters (OFSs), utilizing serrodyne and single-sideband (SSB) modulation. Both OFSs employ stress-optic modulators (SOMs) based on the non-resonant piezoelectrical actuation of lead zirconate titanate (PZT) thin-films, deposited on top of the silicon nitride waveguides with a wafer-scale process. To improve the modulation bandwidth of the SOMs we investigate a novel configuration of the electrodes used for the actuation, where both electrodes are placed on top of the PZT layer. Using this top-top electrode configuration we report frequency shift of 100 kHz and 2.5 MHz, and suppression ratio of the unwanted sidebands of 22.1 dB and 39 dB, using the serrodyne and the SSB OFS, respectively. The best performing SOM structure induces 0.25π peak-to-peak sinusoidal phase-shift with 156 mW power dissipation at 2.5 MHz. We use the SSB-OFS in our compact LDV system to demonstrate vibration measurements in the kHz regime. The system comprises a dual-polarization coherent detector built in the PolyBoard platform, utilizing hybrid integration of InP photodiodes (PDs). High quality LDV performance with measurement of vibration frequencies up to several hundreds of kHz and displacement resolution of 10 pm are supported with our system.
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Justice, J. L., O. M. Mukdadi i D. Korakakis. "Surface Acoustic Wave Sensors Deposited on AlN Thin Films". MRS Proceedings 1202 (2009). http://dx.doi.org/10.1557/proc-1202-i09-08.
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AbstractOver the past few decades, there has been considerable research and advancement in surface acoustic wave (SAW) technology. At present, SAW devices have been highly successful as frequency band pass filters for the mobile telecommunications and electronics industries. In addition to their inherent frequency selectivity, SAW devices are also highly sensitive to surface perturbations. This sensitivity, along with a relative ease of manufacture, makes SAW devices ideally suited for many sensing applications including mass, pressure, temperature, and biosensors. In the area of biosensing, surface plasmon resonance (SPR) and quartz crystal microbalances (QCM) are still in the forefront of research and development, but advancement in SAW sensors could prove to have significant advantages over these technologies. This study investigates the advantages of using aluminum nitride (AlN) as a material for SAW sensors. AlN retains its piezoelectric properties at relatively high temperatures when compared to more common piezoelectric materials such as lead zirconium titanate (PZT), lithium tantalate (LiTaO3) and zinc oxide (ZnO). AlN is also a very robust material making it suitable for biosensing applications where the sensing target is selectively absorbed by an active layer on the device which may attack the piezoelectric layer. AlN thin films of different thicknesses have been deposited on Si substrates by DC reactive sputtering. Rayleigh-wave SAW devices have been fabricated by the deposition of platinum contacts and interdigital transducers (IDTs) onto AlN thin films using standard photolithographic processes. Experiments have been conducted to measure Rayleigh velocities, resonant frequencies, and insertion loss. Experimental results are compared to theoretical calculations.
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Kosugi, M., R. Obata, K. Suzuki, K. Kuroyama, S. Du, B. Skinner, T. Kikkawa i in. "Gate-tunable resistance drops related to local superconducting gaps in thin TaS2 layers on SrTiO3 substrates". APL Materials 11, nr 8 (1.08.2023). http://dx.doi.org/10.1063/5.0147818.
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Strontium titanate [SrTiO3 (STO)], a perovskite oxide with an extremely high gate-tunable dielectric constant (ε) due to quantum paraelectric phases, is attracting considerable attention for yielding various physical phenomena when two-dimensional (2D) layers are integrated. Superconductivity is such a typical phenomenon. However, the influence of the STO substrates on enhancing transition temperatures (Tc) for (atomically) thin 2D flakes attached to them has been rarely investigated. Here, we report gate-tunable and gradual four-terminal resistance drops with critical onset T (TCR) and scanning tunneling spectroscopy (STS) spectra in devices comprising thin TaS2 flakes attached on monolayer hexagonal boron nitride (hBN) spacer/STO substrates. Observation of STS spectra confirms the presence of local superconducting gaps Δ (∼1.5 meV) with transition T (TΔC) three-times higher than previous reports of Tc under absent pressure and strong position dependence of Δ. Depending on Δ on back gate voltages (Vbg) and magnetic fields, there is a strong correlation between TCR and the onset Tc of superconductivity, implying an enhancement of approximately five times compared with the previous highest-onset Tc values without pressure as the applied Vbg increases. The high onset Tc and Δ are discussed based on screening of the long-range Coulomb interaction (CI) due to the high-ε of SrTiO3, while the short-ranged CI remains strong in the 2D limit, causing the superconductivity. Using a monolayer hBN/SrTiO3 substrate with Vbg opens doors to Tc enhancement in thin superconducting layers integrated on it and wide application due to the solid-state high-ε substrates.
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Gatea, Hamed A. "Effect of Substrate-induced Strains on Ferroelectric and Dielectric Properties of PZT Films Prepared by Sol-Gel Technique". Nanoscience & Nanotechnology-Asia 10 (15.07.2020). http://dx.doi.org/10.2174/2210681210999200715105250.
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Background: Lead Zirconate Titanate (PZT) films were synthesized by sol gel technique. The growth of films on ITO, Si\SiO2\Ti\Au, Si\Au and Si\SiO2\Ti\Al substrates discussed. In this study, Zirconium nitrate, lead acetate, and Ti (IV) isoproxide used as raw materials. Besides, acetic acid used as a solvent and 2-methoxy ethanol used as a stabilizer for Ti structure. Along with this, PZT films have perovskite structure, thin-film perovskite structure with high dielectric properties and hysteresis loop have been investigated. Methods: The effects of the type’s substrate on dielectric properties the ferroelectric properties were investigated and compared PZT film which deposited in different substrates. The films annealed at 600 C to complete crystalline films. XRD shows tetragonal PZT films have a strong perovskite structure with [100] prefer plane orientation. SEM and crosssection technique used to study for PZT surface films. Results: The dielectric constant at room temperature was different values depending on the types of substrate. The dielectric properties of the PZT films measured at 1 kHz were 120-400 dielectric constant and dielectric loss 0.02-0.08 at room temperature and 1 kHz. Conclusion: The largest remnant polarization (Pr) and coercive field (Ec) are obtained for PZT film deposited on Si\SiO2\Ti\Au substrate, equal to 26.6 mC/cm2 and 38.3 kV/cm, as compared to 16.3 mC/cm2 and 32.2 kV/cm2 for PZT film deposited on ITO substrate.
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Malyshev, Kushchevska i Bruskova. "STATE, TRENDS, AND STRUCTURE OF THE WORLD NANO-POWDER MARKET". Visnyk Universytetu “Ukraina”, 2019. http://dx.doi.org/10.36994/2707-4110-2019-3-24-06.
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The purpose of this study is to provide a comprehensive analysis of the global nanopowder market. Materials and methods. The study used such research methods as system-logical method, method of statistical generalization, comparative and factor analysis. Research results. It is known that nanopowders are obtained by chemical, physical, physico-chemical and mechanical methods. One of the major problems in the production of nanopowders is the tendency of nanoparticles to form aggregates and agglomerates that complicate the production of compact materials. To overcome the forces of agglomeration, a mechanical force or an increase in the sintering temperature must be applied. According to estimates from the consulting company Lux Research, in 2012, the nanotechnology market was $ 190.3 billion. Its annual growth is 15-17%. The world market leaders are the United States ($ 59 billion), Europe ($ 47 billion) and the Asia Pacific region ($ 9.4 billion). The US is the leader in both the commercial market and the number of publications (about 25,000 in 2015) and patents in nanotechnology (45% of patents). Following the results of 2015, more than $1.4 trillion worth of nanotechnology products were manufactured. In the structure of production of nanoproducts the chemical industry, scientific researches (intermediary products, as a rule, not serial) and electronics are leading. Global investments in nanotechnology in 2015 totaled $ 18.1 billion. This indicator increased by 18% compared to 2013. Corporate investments ($ 8.6 billion) became the main source of financing (public - only $ 8.3 billion). The leaders in terms of public investment are the US and the EU. Experts estimate that, by 2020, investment leadership may shift to Japan. Today, the leader in the nanomaterials market is the United States with a projected revenue level of 2018 of $ 1.46 billion. The main products on the world market for nanopowders are metal oxide powders. In the product group of metal oxides 4/5 the production volume accounts for the three most common types of raw materials: silica (SiO2), titanium dioxide (TiO2) and alumina (Al2O3). At the same time, silica occupies more than half of all production, alumina - 18% and titanium dioxide - 10%. The most available oxides are oxides of iron, zinc, cerium, zirconium, cuprum, magnesium, yttrium. The most complex oxides and mixtures are: tin oxide, barium titanate, cobalt carbide, silicon nitride and indium tin oxide. An analysis of the patents presented for nanopowder research has shown that the most promising area of scientific development is aluminum and precious metal nanopowders. Conclusions. Analysis of the world nanopowder market makes it possible to identify the following indicators that characterize its development: the common problem in the nanomaterials market is high cost of production, low volume of production and accessibility for the end consumer; the most developed nanopowder markets: USA, Europe and Asia-Pacific; projected growth rates during 2015-2020 The three largest components of the nanomaterials market: energy, production of catalysts, structural materials - 60%, 13% and 30% respectively; production of metal oxide products prevails in the world market of nanopowders; the most common types of raw materials: silica) - more than half of all production, titanium dioxide - 10% and alumina - 18%.