Academic literature on the topic 'Method of etching in the presence of metals'
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Journal articles on the topic "Method of etching in the presence of metals"
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Pashangeh, Shima, Seyyed Sadegh Ghasemi Banadkouki, Fatemeh Besharati, Fatemeh Mehrabi, Mahesh Somani, and Jukka Kömi. "Color Light Metallography Versus Electron Microscopy for Detecting and Estimating Various Phases in a High-Strength Multiphase Steel." Metals 11, no. 6 (May 23, 2021): 855. http://dx.doi.org/10.3390/met11060855.
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In this study, fresh attempts have been made to identify and estimate the phase constituents of a high-silicon, medium carbon multiphase steel (DIN 1.5025 grade) subjected to austenitization at 900 °C for 5 min, followed by quenching and low-temperature bainitizing (Q&B) at 350 °C for 200 s. Several techniques were employed using different chemical etching reagents either individually (single-step) or in combination of two or more etchants in succession (multiple-step) for conducting color metallography. The results showed that the complex multiphase microstructures comprising a fine mixture of bainite, martensite and retained austenite phase constituents were selectivity stained/tinted with good contrasting resolution, as observed via conventional light optical microscopy observations. While the carbon-enriched martensite-retained austenite (M/RA) islands were revealed as cream-colored areas by using a double-step etching technique comprising etching with 10% ammonium persulfate followed by etching with Marble’s reagent, the dark gray-colored bainite packets were easily distinguishable from the brown-colored martensite regions. However, the high-carbon martensite and retained austenite in M/RA islands could be differentiated only after resorting to a triple-step etching technique comprising etching in succession with 2% nital, 10% ammonium persulfate solution and then warm Marble’s reagent at 30 °C. This revealed orange-colored martensite in contrast to cream-colored retained austenite in M/RA constituents, besides the presence of brown-colored martensite laths in the dark gray-colored bainitic matrix. A quadruple-step technique involving successive etching with 2% nital, 10% ammonium persulfate solution, Marble’s reagent and finally Klemm’s Ι reagent at 40 °C revealed even better contrast in comparison to the triple-step etching technique, particularly in distinguishing the RA from martensite. Observations using advanced techniques like field emission scanning electron microscopy (FE-SEM) and electron back scatter diffraction (EBSD) failed to differentiate untempered, high-carbon martensite from retained austenite in the M/RA islands and martensite laths from bainitic matrix, respectively. Transmission electron microscopy (TEM) studies successfully distinguished the RA from high-carbon martensite, as noticed in M/RA islands. The volume fraction of retained austenite estimated by EBSD, XRD and a point counting method on color micrographs of quadruple-step etched samples showed good agreement.
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Llorca-Isern, Núria, Ana Maria Escobar, and Oriol Rius. "Scalable Methods to Obtain Superhydrophobicity onto Metallic Surface." Materials Science Forum 879 (November 2016): 2501–6. http://dx.doi.org/10.4028/www.scientific.net/msf.879.2501.
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Superhydrophobic surfaces, with extremely high water contact angles (CAs) of more than 150° are of special interest due to their various anti-adhesive and self-cleaning properties. Recent studies demonstrate that the superhydrophobicity principally results from the presence of binary structures at both the micrometre and nanometre scales together with the low-energy wax-like materials on the surfaces. Materials with similar properties, to those of the lotus leaf structure are very useful in several areas, such as the aeronautical industry and civil engineering; so many methods have been developed to mimic the lotus leaf structure. Metals are very important and irreplaceable engineered materials in many industrial fields. An alternative method for enhancing superhydrophobicity on different metals is proposed. The method proceeds by coating the metallic surface with a superhydrophobic reactive such as dodecanoic acid being a common application its use in paints with eco-friendly properties. The goal of this study is to induce direct superhydrophobicity by a single step and coating process on prepared surfaces of pure commercial aluminium 99.9 wt %, pure commercial 99.9 wt % copper and stainless steel grade 316L (UNS S31603). The chemical reaction proceeds by etching the activated surface with lauric acid in ethanol solutions.
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Abdulkadir, Auwal, Nur Afidah Md. Noor, Azlan Abdul Aziz, and Mohd Zamir Pakhuruddin. "Broadband Anti-Reflection in Black Silicon Fabricated by Two-Step Silver-Assisted Wet Chemical Etching for Photovoltaics." Solid State Phenomena 301 (March 2020): 167–74. http://dx.doi.org/10.4028/www.scientific.net/ssp.301.167.
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This paper reports broadband anti-reflection in black silicon (b-Si) fabricated by two-step metal-assisted chemical etching (MACE) for potential photovoltaic (PV) applications. The method involves deposition of silver nanoparticles (Ag NPs) in aqueous solution of HF:AgNO3, followed by etching in HF:H2O2:DI H2O solution for different duration (10-25 s). Effects of etching time towards surface morphological and optical properties of b-Si nanowires are investigated. Surface morphological characterization confirms presence of b-Si nanowires with heights of 350-570 nm and diameter of 150-300 nm. The b-Si nanowires exhibit outstanding broadband anti-reflection due to refractive index grading effect. This is represented as weighted average reflection (WAR) in the 300-1100 nm wavelength region. After 20 s of etching, b-Si nanowires with height of 570 nm and width of about 200 nm are produced. The nanowires demonstrate WAR of 5.5%, which represents the lowest WAR in this investigation. This results in absorption of 95.6% at wavelength of 600 nm. The enhanced broadband light absorption yields maximum potential short-circuit current density (Jsc(max)) of up to 39.7 mA/cm2, or 51% enhancement compared to c-Si reference. This facile b-Si fabrication method for broadband enhanced anti-reflection could be a promising technique to produce potential PV devices with high photocurrent.
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Adibah, Nurulain A., S. N. Azella, and M. F. Abd Shukur. "Synthesis of Ti3C2 Mxene through In Situ HF and Direct HF Etching Procedures as Electrolyte Fillers in Dye-Sensitized Solar Cell." Materials Science Forum 1023 (March 2021): 15–20. http://dx.doi.org/10.4028/www.scientific.net/msf.1023.15.
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MXene is the new family of two-dimensional (2D) transition metal carbides, carbonitrides and nitrides discovered in 2011. The unique properties of 2D MXene such as excellent mechanical properties, hydrophilic surfaces and metallic conductivity made it interesting for application in electrodes of rechargeable batteries, supercapacitors, photocatalysts, catalysts, transparent conducting films, and flexible high-strength composites. The MXene can be synthesized through a selective etching process by using either in-situ HF (hydrofluoric acid) or direct HF methods. This study reports on the effect of the in-situ HF and direct HF etching procedures on the morphology of the synthesis Ti2C3 MXene using titanium aluminum carbide (Ti2AlC3) as precursor. The morphology and elements presence were evaluated by using variable pressure field emission scanning electron microscope (FESEM) and energy dispersion X-ray (EDX) spectroscopy analyses, respectively. The analysis shows that the MXene synthesized through the direct HF method was successfully delaminated compared to the in-situ HF procedures.
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Frolov, Ivan N., Sergey L. Zabudkov, Andrey V. Yakovlev, and Marina I. Lopukhova. "SELECTION OF MODE OF ANODIC TREATMENT OF GRAPHITE IN A SPENT NITRIC ACID ETCHING SOLUTION FOR PRODUCING THERMALLY EXPANDING GRAPHITE COMPOUNDS." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 62, no. 6 (July 8, 2019): 77–83. http://dx.doi.org/10.6060/ivkkt.20196206.5873.
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The possibility of using galvanic waste for the synthesis of graphite thermo expanded compounds has been shown. An electrolyte on the basis of a spent nitrate solution of etching copper parts containing cations of various metals in its composition was taken as an example, thereby solving an environmental issue related to the problem of utilization of solutions containing nitric or sulfuric anions in its composition. The processes occurring in the synthesis of thermally expanding graphite compounds on platinum and graphite electrodes in the electrolyte under investigation were studied by the method of potentiodynamic curves. The currents on the potentiodynamic curves before reaching the oxygen evolution potential were due to the oxidation of the surface-functional groups followed by intercalation of the graphite matrix. It was revealed that the potential for oxygen evolution in the electrolyte based on the spent nitric acid solution of etching of copper parts is slightly lower than in 58% HNO3 due to the presence of metal cations in the composition. Free metal cations attract a part of water molecules to form hydrate shells, while copper cations form complexes where H2O molecules are ligands, which makes it difficult to release oxygen. In the electrochemical synthesis of thermally expanding graphite compounds, potentiostatic and galvanostatic modes were applied. A range of potentials of 1.8 - 2.2 V was chosen for performing the synthesis in the potentiostatic mode. Recommendations are given for the application of the galvanostatic mode with the current of anodic treatment of 60 - 140 mA (per 1 g of graphite) for the synthesis of graphite thermo expanding compounds in industrial volumes. The thermo expanded graphite obtained in this manner is characterized by a bulk density of less than 2 g/dm3.
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Pustovoit, V. N., and Yu V. Dolgachev. "REVISITING THE NATURE OF SITES OF MARTENSITE NUCLEATION DURING STEEL HARDENING." Izvestiya. Ferrous Metallurgy 62, no. 2 (March 30, 2019): 109–14. http://dx.doi.org/10.17073/0368-0797-2019-2-109-114.
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Presence of microvolumes most prepared for the martensite emergence in austenite is discussed. Aming many works dealing with martensitic transformations, rare works are devoted to the location of martensite origin. This aspect of transformation is important, since it allows us to obtain new knowledge about scenarios for γ → α transformation development during quenching of steel. The martensite embryos are submicron austenite volumes that are most prepared for phase transition and are characterized by increased energy. Experimental results were obtained by the methods of high-temperature metallography. Steel structure observed as a result of vacuum etching was studied, as well as the surface relief caused by shear during the martensitic transformation. The resulting structural patterns made it possible to observe most of the possible places for martensite emergence: nonmetallic inclusions, twins, high-angle and small-angle grain boundaries, previously formed martensite crystals, dislocations and elements of the disclination structure. It is shown that a high dislocation density is observed in the twin area, which facilitates nucleation of martensite as a result of disappearance of part of elastic energy of the dislocation when atoms inside the embryo are rearranged. When nucleation occurs on the grain boundaries, energy is released, which is used to construct a new interphase boundary and to compensate emerging elastic energy. The relative energy of the boundaries of different types was estimated by the method of multi-beam interferometry. The depth of the grooves that were formed on the surface by thermal etching was measured. Elements of disclination structure resulting from inhomogeneous deformation were observed, which are also sites of germinal centers formation. It is noted that nanoareas with ferromagnetic order, which are present in paramagnetic austenite, may not be observed with the help of the technique used in this work. However, magnetism plays a decisive role in realization of one or another scenario of the development of phase transformation in steels. Obtaining data on the interaction of ferromagnetic areas in austenite with each other, with crystal lattice defects, the magnetic field, and data on their lifetime, number and size is an important task for future research.
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Ovchinnikov, Victor, and Andriy Shevchenko. "Self-Organization-Based Fabrication of Stable Noble-Metal Nanostructures on Large-Area Dielectric Substrates." Journal of Chemistry 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/158431.
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A cost-effective fabrication of random noble-metal nanostructures with a feature size of the order of 10 nm on a large-area dielectric substrate is described. The method combines dry etching of the substrate through a self-organized metal mask with a directional deposition of a multilayered metal film. The technique allows one to create metal nanoislands on a nanopatterned dielectric template with an enhanced adhesion between the metal and the dielectric. The use of the adhesion layer—that makes the structures stable—is important in view of variety of optical and other potential applications of the structures. We observe that the presence of the adhesion sublayer dramatically influences both the morphological and optical properties of the structures. The results of this work can be of interest in regard to the development of new approaches to self-organization-based nanofabrication of extremely small metal and metal-dielectric nanostructures on large-area substrates.
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Cai, Yina, Binxue Ren, Chifang Peng, Cunzheng Zhang, and Xinlin Wei. "Highly Sensitive and Selective Fluorescence “Turn-On” Detection of Pb (II) Based on Fe3O4@Au–FITC Nanocomposite." Molecules 26, no. 11 (May 26, 2021): 3180. http://dx.doi.org/10.3390/molecules26113180.
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New nanocomposites, Fe3O4@Au–FITC, were prepared and explored to develop a fluorescent detection of Pb2+. The Fe3O4@AuNPs–FITC nanocomposites could be etched by Pb2+ in the presence of Na2S2O3, leading to fluorescence recovery of FITC quenched by Fe3O4@Au nanocomposites. With the increase of Pb2+ concentration, the fluorescence recovery of Fe3O4@AuNPs–FITC increased gradually. Under optimized conditions, a detection limit of 5.2 nmol/L of Pb2+ with a linear range of 0.02–2.0 µmol/L were obtained. The assay demonstrated negligible response to common metal ions. Recoveries of 98.2–106.4% were obtained when this fluorescent method was applied in detecting Pb2+ spiked in a lake-water sample. The above results demonstrated the high potential of ion-induced nanomaterial etching in developing robust fluorescent assays.
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Lutsik, Vladimir I., Yury V. Chursanov, and Anatoly V. Starovoytov. "INFLUENCE OF FORMATION OF THE COMPLEXES WITH DIFFERENT KIND OF LIGANDS ON KINETICS OF OXIDATIVE DISSOLUTION OF METALS." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 61, no. 8 (August 21, 2018): 22. http://dx.doi.org/10.6060/ivkkt20186108.5690.
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Rotating disk method has been used to study the dissolution of gold in the presence of an oxidizer and a mixture of dissimilar ligandforming reagents. Kinetic regularities of gold dissolution were investigated in aqueous systems thiourea-thiocyanate with Fe (III) and Cu (II) ions as the oxidizer; thiosulfate-thiocyanatewithFe(III)EDTA oxidizing complex and thiosulfate-thiocyanate with ammonia complex [Cu(NH3)4]2+ asoxidizing agent. Peculiarities of these mixed systems is a possibility to form the monoligandas as well as geteroligand complexes of gold. The influence of gold complexes formation with different sorts of ligands on the metal dissolution rate have been considered. The dependence of the dissolution rate on the ratio of ligands concentrations and on the oxidizing agent nature was investigated. Interrelation was established: the use of dissimilar ligandforming reagents - the higher thermodynamic stability of the geteroligand complexes of gold (relative to the homoligand ones) - synergistic increase of the gold dissolution rate. It was found that the heterophase reaction makromechanism for the thiourea-thiocyanate-Fe(III) system is determined by the proximity of the rates of chemical and diffusion stages (experimental activation energy - 21.6 kJ/mol; the reaction order in respect to the disk rotation frequency – 0.23). Diffusive limitation is due to the slow withdrawal of the reaction products -Au (I) compounds - from the solid phase surface. The formation of stronger heteroligand complexes and the corresponding increase in the reaction products concentration at the surface increases a rate of the metal diffusion into the solution. For the thiourea-thiosulfate-Fe(III)EDTA system a film formation of the reaction solid products on the gold surface was observed. To identify it the infrared reflection spectra of the polished gold surface after the etching were obtained. There is a strong absorption band on the spectra at 804 cm-1. Absorption in this area has been associated with the stretching vibrations of C=S bond of the thiourea molecules joined to the surface and the products of their oxidation.
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SKVORTSOV, Arkadiy A., Evgeniya O. GNATYUK, Margarita R. RYBAKOVA, and Ivan V. BURUKIN. "METHODS FOR HARDENING AND IMPROVEMENT OF FATIGUE CHARACTERISTICS OF TITANIUM AND IRON-CHROMIUM NICKEL ALLOY SAMPLES." Periódico Tchê Química 17, no. 35 (July 20, 2020): 425–36. http://dx.doi.org/10.52571/ptq.v17.n35.2020.37_skvortsov_pgs_425_436.pdf.
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This work describes the procedure for determining residual surface stresses using the mechanical method and four methods of hardening samples. The urgency of the problem stated in the article is due to the fact that surface tensile stresses arising in the manufacture of highly loaded parts can significantly reduce the mechanical, resource and fatigue characteristics of products. The aim of the study was to harden samples of titanium and iron-chromium-nickel alloys to improve their strength, fatigue and resource characteristics and determine residual stresses by layer-by-layer removal of the studied layers by electrochemical etching. The determination of surface residual stresses was carried out mechanically using a measuring and calculation complex during continuous etching of the metal from the test surface of the sample, which made it possible to measure the residual stresses at different depths and determine the energy of the surface stress state. Residual stresses were calculated from the deformation of the remaining part of the sample with a change in the depth of the studied layers. The hardening of the samples was carried out in four ways, namely: ultrasonic hardening; ultrasonic curing + Rosler (vibration processing); Rosler (vibration processing) + ultrasonic curing; Rosler (vibration processing) + ultrasonic hardening. The results of the study showed that the surface of the products is a weaker area than the inside. After quenching, surface compressive stresses arise for all samples of titanium and iron-chromium-nickel alloys. The preferred case of hardening is the second (ultrasonic hardening + centrifugal hardening). The presence of residual compressive stresses in the outer layers of the products increases their fatigue limit by ≈20%. The results of the work can be used to manufacture products with high mechanical, resource and fatigue characteristics.
Dissertations / Theses on the topic "Method of etching in the presence of metals"
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Федоров, Антон Олександрович. "Час життя в пористих структурах з нанокристалами металів." Bachelor's thesis, КПІ ім. Ігоря Сікорського, 2019. https://ela.kpi.ua/handle/123456789/28877.
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Загальний обсяг роботи складає 72 сторінки, кількість ілюстрацій - 32, таблиць - 2, джерел за переліком посилань - 18.
Час життя носіїв неврівноважених носіїв заряду є важливим параметром для напівпровідникових приладів та пристроїв. Зазвичай вважається, що присутність металів в кремнії призводить до погіршення об’ємних властивостей напівпровідника.
В останні три десятиліття почав набувати популярності такий матеріал як пористий кремній, одним із способів отримання якого є хімічне травлення в присутності металів.
Метою роботи є дослідження часу життя неврівноважених носіїв заряду в пористому кремнії, виготовленому методом хімічного травлення в присутності металів. Важливим факторов є присутність різних металів при травленні крепнію.
Для здійснення дослідження необхідно про зробии наступне:
• Провести огляд літератури та ознайомитися с особливостями пористого кремнію та методами його виготовлення.
• Виготовити достатню кількість різноманітних зразків пористого кремнію
• Провести виміри часу життя
• Зробити висновки щодо отриманох під час дослідження інформації
Об’єктами дослідження є зразки пористого кремнію, що містять ту чи іншу кількість металічних речовин.
У роботі було виористано наступні методи дослідження:
• Отримання реалксаційної характеристики носіїв заряду методом модцляції в точковому контакті.
• Вимірювання опору зразків
• Вивчення морфології зразків сенсорів за допомогою растрової електронної мікроскопії.
Наукова новизна полягає у дослідженні параметрів пористого кремнію, протравленного саме в присутності Ag, Au та Cu з подальшим видаленням металічних наночасток у деяких випадках.The total amount of work is 72 pages, number of illustrations - 32, tables - 2, bibliographic titles - 18. The lifetime of carriers of unbalanced charge carriers is an important parameter for semiconductor devices and devices. It is generally believed that the presence of metals in silicon leads to a deterioration of the bulk properties of the semiconductor. In the last three decades, such material has become popular as porous silicon, one of the methods of obtaining which is chemical etching in the presence of metals. The purpose of this work is to study the lifetime of unbalanced charge carriers in porous silicon made by the method of chemical etching in the presence of metals. Important factors are the presence of various metals during etching. To conduct the study, you must do the following: • To conduct a review of the literature and get acquainted with the features of porous silicon and methods of its manufacture. • To produce a sufficient number of different samples of porous silicon • Take measurements of life time • Make conclusions about the information obtained during the study The objects of the study are samples of porous silicon containing one or another amount of metallic substances. The following research methods were developed in the work: • Obtaining a realxication characteristic of charge carriers by a method of modulation in point contact. Measuring the resistance of the samples • Studying the morphology of sensor samples using raster electron microscopy. The scientific novelty consists in studying the parameters of porous silicon, etched precisely with help of metal chemical assisting etching with Ag, Au, and Cu, with the subsequent removal of metallic nanoparticles in some cases.
Book chapters on the topic "Method of etching in the presence of metals"
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Dadwal, Uday, and Rajendra Singh. "Silicon-Silver Dendritic Nanostructures Enabled Photoelectrochemical Solar Water Splitting for Energy Applications." In Silver Micro-Nanoparticles - Properties, Synthesis, Characterization, and Applications. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.95934.
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Photoelectrochemical (PEC) splitting of natural water was studied using silicon nanowires decorated with silver dendrites (dendritic nanostructures) as working electrode. A metal assisted wet chemical etching method has been used for the synthesis of dendritic heteronanostructures. Measured photocurrent density 1.7 mA/cm2 under white light illumination exhibits the efficient decomposition of natural water. The decomposition of water is primarily ascribed to the enhancement in the working electrode surface and water effective interface and the decrease in the recombination of light induced (photoexcited) carriers in the existence of silver dendritic nanostructures. Enhancement in photoinduced charge carriers separation caused due to the existence of Schottky barrier between the silicon and silver dendritic nanostructures. The light induced carriers (holes) in silicon are transferred to the metal (Ag) dendritic nanostructures that work as a charge basin to effectively carry out the oxidation reaction of water during PEC measurement. The solar-to-hydrogen (STH) conversion efficiency of about 4.5% was reported, indicating the efficient PEC solar water (pH 7) splitting. A cost-effective and efficient method for the PEC solar water splitting is presented in order to enhance the STH efficiency for the production of clean and renewable fuel.
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Cristina Vasconcelos, Helena. "Optical Nonlinearities in Glasses." In Nonlinear Optics - Nonlinear Nanophotonics and Novel Materials for Nonlinear Optics. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.101774.
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The field of photonics has been the target of constant innovations based on a deep knowledge of the nonlinear optical (NLO) properties of materials and especially on information/data technologies. This chapter compiles some of the main physical aspects needed to understand NLO responses, especially in glasses. Any deviation from the linear correlation between a material’s polarization response and the electric component of an applied electromagnetic field is an example of nonlinear optic behavior. Heavy metal oxide and chalcogenide glasses offer the largest nonlinear response. For example, high refractive index and high dispersion glasses fall in the type of non-resonant devices, while the resonant ones comprise metal nanoparticle doped glasses. Metal nanoparticles’ doped glasses can be pre- pared by the sol-gel method. The optical absorption spectrum of Ag-doped silica glass shows the presence of an absorption band of surface Plasmon Resonance due to Ag nanoparticles at 420 nm and Z-scan has been used to study the NLO properties. This chapter contains a brief discussion of the basic principles of nonlinear optics, the review of the nonlinear optical of glass in general, and two separate sections concerning the nonlinear optical effects in the glasses doped with quantum dots and metals, respectively.
Conference papers on the topic "Method of etching in the presence of metals"
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Zeng, Hongjun, Alan Feinerman, and Zhiliang Wan. "A Sacrificial Method for Fabricating Microchannel Accelerated by Galvanic Corrosion." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-81124.
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A metal sacrificial method has been investigated for creation of microchannels by galvanic corrosion in a metal multilayer. To achieve the fastest sacrificial metal combination, different metals and the corresponding etchants are chosen. Channels from 50 μm to 1 μm wide, 0.2 μm high, and 1500 μm long, as well as the channel array is fabricated, using Cr/Cu galvanic metal couple as sacrificial material. The relationship between the etching front vs. the etching time, and the relationship of the etch rate vs. channel width is measured and compared with the etching performance of the single metal. The measurement shows there is approximately 10 times faster etching in the galvanic coupled metals than that in the single metal. SEM images of the channels and channel array made by this method are presented. This method is compatible with the conventional VLSI process, and has the potential for fabricating microchannels with submicron or even nanometer cross section.
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Cerchiara, R. R., P. E. Fischione, M. F. Boccabella, and A. C. Robins. "Automated Sample Preparation of Packaged Microelectronics for FESEM." In ISTFA 2008. ASM International, 2008. http://dx.doi.org/10.31399/asm.cp.istfa2008p0280.
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Abstract A packaged device based on a ball grid array or other design presents a challenge to the failure analyst. Accessing one of the metal levels from the topside requires decapsulation by either a wet, predominantly dry (RIE) or a completely dry (mechanical) treatment. To reveal the details of the gate including the gate oxide, new approaches to selective etch delineation by RIE are required. This article presents an automated sample preparation method for packaged microelectronic materials by combining plasma cleaning, ion beam etching, reactive ion etching and ion beam sputter coating. A single etch gas chemistry was effective in phase delineation by RIE. Future work to further delineate the gate oxides could support accurate metrology by means of FESEM rather than field emission transmission electron microscope.
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Zhang, Zhengyu, Yongxiang Hu, and Zhenqiang Yao. "An Experiment-Based Model to Determine Eigenstrain in Fibre Metal Laminates Induced by Laser Peen Forming." In ASME 2016 11th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/msec2016-8544.
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Fibre metal laminates are new sorts of composite materials with superior fatigue and impact properties. Forming parts from FMLs is very attractive to reduce the process cycle and labor cost. Laser peen forming (LPF) is a promising method to form FMLs with its design flexibility and adaptability to produce complex shapes. To predict the deformed shape of FMLs after laser peen forming, eigenstrain-based modelling is a helpful method with advantage in spending less computational time, but it is difficult to precisely determine eigenstrain distribution regarding material with layered structure. In the present research, an efficient and effective experiment-based method is proposed to determine eigenstrain in the metal layer of FMLs, which can avoid the complicated numerical simulation. The determined eigenstrain is assumed to be uniformly distributed in each metal layer while no plastic deformation is generated in composite layer due to its high strength yield. An analytical model is developed to relate the bending deformation to eigenstrain field. Firstly, the equivalent external bending moment applied on the samples is deduced from eigenstrain, and then the relation of deformation and bending moment is provided by a beam bending model. Chemical etching is utilized to remove metal layer by layer to calculate eigenstrain in each layer. With removal of each metal layer, the bending profiles will spring back or bend further due to change of applied moment and bending stiffness. The eigenstrain in each layer can be inversely determined by matching the residual bending profile after each etching with the developed bending model. One scanning strategy of LPF with reciprocating line and 50% overlapping rate is performed in experiments to apply laser shocks on the entire top surface of strip samples, which are prepared from glass laminate aluminum reinforced epoxy with a unidirectional orientation. Eigenstrain in the top and bottom metal layer is successively determined by the proposed analytical model and chemical etching. Finite element analysis is utilized to verify the determined eigenstrain by comparing the simulated shape with experiments and good agreement is obtained.
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Shin, Heungjoo, and Peter J. Hesketh. "Micro Four-Point Probe With Metal Tip." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-42443.
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A fabrication method for a metal micro four-point probe with metal tip and measurements made using this probe are presented. A novel conical metal tip etching method using silicon dioxide chamber is also introduced. Four-point-probe resolution is decided by the electrode spacing because the effective probing depth is proportional to the electrode spacing [1]. AFM (Atomic Force Microscope) cantilever type micro four-point probe can be installed in the commercial AFM to measure the sample resistivity with low contact force and high resolution [2]. The integration of a vertical tip extends the useful application of micro four-point-probe. A conductive tip can be fabricated by coating a dielectric cantilever with conductive material. However, solid electric contact between sample and cantilever tip cannot be ensured because of the possibility of tip coating material wear. The effect of conductivity loss due to wear can be reduced with a solid metal tip.
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Vanzi, M., A. Bonfiglio, P. Salaris, P. Deplano, E. F. Trogu, A. Serpe, G. Salmini, and R. De Palo. "Selective Au-Etching on Aged GaAs-Based Devices." In ISTFA 1999. ASM International, 1999. http://dx.doi.org/10.31399/asm.cp.istfa1999p0211.
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Abstract A specific problem in failure analysis of InGaAs/ AlGaAs laser diodes asked for a deprocessing tool able to selectively etch gold from a Ti/Pt/Au triple metal layer. Attempts made by the usual I2/KI etch confirmed the damage that it causes to the crystal stack, and non-uniform attack of gold. A new etch, indicated as Epta-Methyl-bis-diodine, has been successfully employed. Careful time control and detailed characterization of the complex metallization pattern of the devices allowed not only to properly expose the Pt layer, but also to preserve the overall electrical connection, thus maintaining the capability of both measuring the electrical characteristics at low current injection and collecting the EBIC signal from the etched device.
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Kohandehghan, Alireza, Jonathan Prescott, Stuart Guest, and Sean Lepine. "An Engineering Assessment Methodology to Evaluate Arc Burns." In 2020 13th International Pipeline Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/ipc2020-9506.
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Abstract Arc burns, also known as arc strikes, are caused by momentary interaction of an electric arc, e.g., welding electrode or welding ground clamp, and a pipe or fitting, upon which a minimal or no amount of weld metal is deposited. Arc burns typically correspond with localized alteration of microstructures, shallow pitting, sharp surface contours, re-melting, and/or cracking. The damaged microstructures manifest in the form of a locally harder material due to accelerated cooling rates. Arc burns mainly form during the pipeline construction and are typically located adjacent to manually installed girth welds. The hard microstructures associated with arc burns are susceptible to hydrogen-induced cracking (HIC) in the presence of atomic hydrogen. Pipeline maintenance codes consider arc burns as defects and require their complete removal by grinding. Due to the relatively small dimension of arc burns, removal by grinding followed by etching contrast test is often the simplest and most reliable permanent repair for such defects. However, in some circumstances grinding to the maximum allowable depth may not completely remove the affected microstructures. Also, removal of arc burns often requires grinding near girth welds and significant grinding depths may require through-thickness inspection of the welds to ensure safety. Type B pressure containing steel sleeves are another permanent repair method that can be used to repair arc burns or partially removed arc burns within grinding metal loss features. Installation of permanent repairs over an arc burn is costly and may introduce additional or higher risks to the integrity of pipeline when scarce industry studies are available that conclusively demonstrate the dangers of leaving arc burns or partially removed arc burns in pipes. Despite the need, there is no validated engineering assessment method for the evaluation of arc burns. This paper will summarize an engineering assessment methodology and the findings of the evaluation of crack-free arc burns and partially removed arc burn features for two scenarios on vintage liquid pipelines. A combination of one- and three-dimensional finite element models was utilized to investigate the effect of arc burns and/or partially removed arc burns on the integrity of the pipeline based on plastic collapse, local yielding, and fatigue failure modes. The effect of the buried pipeline profile and soil was considered in the assessment of the axial load capacity of the pipeline. The geometrical and metallurgical stress concentrations of the features were considered in the engineering assessment. The engineering assessment determined if the pipeline with the arc burns and/or partially removed arc burns can survive rupture, brittle fracture, and fatigue damage mechanisms during its operation and if reinforcement of the area or cut-out is required.
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Panigrahi, Dillip Kumar, and Mihir Sarangi. "Fabrication of Deterministic Micro-Asperities on Thrust Surfaces Using Photo Chemical Machining." In ASME 2019 14th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/msec2019-2955.
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Abstract The present invention relates to characterization and the sequence of operations in photo chemical machining as a means to fabricate positive deterministic micro-textures on mild steel thrust pad surfaces. Fabrication of surface micro-texture by current technique is conceived in two-stages: where photographic emulsion process is used to pattern the microstructure, and chemical etching method is employed to fabricate the textures on mild steel surface by dissolving exposed metal surface. The texture fabricated by present invention is having slightly rough etched bottom surface with sharp edge and least amount of burrs around the texture rim and the process is also cost effective. Several aspects regarding sequence of operations in manufacturing process and the characterization of fabricated textured surfaces are discussed. The physical significance of micro-asperities on hydrodynamic lubrication is presented experimentally under constant flow system. The variation of hydrodynamic performance parameters such as frictional torque, fluid film thickness and recess pressure with different operating conditions such as varying speed and supply pressure are outlined.
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Korchnoy, Valentina. "Investigation of Bond-Pad Etching Chemistries for Determination of Probe/Bonding Related Sub-Pad Cracks." In ISTFA 2007. ASM International, 2007. http://dx.doi.org/10.31399/asm.cp.istfa2007p0206.
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Abstract Bond-pad integrity directly affects the performance of microelectronic devices. Bond-pad cracking and the related sub-pad cracking of Inter-Metal Dielectric (IMD) may introduce a high reliability risk and cause units to fail at environmental stress. Bond-pad cracks may be initiated by probing during wafer sort and the wire bonding process during assembly. This paper presents a comparative analysis of the various chemistries used for exposure and decoration of pad cracks. The investigation showed that a tri-iodine etch provides clean and artifact-free exposure of the TiN barrier layer of the pad and is the best (of the methods tried herein) for pad crack observation.
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Maiga, Abdoul Kader, and Adam Huang. "Swelling-Etching Characterization of PDMS-Copper Particle for the Development of the Nano/Micro-Particle Polymer Composite MEMS Corrosion Sensor." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-53705.
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The concept of using Micro-Electro-Mechanical Systems (MEMS) for in-situ corrosion sensing and for long-term applications has been proposed and is currently under development by our research lab. This is a new type of sensing using MEMS technology and, to the knowledge of our team, has not been explored previously. The MEMS corrosion sensor is based on the oxidation of metal nano/micro-particle embedded in elastomeric polymer to form a composite sensing element. The polymer controls the diffusion into and out of the sensor while the corrosion of the metal particles inhibits electrical conduction which is used as the detection signal. The work presented here is based on the experimental wet-chemistry method developed for the removal of native and process-induced metal oxides. A major aspect is the study of the swelling dynamics of the polymer matrix (polydimethylsiloxane, PDMS) and its influence on the material transport of etchants into and reaction products out of the composite during oxide removal. The understanding of this process is important to the ultimate development of the MEMS corrosion sensor, where the swelling must be controlled sufficiently to prevent stress-induced delamination of the sensing element from the substrate. For the first time, the simultaneous swelling (toluene) and oxide removal (acetic acid) characterization of the copper particles embedded in PDMS will be published. The experimental setup consists of small disk samples of the composite (6.35mm diameter × 1mm thick) dropped into a 50mL beaker filled with the swelling agent (the amount of which is part of the parametric study). This is then followed by the addition of the etching agent after reaching the swelling time constants characterized in prior work. The full process is captured through a HD webcam set inverted underneath the beaker. The swelling and contraction process is analyzed in real-time, while post processing of the recorded video is available to verify unexpected responses. Data gather so far indicate interesting swelling recovery phenomenon that is mostly consistent with the two part kinetics of swelling and etching. However, some data also seem to suggest a third mechanism that may be explained by material stiffness changes as etching and swelling proceed simultaneously. A full set of data currently being gathered will provide more clues and aid in the development of a consistent theoretical explanation. The final goal of this series of experiment is to provide mathematical models of the observed phenomenon so they can be used to aid the development of the fabrication processes of the MEMS corrosion sensor.
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Lee, Cheng-Chang, and Wensyang Hsu. "A New Surface Modification Method to Alleviate Stiction of Microstructures." In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-39299.
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Modification on surface roughness has been shown effectively to alleviate both release and in-use stiction in the previous literatures. However, the modified materials in the previously reported methods were limited to polysilicon or single crystalline silicon with special properties. Here, the proposed modification method not only can apply to silicon without extra property requirements, but also has potential to modify other materials, such as oxide, nitride, and some metals. The process combined spin-on photoresist and reactive ion etching (RIE). The proposed low temperature process is simple, and no extra mask is needed. Consequently, there is more flexibility to add the roughness modification to the original fabrication process of micro devices. In this study, polysilicon and silicon nitride are demonstrated as the modified materials. Then the anti-stiction effect is characterized by calibrating the detachment lengths of released cantilevers and water contact angle on the modified surface. The experimental results show that the detachment length is almost twice longer than the cantilevers without modified substrate, where the interfacial surface energy between solids is reduced about fifteen times. Besides, polysilicon with a nearly hydrophobic surface is obtained after the modification process.