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On The Mechanism Of Niobium Electropolishing
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Book Synopsis The Mechanism of Electropolishing of Niobium in Hydrofluoric-Sulfuric Acid Electrolyte by :
Download or read book The Mechanism of Electropolishing of Niobium in Hydrofluoric-Sulfuric Acid Electrolyte written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Niobium surfaces are commonly electropolished in an effort to obtain optimal smoothness for high-field superconducting radio-frequency cavity applications. We report the use of controlled electrochemical analysis techniques to characterize electropolishing of Nb in a sulfuric and hydrofluoric acid electrolyte. Through the use of a reference electrode, we are able to clearly distinguish the anode and cathode polarization potentials as well as the electrolyte voltage drop, which together sum to the applied power supply voltage. We then identify the temperature and HF concentration dependence of each potential. We also report the use of electrochemical impedance spectroscopy (EIS) on this system. EIS results are consistent with the compact salt film mechanism for niobium electropolishing (EP) in this electrolyte and are not consistent with either the porous salt film or the absorbate-acceptor mechanism. Microscopic understanding of the basic Nb EP mechanism is expected to provide an appro.
Book Synopsis On the Mechanism of Niobium Electropolishing by : Ashwini Chandra
Download or read book On the Mechanism of Niobium Electropolishing written by Ashwini Chandra and published by . This book was released on 2012 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Pure Niobium is the material used to make Superconducting Radio Frequency (SRF) cavities. These cavities need to be free from surface defects like pits, bumps and protrusions to achieve the best performance. Electropolishing is commonly used as a final process to give a good surface finish to the niobium surface. The standard electrolyte used for electropolishing niobium is a 1:9 ratio of HF (48%) and H2SO4 (96%) respectively. The mechanism of electropolishing is not fully understood and also the best electropolishing parameters need to be determined. Acid concentration, stirring, temperature and amount of material removed are the parameters expected to affect the surface finish. Their effect is studied using electrochemical polarization measurement, galvanostatic and potentiostatic techniques. The electro-dissolution occurring needs to be under mass transport control for the phenomenon of electropolishing to occur. This is characterized by the presence of a current density plateau in the niobium polarization curves. However Galvanostatic experimental result analysis points to other interfering transport processes as well. Results based on microscopy, surface profile measurement and current transient measurements for different electrode configurations indicate the presence of natural convection as one of the reason which could be causing deviation from a perfect semi infinite linear diffusion model.
Book Synopsis NOVEL CHARACTERIZATION OF THE ELECTROPOLISHING OF NIOBIUM WITH SULFURIC AND HYDROFLUORIC ACID MIXTURES. by :
Download or read book NOVEL CHARACTERIZATION OF THE ELECTROPOLISHING OF NIOBIUM WITH SULFURIC AND HYDROFLUORIC ACID MIXTURES. written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Niobium surfaces are commonly electropolished in an effort to obtain optimally smooth surfaces for high-field SRF cavity applications. We report the first use of controlled electrochemical analysis techniques to characterize electropolishing of Nb in a sulfuric and hydrofluoric acid electrolyte. Through the use of a reference electrode we are able to clearly distinguish the anode, cathode polarization potentials as well as the electrolyte voltage drop that sum to the applied power supply voltage. We then separate the temperature and HF concentration dependence of each. We also report the first use of Electrochemical Impedance Spectroscopy (EIS) on this system. EIS results are consistent with a presence of a compact salt film at the Nb/electrolyte interface that is responsible for the limiting current. Microscopic understanding of the basic Nb EP mechanism is expected to provide an appropriate foundation with which to optimize the preparation of high-field niobium cavity surfaces. The implication of EIS for monitoring Nb surface during electropolishing shows this technology could be potentially used as a source of on-line feedback.
Book Synopsis Exploiting New Electrochemical Understanding of Niobium Electropolishing for Improved Performance of SRF Cavities for CEBAF. by :
Download or read book Exploiting New Electrochemical Understanding of Niobium Electropolishing for Improved Performance of SRF Cavities for CEBAF. written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent incorporation of analytic electrochemistry into the development of protocols for electropolishing niobium SRF cavities has yielded new insights for optimizing this process for consistent, high-performance results. Use of reference electrodes in the electrolyte, electrochemical impedance spectroscopy (EIS), rotating disk electrodes (RDE), and controlled sample temperatures has greatly clarified the process dynamics over the empirical understanding developed via years of practice. Minimizing RF losses at high operational gradients is very valuable for CW linacs. Jefferson Lab is applying these new insights to the low-loss 7-cell cavity design developed for the CEBAF 12 GeV Upgrade. Together with controlled cleaning and assembly techniques to guard against field-emission-causing particulates, the resulting process is yielding consistent cavity performance that exceeds project requirements. Cavity tests show BCS-limited Q well above 30 MV/m. Detailed process data, interpretation, and resulting rf performance data will be presented.
Book Synopsis Study on Electro-Polishing Process by Niobium-Plate Sample With Artificial Pits by :
Download or read book Study on Electro-Polishing Process by Niobium-Plate Sample With Artificial Pits written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Electro-polishing (EP) process is the best candidate of final surface-treatment for the production of ILC cavities. Nevertheless, the development of defects on the inner-surface of the Superconducting RF cavity during EP process has not been studied by experimental method. We made artificial pits on the surface of a Nb-plate sample and observed the development of the pit-shapes after each step of 30um-EP process where 120um was removed by EP in total. This article describes the results of this EP-test of Nb-sample with artificial pits.
Book Synopsis Electrochemical Engineering by : Richard C. Alkire
Download or read book Electrochemical Engineering written by Richard C. Alkire and published by John Wiley & Sons. This book was released on 2018-08-24 with total page 467 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume in the "Advances in Electrochemical Sciences and Engineering" series focuses on problem-solving, illustrating how to translate basic science into engineering solutions. The book's concept is to bring together engineering solutions across the range of nano-bio-photo-micro applications, with each chapter co-authored by an academic and an industrial expert whose collaboration led to reusable methods that are relevant beyond their initial use. Examples of experimental and/or computational methods are used throughout to facilitate the task of moving atomistic-scale discoveries and understanding toward well-engineered products and processes based on electrochemical phenomena.
Book Synopsis Annealing to Mitigate Pitting in Electropolished Niobium Coupons and SRF Cavities by :
Download or read book Annealing to Mitigate Pitting in Electropolished Niobium Coupons and SRF Cavities written by and published by . This book was released on 2011 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ongoing studies at Fermilab investigate whether dislocations and other factors instigate pitting during cavity electropolishing (EP), despite careful processing controls and the inherent leveling mechanism of EP itself. Here, cold-worked niobium coupons, which exhibited increased tendencies for pitting in our past study, were annealed in a high vacuum furnace and subsequently processed by EP. Laser confocal scanning microscopy and special defect counting algorithms were used to assess the population of pits formed. Hardness measurements indicated that annealing for 2 hours at 800 C produced recovery, whereas annealing for 12 hours at 600 C did not, as is consistent with known changes for cavities annealed in a similar way. The 800 C anneal was effective in some cases but not others, and we discuss reasons why tendencies for pitting remain. We discuss implications for cavities and continued work to understand pitting.
Book Synopsis Plasma Electrolytic Oxidation (PEO) Coatings by : Marta Mohedano
Download or read book Plasma Electrolytic Oxidation (PEO) Coatings written by Marta Mohedano and published by MDPI. This book was released on 2021-06-02 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma electrolytic oxidation (PEO), also known as micro-arc oxidation (MAO), functionalizes surfaces, improving the mechanical, thermal, and corrosion performance of metallic substrates, along with other tailored properties (e.g., biocompatibility, catalysis, antibacterial response, self-lubrication, etc.). The extensive field of applications of this technique ranges from structural components, in particular, in the transport sector, to more advanced fields, such as bioengineering. The present Special Issue covers the latest advances in PEO‐coated light alloys for structural (Al, Mg) and biomedical applications (Ti, Mg), with 10 research papers and 1 review from leading research groups around the world.
Book Synopsis Research and Development for Electropolishing of Nb for ILC Accelerator Cavities by :
Download or read book Research and Development for Electropolishing of Nb for ILC Accelerator Cavities written by and published by . This book was released on 2009 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of this project are to 1, Expand the scientific and technological understanding of the effect of post-treatment (electropolish, buffered chemical polish, low-temperature baking) on the surface of niobium; 2, Relate the knowledge to the performance of niobium superconducting radiofrequency accelerator cavities; and, 3, Thereby design and demonstrate an electropolish process that can be applied to complete cavities.
Book Synopsis Buffered Electropolishing - A New Way for Achieving Extremely Smooth Surface Finish on Nb SRF Cavities to be Used in Particle Accelerators by :
Download or read book Buffered Electropolishing - A New Way for Achieving Extremely Smooth Surface Finish on Nb SRF Cavities to be Used in Particle Accelerators written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Future accelerators require unprecedented cavity performance, which is strongly influenced by interior surface nano-smoothness. Electropolishing (EP) is the technique of choice to be developed for high-field superconducting radio frequency (SRF) cavities. Electrochemical impedance spectroscopy (EIS) and related techniques point to the electropolishing mechanism of Nb in a sulphuric and hydrofluoric acid electrolyte controlled by a compact surface salt film under F- diffusion-limited mass transport control. These and other findings are guiding a systematic characterization to form the basis for cavities process optimization.
Book Synopsis Electropolishing Niobium by : Pelleg, Joshua
Download or read book Electropolishing Niobium written by Pelleg, Joshua and published by National Research Council Canada. This book was released on 1966 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Basic Electropolishing Process Research and Development in Support of Improved Reliable Performance SRF Cavities for the Future Accelerator by :
Download or read book Basic Electropolishing Process Research and Development in Support of Improved Reliable Performance SRF Cavities for the Future Accelerator written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Future accelerators require unprecedented cavity performance, which is strongly influenced by interior surface nanosmoothness. Electropolishing is the technique of choice to be developed for high-field superconducting radiofrequency cavities. Electrochemical impedance spectroscopy (EIS) and related techniques point to the electropolishing mechanism of Nb in a sulfuric and hydrofluoric acid electrolyte of controlled by a compact surface salt film under F- diffusion-limited mass transport control. These and other findings are currently guiding a systematic characterization to form the basis for cavity process optimization, such as flowrate, electrolyte composition and temperature. This integrated analysis is expected to provide optimum EP parameter sets for a controlled, reproducible and uniform surface leveling for Nb SRF cavities.
Book Synopsis Effect of Surface Flow on Topography in Niobium Electropolishing by :
Download or read book Effect of Surface Flow on Topography in Niobium Electropolishing written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Electropolishing (EP) is reliably delivering improved performance of multi-celled niobium SRF accelerator cavities, attributed to the smoother surface obtained. This superior leveling is a consequence of an etchant concentration gradient layer that arises in the HF-H2SO4 electrolyte adjacent to the niobium surface during polishing. Electrolyte circulation raises the prospect that fluid flow adjacent to the surface might affect the diffusion layer and impair EP performance. In this study, preliminary bench-top experiments with a moving electrode apparatus were conducted. We find that flow conditions approximating cavity EP show no effects attributable to depletion layer disruption.
Book Synopsis Issues in Specialized Chemical and Chemistry Topics: 2013 Edition by :
Download or read book Issues in Specialized Chemical and Chemistry Topics: 2013 Edition written by and published by ScholarlyEditions. This book was released on 2013-05-01 with total page 1230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Issues in Specialized Chemical and Chemistry Topics: 2013 Edition is a ScholarlyEditions™ book that delivers timely, authoritative, and comprehensive information about Magnetic Resonance. The editors have built Issues in Specialized Chemical and Chemistry Topics: 2013 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Magnetic Resonance in this book to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Issues in Specialized Chemical and Chemistry Topics: 2013 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976 with total page 680 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Electrodissolution Processes by : Madhav Datta
Download or read book Electrodissolution Processes written by Madhav Datta and published by CRC Press. This book was released on 2020-12-09 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electrodissolution Processes: Fundamentals and Applications discusses the basic principles involved in high-rate anodic dissolution processes and their application in advanced machining, micromachining, and finishing operations. The fundamentals section of the book discusses the anodic dissolution behavior of different classes of metals and the influence of mass transport, current distribution, and surface film properties on the metal removal rate and surface finishing. The applications section of the book presents essential elements of electrochemical and assisted techniques for precision machining, micromachining, and polishing of advanced materials, including hard-to-machine conducting ceramic materials. Features A first-of-its-kind book that provides updated scientific and engineering information related to high-rate anodic dissolution processes Highlights the importance of the understanding of basic principles required for designing and optimizing ECM/EMM/EP processes Gives equal emphasis to the fundamentals and applications of electrodissolution processes Discusses the high-rate anodic dissolution of two broad classes of materials, namely, engineering and refractory materials Presents case studies to demonstrate the capabilities of different electrochemical and assisted machining, micromachining, and finishing operations Presents a dedicated chapter on electrochemical planarization of copper interconnects Madhav Datta is the Chairman of Amrita Center for Industrial Research and Innovation and a Distinguished Professor in the Department of Chemical Engineering and Materials Science, Amrita University, Coimbatore, India.
Book Synopsis Impact of Forming, Welding, and Electropolishing on Pitting and the Surface Finish of SRF Cavity Niobium by :
Download or read book Impact of Forming, Welding, and Electropolishing on Pitting and the Surface Finish of SRF Cavity Niobium written by and published by . This book was released on 2010 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: A broad range of coupon electropolishing experiments are described to ascertain the mechanism(s) by which large defects are formed near superconducting radiofrequency (SRF) cavity welds. Cold-worked vs. annealed metal, the presence of a weld, and several variations of electropolishing (EP) parameters were considered. Pitting is strongly promoted by cold work and agitation of the EP solution. Welding also promotes pitting, but less so compared with the other factors above. Temperature increase during EP did not strongly affect glossiness or pitting, but the reduced viscosity made the electrolyte more susceptible to agitation. The experiments suggest that several factors that are rather benign alone are combined by the cavity forming, welding, and processing sequence to promote the formation of defects such as pits. Process changes to mitigate these risks are discussed.
