Добірка наукової літератури з теми "Solid nickel's etching"

Electroless plating on Acrylonitrile Butadiene Styrene (ABS) is a metallization process that involves a reduction and oxidation reaction between the nickel source and the substrate material. The purpose of this research is to determine the ability of nickel deposition in the nickel electroless plating process with a specific etching time variation. This nickel electroless procedure begins with a chromic acid etching process that can last anywhere from 15 to 55 minutes and is useful for increasing roughness and creating submicroscopic cavities. After the etching process is finished, the surface roughness test is performed with a Mitutoyo SJ-210. Additionally, the activation step is carried out for 5 minutes in order for the polymer to become a conductor, allowing the plating process to proceed. The electroless plating process was then carried out for 55 and 75 minutes, with the goal of depositing nickel metal on the ABS surface. The coating results were analyzed using Fourier Transform Infrared (FTIR) spectroscopy IRSpirit/ATR-S serial No. A224158/Shimadzu to determine the functional groups formed both before and after the coating process, X-Ray Diffraction (XRD) to determine the character of the crystal structure, and phase analysis of a solid material using PANalytical type E'xpert Pro, To determine the surface morphology, the Zeiss EVO MA 10 was used to perform scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) at 1000x magnification. The test findings demonstrate that, based on a range of investigations, etching variations of 15,25,35,45, and 55 minutes etching time 55 minutes are the best nickel deposited substrates, as evidenced by EDS data, where this treatment has the largest weight fraction of nickel. As a result, the longer the etching period, the rougher the surface becomes, affecting the capacity of nickel deposition to increase. Furthermore, it can be demonstrated in this investigation that the nickel deposited is in an amorphous form.

In this work, the infiltration technique was used to produce hydrogen electrodes for solid oxide cells. Different infiltration methodologies were tested in order to try to shorten the infiltration cycle time. The porous scaffolds used for infiltration were based on highly porous yttria-stabilized zirconia (YSZ) obtained by etching the reduced nickel from the Ni-YSZ cermet in HNO3 acid. The support had a complex structure which included a ~130 µm porous functional layer with small pores and a ~320 µm thick supporting layer with large pores. Infiltrations have been carried out using aqueous nickel nitrate solutions. Various infiltration procedures were used, differing in temperature/time profiles. The results show that slow evaporation is crucial for obtaining a homogeneous material distribution leading to high-quality samples. A longer evaporation time promotes the proper distribution of nickel throughout the porous scaffold. The shortening of the heat treatment procedure leads to blockage of the pores and not-uniform nickel distribution.

A novel chemical process has been developed to formulate injectable nickel ink for conductive film. This chemical method has the ability to remove the oxidation on nickel nano-particle surfaces during ink fabrication; the nickel ions, which are produced during chemical etching, will be reduced and bridged among original nano-nickel particles in the following thermal sintering process at 350 °C. X-ray diffraction results exhibit that the final nickel film has no significant composition change by this chemical method and that oxidation has been effectively removed. Scanning electron microscopy images show that this chemical process reduces nickel oxides into nickel and that the reduced nickel sticks on the original nickel particle surface acting as a “bridge” connecting each particle. So solid diffusion can be triggered easily among bridged nickel particles and sintered at relatively low temperatures. The resistivity of printed film is to 5 × 10 − 6 Ω ∙m which is 71-times that of bulk nickel. The fabricated conductive nickel thin film has been applied on lithium ion batteries as a current collector for cathode and anode and shows good corrosion resistance and stability.

The formation of a silicon alloy has been achieved by electron beam irradiation of a nickel-silicon bilayer. This process, called SiDWEL1 , has been developed by Quantiscript. The nickel-silicon bilayer is very thin and the electron beam operates at low energy and current. Silicide formation occurred around the interaction volume of the electrons within the material. This paper describes the nature of the structures produced and the origin of the difficulties encountered with the characterization. The necessity of further analysis with TEM based techniques is highlighted.Figure 1 presents a cross-section of a typical sample. The growth of silicide grains is induced by the e-beam irradiation of the stack for few microseconds. Nucieation is initiated by the diffusion of silicon atoms in nickel grains, induced by the heating arising from the electron beam interaction with the solid. A new phase is revealed by FE-SEM observation, after wet etching of the nickel film, as shown in figures 2 and 3.

Downsized and complex micro-machining structures have to meet quality requirements concerning geometry and convince through increasing functionality. The development and use of cutting tools in the sub-millimeter range can meet these demands and contribute to the production of intelligent components in biomedical technology, optics or electronics. This article addresses the development of double-edged micro-cutters, which consist of a two-part system of cutter head and shaft. The cutting diameters are between 50 and 200 μm. The silicon carbide cutting heads are manufactured from the solid material using microsystem technology. The substrate used can be structured uniformly via photolithography, which means that 5200 homogeneous micro-milling heads can be produced simultaneously. This novel batch approach represents a contrast to conventionally manufactured micro-milling cutters. The imprint is taken by means of reactive ion etching using a mask made of electroplated nickel. Within this dry etching process, characteristic values such as the etch rate and flank angle of the structures are critical and will be compared in a parameter analysis. At optimal parameters, an anisotropy factor of 0.8 and an etching rate of 0.34 µm/min of the silicon carbide are generated. Finally, the milling heads are diced and joined. In the final machining tests, the functionality is investigated and any signs of wear are evaluated. A tool life of 1500 mm in various materials could be achieved. This and the milling quality achieved are in the range of conventional micro-milling cutters, which gives a positive outlook for further development.

This study aims to optimize the production conditions for forming graphene directly on a quartz substrate, using a carbon 60 (C60) thin film as a solid carbon source. In this experiment, we focused on the relationships between the thickness of the C60 film and the nickel (Ni) catalyst film and the heat treatment conditions. As the thicknesses of the C60 and Ni catalyst films increased, high-crystallinity multi-layered graphene was formed, however the optical transparency of the graphene film decreased. Scanning Electron Microscopy (SEM) observations and Raman scattering spectroscopy showed that after changing the atmosphere of the heat-treatment from an argon (Ar) gas to an Ar+ hydrogen (H2) gas, the optical transparency of the graphene film was remarkably improved, due to the migration and vaporization of the Ni film, and due to etching of the multi-layered graphene.

Silicon diodes, FETs, IGBTs still keep the majority of power device market, being much cheaper compared to SiC and GaN wide band gap-based devices. To keep the Si devices competitive, their manufacturing processes must be significantly improved. This includes forming Ohmic contacts. Currently the common process is PVD – physical vapor deposition of metal stacks. This process is not efficient: not selective and wasteful - metal sputtered or evaporated from target coats entire vacuum chamber, not just wafer being processed. Electroless deposition can be potentially used for metallization of Si power devices. The electroless process can be designed selective, so the metal deposits only on silicon surface, not on areas protected by dielectric films. The deposited layer must have good adhesion to silicon surface, make Ohmic contact, and preferably converts into silicide upon anneal. Nickel satisfies all these requirements, thus is a good candidate. A major issue in Nickel plating on Si is that it does not deposits well onto very smooth polished surface of Si. Several approaches are known how to overcome this issue. Dubin [1] suggested adding pretreatment with Palladium. The Pd reacts autocatalytically on silicon surface forming Pd islands. Upon switching to Ni bath, Ni deposits on Pd first, then forms a continuous film when the islands merge. One issue in the Pd/Ni process are that the native oxide on silicon must be removed so Pd can reach Si. In Dubin’ process this is resolved by adding HF to Pd bath. Another issue is bad process repeatability – a consequence of autocatalytic nature of the Pd plating reaction. The autocatalytic processes have uncontrollable “incubation” time, therefore repeating Pd plating with same recipe (same time) does not produce the same results. We describe a new approach as to plate Nickel directly on polished Silicon surface. In our process the Pd activation of Si surface is replaced by a stain etch process. The stain etch is a process where crystalline Silicon is converted into porous Si layer [2]. Technically the stain etch is simply processing in a wet bath – mixture of concentrated nitric and hydrofluoric acids in a ratio around 1:1000. Same as in the Pd/Ni case, the process must be designed to exclude native Si oxide. We achieve this by direct switching from the stain bath to Ni bath, no water rinsing in between. The surface of wafer retrieved from the stain bath is highly hydrophobic (hydrogen terminated) thus there is no liquid drops on surface. A brief nitrogen gun drying is still performed, thus preventing contamination of Ni bath with HF. The hydrogen termination protects the surface. We tried both traditional Ni plating recipes – alkaline, and acidic [3], and found that Ni plating is good in both cases. However, the resulting Ni layer is heavily non-uniform in thickness. We observe that the Ni pattern repeats the visual pattern after the stain etch. A byproduct of the stain etch reaction is hydrogen. The hydrogen forms bubbles that stick to Si surface and cause local masking, eventually non-uniformity. Thus, the key to Ni plating uniformity is the uniform stain etch. Known approaches [2] - adding surfactants to the bath, etc. happen to be only partially efficient. Therefore, we tried new stain etch recipe: add glacial acetic acid thus getting HNA mixture 1000:1:1000. The hydrogen bubbles in the old recipe were about 2 mm in diameter and kept on Si surface for many seconds. In our recipe, the bubbles get released from Si surface as soon as they reach about 0.1 mm size. The eventual Si porous layer shows uniform color appearance across entire wafers. Notice, etching in the nitric/hydrofluoric mixture is also autocatalytic process, thus the topic of repeatability arises too. However, we use Si surface color change as the signal to finish the stain etch. Thus, we can get the same thickness porous film every time despite the incubation time varies uncontrollably. Direct Ni plating onto blanket polished Silicon wafers with the HNA 1000:1:1000 pretreatment shows uniform mirror like appearance. Very high surface area of the porous Si enables the Ni plating. Nano scale sizes of porous Si with plated Ni result in uniform silicide upon anneal. References Dubin, V.M., "Selective electroless Ni deposition onto Pd-activated Si for integrated circuit fabrication" Thin Solid Films 226,no.1(1993):94-98. Kolasinski, K.W. "Porous Si formation by galvanic etching." Handbook of Porous Silicon2 (2014). Delaunois, F. Electroless nickel plating: fundamentals to applications. CRC Press, 2019.

This paper presents a model for producing nano-microparticles by ultrasound-aided electric discharge. After machining, scanning electron microscopy (SEM) was used to check the shape and size of the nickel particles; they were found to be distributed in a few micrometers to 80 [Formula: see text]m range. The nickel particles were regular spherical shaped, and the grain sizes of the particles were different. In addition, many small particles were attached to the surface. Various methods such as inlay polishing, nitric acid etching, and direct SEM imaging were employed to determine the hollow nickel particles such as very thin particles, large thickness grains, hollow sponge-like structures, and solid particles.

AbstractMiniature solid oxide fuel cells (μSOFC) are very promising energy sources for portable devices. In this work we report on fabrication and on first experimental results of μSOFCs processed by means of silicon and thin film technology. All the layers involved in the PEN (Positive electrode-Electrolyte-Negative electrode) structure were sputter deposited on silicon wafer. The PEN membrane was liberated using deep silicon dry etching. The cathode is a combination of a very fine platinum grid covered by a thin LSC layer. The electrolyte is a bilayer of YSZ and CGO ionic conductors. Scanning electrons microscope and X-ray analysis show that the deposited films are polycrystalline with a columnar microstructure. The conductivities of these films are sufficiently high for cell operation at 550°C. The anode is composed of a NiO-Ni-CGO composite. A supporting structure consisting of an electroplated nickel grid is deposited on top of the anode and is part of it. The final PEN is a free standing 1 micron thick membrane, with a diameter of 5 mm. First measurements showed that this structure is mechanically stable up to 550°C and that the cell works with an OCV of 200 mV.

La structuration à l’échelle submicronique de la surface des aciers inoxydables permet de leur apporter de nouvelles fonctionnalités, par exemple pour des applications tribologiques et optiques. Cette thèse s’inscrit dans le cadre du projet ANR SPOT qui a pour objectif de structurer à l’échelle submicronique la surface d’aciers austénitiques et martensitiques par gravure sèche. Dans ce travail, nous avons développé un procédé plasma avec un mélange de chlore et d’argon pour la gravure des aciers inoxydables. La mise au point de ce procédé a été réalisée en se basant sur l’étude de la gravure des métaux principaux qui composent ces aciers, à savoir, le fer, le chrome et le nickel. En se basant sur des mesures de vitesses de gravure, ainsi que sur des techniques de diagnostics plasmas, nous avons montré que, dans un plasma de chlore et d’argon, le fer est l’élément qui se grave le plus, suivi du chrome puis du nickel. Les échantillons métalliques ainsi que les aciers inoxydables gravés ont été analysés par des techniques de caractérisation de surface notamment des analyses de spectrométrie photoélectronique X (XPS). Nous avons également étudié la variation des vitesses de gravures de ces métaux et de ces aciers en fonction de la température des substrats. Ces études nous ont permis d’établir les mécanismes mis en jeu en cours de la gravure des éléments métalliques. Nous avons montré que, dans un plasma de chlore et d’argon, le fer se grave principalement par un mécanisme chimique qui suit une loi d’Arrhenius. Ce mécanisme serait basé sur la formation de chlorures de fer volatiles. Dans le cas du chrome, la gravure nécessite une assistance ionique afin de désorber les chlorures de chrome non volatiles formés à la surface du matériau. Enfin, pour le nickel, nous avons observé que la vitesse de gravure diminue lorsque la température augmente. Dans ce cas, des observations au microscope électronique à balayage ont permis de mettre en évidence la formation de gonflements riches en chlore. Les analyses XPS de la surface gravée du nickel suggère que ces gonflements sont dus à la formation de chlorures de nickel non volatiles. Ces chlorures seraient à l’origine de la diminution de la vitesse de gravure du nickel dont la pulvérisation se trouverait bloquée par la présence de ces chlorures. La compréhension de ces mécanismes a permis de conclure que, dans un plasma chloré, l’élément bloquant dans la gravure des aciers inoxydables est le nickel
The structuring at sub-micronic scale of the surface of stainless steels allows to provide them with new functionalities, for example for tribological and optical applications. This thesis is part of the ANR SPOT project which aims to structure the surface of austenitic and martensitic steels on a submicronic scale by dry etching. In this work, we have developed a plasma process with a mixture of chlorine and argon for the etching of stainless steels. The development of this process was carried out based on the study of the etching of the main metals that make up these steels, namely, iron, chromium and nickel. Based on measurements of etching speeds, as well as on plasma diagnostic techniques, we have shown that, in a chlorine and argon plasma, iron is the most etched element, followed by chromium, then nickel. The metallic and the stainless steels etched samples were analyzed by surface characterization techniques, in particular X photoelectron spectrometry (XPS) analyzes. We have also studied the variation of the etching speeds of these metals and steels as a function of the temperature of the substrates. These studies have enabled us to establish the mechanisms involved in the etching of metallic elements. We have shown that in a plasma of chlorine and argon, iron is mainly etched by a chemical mechanism which follows an Arrhenius law. This mechanism would be based on the formation of volatile iron chlorides. In the case of chromium, the etching requires ionic assistance in order to desorb the non-volatile chromium chlorides formed on the surface of the material. Finally, for nickel, we observed that the etching speed decreases when the temperature increases. In this case, observations with a scanning electron microscope made it possible to highlight the formation of swellings rich in chlorine. XPS analyzes of the etched surface of nickel suggest that these swellings are due to the formation of non-volatile nickel chlorides. These chlorides would be at the origin of the decrease in the rate of etching of nickel, the sputtering of which would be blocked by the presence of these chlorides. Understanding these mechanisms led to conclude that, in a chlorinated plasma, the blocking element in the etching of stainless steels is nickel

In this work, preparation of discontinuous nickel films on zirconium by electrochemical deposition of Ni-Cu alloy followed by selective anodic etching of the more noble metal, copper, was performed in an aqueous solution at room temperature. Potential varying electrodeposition produces were applied to obtain Ni-Cu alloys on Zr substrate. It is found that the Ni content increases as the deposition potential becomes more negative. Cyclic voltam-metric data indicate that the anodic dissolution of nickel is retarded by passivation. By taking the advantage of nickel passivation, selective anodic etching of Cu is achieved. Multicyclic electrochemical alloying/dealloying process makes the film rich of nickel and complete dealloying of copper.

Recently, our research group has proposed a MEMS-based solid state corrosion sensor, which is based on embedding metal particle into elastomeric polymers to form a composite-based sensing material. The chemical and dimensional properties of the metal particles and polymer matrix will provide the tailorability in sensor sensitivity, selectivity, time response, and operating life-span. However, the oxidization of metallic particles prior to embedding is adverse for electrical transduction of such sensor. This paper will be based on the investigation of chemical etching protocols used to remove the oxide coating from metal particles without adversely alter the particle itself. The etching process must also be compatible with common MEMS fabrication processes and not limited by the wide range of particle sizes used (30nm–100um). More specifically, metal particles such as Titanium, Aluminum, Nickel, and Stainless Steel are currently being used and investigated.

Abstract Friction stir processing (FSP) method is a solid-state technique used for microstructural alteration and enhancing mechanical properties of sheet metals and as-cast materials. Aluminium, brass, copper, steel, tin, nickel, magnesium and titanium are the widely used materials in friction stir processing. Even though magnesium has low density compared to aluminium, only few reports are made on magnesium. Two stage of process was carried out on the experiment to obtain fine grain refinement and improved strength. First, Cryo-rolling processing on 6mm thickness AZ31B alloy at constant roller power, roller rotation speed, strength coefficient and strain exponent. AZ31B alloy is dipped in liquid nitrogen for certain period and rolled in it’s cold state. Number of passes into roller was same for 9 samples. Cryo-rolled AZ31B is used as sample for the second stage i.e., Friction stir processing. FSPed material produce refined grain structure, micro-structurally modified cast alloys by alloying specific elements, and improvement in material strength. Based on Process parameters the properties of the material alters. Friction stir processing was performed on cryo-rolled AZ31B magnesium alloy with various processing parameters. The effect of process parameters (tool pin geometry, tool rotational speed and tool traverse speed) on two responses namely ultimate tensile strength and micro-hardness values were measured. The tool used for Friction stir processing is H13 high carbon steel with hardness upto 60 HRC. Tool pin geometry used for Friction stir processing are square, cylinder and tapered. The processed materials are cut using wire cut EDM as per ASTM standards to measure the ultimate tensile strength and hardness. Universal tester and Vickers hardness tester were used to measure the tensile strength and hardness of the Friction stir processed sample. Most of the research has been published on cryo-rolled and FSP experiments separately. In this work, a combination of these two process is developed for improved tensile strength, hardness, and ultrafine grain refinement. A multi-response optimization was performed using grey relation analysis (GRA) to find out the optimum combination of the process parameters for maximum ultimate tensile strength hardness. Analysis of variance (ANOVA) and F-test were performed to determine the most significant parameters at a 95% confidence level. The corrosion test was made on Friction stir processed cryo-rolled AZ31B alloy for every process parameters. Salt spray test was done as per ASTM standard to find the corrosion rate. The corrosion rate for Friction stir processed cryo-rolled material is less (at optimal condition). The microstructure analysis was done on the samples using a Scanning Electron Microscopy. For clear view of grains the material is subjected to polishing and etching. The etchant used on the material is Picral + Acetic acid + Hydrogen peroxide. Fine grain size was obtained on the Friction Stir processed Cryo-rolled AZ31B magnesium alloy at optimal condition.

Heatric has been involved in the commercial design and manufacturing of “micro/milli” scale heat exchanger core matrices called Printed Circuit Heat Exchangers (PCHEs) since 1985. These core matrices are formed by diffusion bonding together plates into which fluid flow microchannels have (usually) been formed by photo-chemical machining. Complex fluid circuitry is readily implemented with this technique. Diffusion bonding is a ‘solid-state joining’ process creating a bond of parent metal strength and ductility. The complete microchannel heat exchangers are highly compact, typically comprising about one-fifth the size and weight of conventional heat exchangers for the same thermal duty and pressure drops. PCHEs can be constructed out of a range of materials, including austenitic stainless steels suitable for design temperatures up to 800°C, and nickel alloys such as Incoloy 800HT suitable for design temperatures more than 900°C. Single units ranging from a few grams up to 100 tonnes have been manufactured. Currently there are thousands of tons of such microchannel matrix in hundreds of services — many of them arduous duties on offshore oil and gas platforms where the size and weight advantages of microchannel heat exchangers are of obvious benefit. Whilst these matrices are predominantly involved in thermally simple two-fluid heat exchange, albeit at pressures up to 500 bar, PCHEs have also been used for many multi-stream counter-flow heat exchangers. However the field of applications is very varied, including specialised chemicals processing, and PCHEs are even to be found orbiting the Earth in the International Space Station! Due to the inherent flexibility of the etching process, the basic construction may readily be applied to both a wider range, and more complex integration of process unit operations. Chemical reaction, rectification, stripping, mixing, and absorption, as well as boiling and condensation, can be incorporated into compact integrated process modules. Crucially, the resulting degree of compactness has led printed circuit technology to be the enabling technology in certain duties. Techniques for chemical coating onto the surfaces of channels continue to evolve, with applicability both to protective coatings and catalytically active coatings. We will describe a selection of innovative printed circuit technology examples. Alongside the more esoteric, Heatric is actively extending printed circuit technology to adapt to new market opportunities such as nuclear power generation plant and fuel cell systems. These applications perhaps represent two extremes of the both size and process integration, and thus aptly serve to demonstrate the range of industrial use of microchannel devices.