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Oxidation Behaviour Of Mcralx Coatings
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Book Synopsis Oxidation behaviour of MCrAlX coatings by : Pimin Zhang
Download or read book Oxidation behaviour of MCrAlX coatings written by Pimin Zhang and published by Linköping University Electronic Press. This book was released on 2018-02-12 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: MCrAlY coatings (M=Ni and/or Co) have been widely used for the protection of superalloy components against oxidation and hot corrosion in the hot sections of gas turbines. The drive to improve engine combustion efficiency while reducing emissions by increasing the operation temperature brings a big challenge for coating design. As a result, the need for improvement of MCrAlY coatings for better oxidation resistance is essential. Formation of a stable, dense, continuous, and slow-growing ?-Al2O3 layer, on the MCrAlY coating surface, is the key to oxidation protection, since the protective ?-Al2O3 scale offers superior oxidation resistance due to its lower oxygen-diffusion rate as compared with other oxides. The ability of a MCrAlY coating to form and maintain such a protective scale depends on the coating composition and microstructure, and can be improved through optimization of deposition parameters, modification of coating surface conditions, and so on. Part of this thesis work focuses on studying the effect of post-deposition surface treatments on the oxidation behavior of MCrAlX coatings (X can be yttrium and/or other minor alloying elements). The aim is to gain fundamental understanding of alumina scale evolution during oxidation which is important for achieving improved oxidation resistance of MCrAlX coatings. Oxide scale formed on coatings at initial oxidation stage and the effect of surface treatment were investigated by a multi-approach study combining photo-stimulated luminescence, microstructural observation and weight gain. Results showed that both mechanically polished and shot-peened coatings exhibited superior performance due to rapid formation of ?-Al2O3 fully covering the coating and suppressing growth of transient alumina, assisted by the high density of ?-Al2O3 nuclei on surface treatment induced defects. The early development of a two-layer alumina scale, consisting of an inward-grown inner ?-Al2O3 layer and an outer layer transformed from outward-grown transient alumina, resulted in a higher oxide growth rate of the as-sprayed coating. The positive effect of the surface treatments on retarding oxide scale growth and suppressing formation of spinel was also observed in oxidation test up to 1000 hrs. As the oxidation proceeds to the close-to-end stage, a reliable criterion to estimate the capability of coating to form ?-Al2O3 is of great importance to accurately evaluate coating lifetime, which is the aim of the other part of the thesis work. Survey of published results on a number of binary Ni-Al and ternary Ni-Cr-Al, Ni-Al-Si systems shows that the empirical Al-concentration based criterion is inadequate to properly predict the formation of a continuous ?-Al2O3 scale. On the other hand, correlating the corresponding Al-activity data, calculated from measured chemical compositions using the Thermo-Calc software, to the experimental oxidation results has revealed a temperature dependent, critical Al-activity value for forming continuous ?-Al2O3 scale. To validate the criterion, long-term oxidation tests were performed on five MCrAlX coatings with varying compositions and the implementation of the Al-activity based criterion on these coatings successfully predicted ?-Al2O3 formation, showing a good agreement with experiment results.
Book Synopsis Performance of MCrAlX coatings by : Pimin Zhang
Download or read book Performance of MCrAlX coatings written by Pimin Zhang and published by Linköping University Electronic Press. This book was released on 2019-11-04 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: MCrAlY coatings (M=Ni and/or Co) are widely used for the protection of superalloy components against oxidation and hot corrosion in the hot sections of gas turbines. The drive for coating systems to bestow adequate oxidation and corrosion resistance upon the components becomes urgent as an inevitable result of the necessary improvement in engine combustion efficiency and service lifetime. Through the careful design of the composition, MCrAlY coating performance can be optimized to meet the needs under different service conditions and component materials, therefore, “MCrAlX”, with “X” stands for the minor alloying elements, is used to highlight the effect. In the present thesis, the performance of new MCrAlX coatings is investigated with respect to oxidation, hot corrosion and interactions between coating-superalloy substrates. Oxidation of MCrAlX coatings can be generally categorized into initial, steady and close-to-end stages. Coating performance can be affected by various factors at different stages, therefore, experiments were designed by targeting the oxidation stages. Investigation on the initial stage oxidation behavior of MCrAlY coatings with post-deposition surface treatments reveals the different growth mechanisms of alumina scales. Surface treatments significantly reduce the alumina growth rate by suppressing transient alumina development and aiding the early formation of ?-Al2O3, which improves the long-term oxidation performance of the coating. Similarly, the modification of minor alloy elements in MCrAlX coatings also serves the purpose. The oxidation behavior of new MCrAlX coatings was investigated at the steady oxidation stage, followed by the microstructure observation, thermodynamic and kinetic simulations. As an alternative reactive element addition of Y, Ce shows a negative effect on the formation of columnar alumina scales of high strain tolerance. In comparison, Fe or Ru addition shows no influence on alumina growth, rather than strengthening the phase stability in the coating and reducing the interdiffusion between coating-substrate through different mechanisms. As the oxidation proceeds to the close-to-end stage, a reliable criterion to estimate the capability of coating to form ?-Al2O3 is of great importance to accurately evaluate coating lifetime. A temperature-dependent critical Al-activity criterion was proposed to better predict the formation of a continuous ?-Al2O3 scale based on correction of elemental activity using thermodynamic database to replace the empirical Al-concentration based criterion. Severe interdiffusion occurs between coating-substrate during high temperature oxidation, accelerating the degradation of the system. Interdiffusion behavior of diffusion couples of superalloys-MCrAlX coatings were examined. It is highlighted that the recrystallization of superficial layer of the substrate contributes to the secondary reaction zone formation and element interdiffusion controls subsequent zone thickening. Study on Type I hot corrosion behavior of new MCrAlX coatings shows that the addition of Fe has no influence on basic fluxing reactions before severe Al depletion from the coating occurs. Instead, it boosts the “effective” Al supply of coating by shifting the equilibrium concentration of Al in the ? phase to a low Al level. Besides, the pre-mature coating degradation at the coating-substrate interface was due to the fast growth of corrosion products from substrate induced large local volume expansions, resulting in early coating spallation. MCrAlY ytbeläggningar (M=Ni och/eller Co) används ofta för att skydda komponenter tillverkade av superlegeringar mot oxidation samt högtemperaturskorrosion i de heta gasturbindelarna. Förbättrad förbränningseffektivitet och livslängd hos gasturbiner, gör att ytbeläggningssystemen måste besitta adekvata oxidations- och korrosionsmotstånd. Genom att omsorgsfullt utforma den kemiska sammansättningen hos MCrAlY ytbeläggningar kan deras prestanda optimeras för att möta kraven från olika driftförhållanden samt olika substratmaterial, därför används beteckningen "MCrAlX" för att belysa förändringar av den kemiska kompositionen, där "X" står för reaktiva legeringsämnen som tillsätts i mindre mängder. I denna avhandling undersöks prestandan hos en ny MCrAlX ytbeläggning med hänsyn till oxidation, högtemperaturskorrosion och interaktionen mellan ytbeläggningen och superlegeringssubstratet. Oxidation av MCrAlX ytbeläggningar kan generellt kategoriseras i tre faser; initiala, stabila och nära-slutet fasen. Ytbeläggningens prestanda kan påverkas av olika faktorer vid de olika faserna, därför utformades olika experiment för att undersöka de olika oxidationsfaserna. Undersökningen av den initiala fasen av oxidationsbeteendet hos MCrAlX ytbeläggningar som genomgått ytbehandlingar efter ytbeläggningsdeponeringen avslöjade olika tillväxtmekanismer hos aluminiumoxidskikten. Aluminiumoxidens tillväxthastighet reducerades signifikant av ytbehandlingarna, detta genom att undertrycka utvecklingen av övergående aluminiumoxid och bistå den tidiga tillväxten av ?-Al2O3, vilket förbättrar ytbeläggningens oxidationsprestanda långsiktigt. De reaktiva legeringsämnena som tillsätts i mindre mänger påverkar ytbeläggningens oxidationsprestanda på liknande sätt. Oxidationsbeteendet hos de nya MCrAlX ytbeläggningarna i den stabila fasen följdes av mikrostrukturundersökning, termodynamiska och kinetiska simuleringar. Det framkom att Ce visar en negativ effekt på bildandet av kolumnära aluminiumoxidskikt med hög töjningstolerans som alternativt reaktivt legeringsämne till Y. Jämförelsevis ger Fe- eller Ru-tillsatser ingen påverkan på aluminiumoxidtillväxten, förutom att det förstärker fasstabiliteten i ytbeläggningen samt genom olika mekanismer reducerar interdiffusionen mellan ytbeläggningen och substratet. När oxidationsprocessen kommit till nära-slutet fasen, är det viktigt att uppskatta kapaciteten hos en ytbeläggning att bilda ?-Al2O3, detta då det är ett tillförlitligt kriterium för att noggrant kunna utvärdera ytbeläggningens livslängd. Därför föreslogs ett temperaturberoende kriterium för kritisk Al-aktivitet för att bättre kunna förutsäga bildandet av ett kontinuerligt ?-Al2O3-skikt. Kriteriet baserades på korrigering av legeringsämnens aktivitet genom att använda en termodynamisk databas, detta för att ersätta det empiriska Al-koncentrations baserade kriteriet. Vid högtemperatursoxidation sker en omfattande interdiffusion mellan ytbeläggningen och substratet, vilket accelererar degraderingen av ytbeläggningssystemet. Därför har interdiffusionsbeteendet mellan superlegeringssubstratet och MCrAlX ytbeläggningen undersökts i denna avhandling. Det framkom att rekristallisationen av ytliga skikt av substratet bidrar till formationen av den sekundära reaktionszonen och att interdiffusion kontrollerar zonens efterföljande tjocklektillväxt. Undersökningen av Typ I högtemperaturskorrosionsbeteendet hos en ny MCrAlX ytbeläggning visar att legeringstillägg av Fe inte påverkar de grundläggande flödesreaktionerna innan en kritisk Al utarmning sker i ytbeläggningen. Istället stimulerar det tillförseln av Al genom att skifta jämviktskoncentrationen av Al i ? fasen till en låg nivå av Al. Det framkom också att den tidiga degraderingen av ytbeläggningen vid gränsskiktet mellan ytbeläggningen och substratet kommer av att den snabba tillväxten av korrosionsprodukter från substratet inducerade en stor lokal volymsutvidgning, vilket ledde till tidig ytbeläggningsspallation.
Book Synopsis Coatings for Harsh Environments by : Shiladitya Paul
Download or read book Coatings for Harsh Environments written by Shiladitya Paul and published by MDPI. This book was released on 2020-11-13 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: The operation of numerous components that are critical to safety in industries around the world relies on protective coatings. These coatings often allow process equipment to serve a purpose in environments well beyond the operational limit of the uncoated components. Durability, ease of application, repairability, reliability and long-term performance of such coatings are all key to their application. Therefore, this book, Coatings for Harsh Environments, is devoted to research and review articles on the metallic, non-metallic and composite coatings used in aggressive environments. In particular, the topics of interest include, but are not limited to: coatings for high temperature and molten salt applications; thermal spray and cold spray coatings for aggressive environments; corrosion, wear and cavitation resistant coatings; coatings for mitigating marine corrosion; coatings for chemical and petrochemical plants; thermal barrier coatings.
Book Synopsis Stereology and Image Analysis in Materials Science by : Agnieszka Szczotok
Download or read book Stereology and Image Analysis in Materials Science written by Agnieszka Szczotok and published by Trans Tech Publications Ltd. This book was released on 2013-02-27 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: The peer reviewed papers cover the latest research results on Stereology and Image Analysis in Materials Science. Volume is indexed by Thomson Reuters CPCI-S (WoS). The main topics are: applications in materials science and engineering, applications in biological materials, advances in microscopy, image processing and analysis, theoretical stereology and 3D modeling.
Author :National Research Council (U.S.). Committee on Coatings Publisher :National Academies ISBN 13 : Total Pages :246 pages Book Rating :4.:/5 (89 download)
Book Synopsis High-temperature Oxidation-resistant Coatings by : National Research Council (U.S.). Committee on Coatings
Download or read book High-temperature Oxidation-resistant Coatings written by National Research Council (U.S.). Committee on Coatings and published by National Academies. This book was released on 1970 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis High Temperature Coatings by : Sudhangshu Bose
Download or read book High Temperature Coatings written by Sudhangshu Bose and published by Butterworth-Heinemann. This book was released on 2017-11-27 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: High Temperature Coatings, Second Edition, demonstrates how to counteract the thermal effects of rapid corrosion and degradation of exposed materials and equipment that can occur under high operating temperatures. This is the first true practical guide on the use of thermally protective coatings for high-temperature applications, including the latest developments in materials used for protective coatings. It covers the make-up and behavior of such materials under thermal stress and the methods used for applying them to specific types of substrates, as well as invaluable advice on inspection and repair of existing thermal coatings. With his long experience in the aerospace gas turbine industry, the author has compiled the very latest in coating materials and coating technologies, as well as hard-to-find guidance on maintaining and repairing thermal coatings, including appropriate inspection protocols. The book is supplemented with the latest reference information and additional support to help readers find more application- and industry-type coatings specifications and uses. Offers an overview of the underlying fundamental concepts of thermally-protective coatings, including thermodynamics, energy kinetics, crystallography and equilibrium phases Covers essential chemistry and physics of underlying substrates, including steels, nickel-iron alloys, nickel-cobalt alloys and titanium alloys Provides detailed guidance on a wide variety of coating types, including those used against high temperature corrosion and oxidative degradation and thermal barrier coatings
Book Synopsis Progress in Thermal Barrier Coatings by : ACerS (American Ceramics Society, The)
Download or read book Progress in Thermal Barrier Coatings written by ACerS (American Ceramics Society, The) and published by John Wiley & Sons. This book was released on 2009-06-15 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: This edition of the Progress in Ceramic Technology series compiles articles published on thermal barrier coatings (TBCs) by The American Ceramic Society (ACerS). It collects in one resource the current research papers on materials-related aspects of thermal barrier coatings and associated technologies. Logically organized and carefully selected, the papers in this edition divide into six categories: Applications Material Improvements and Novel Compositions Developments in Processing Mechanical Properties Thermal Properties Citations follow each title in the table of contents, making this a key resource for professionals and academia.
Book Synopsis Advanced Ceramic Coatings and Interfaces by : Dongming Zhu
Download or read book Advanced Ceramic Coatings and Interfaces written by Dongming Zhu and published by John Wiley & Sons. This book was released on 2009-09-29 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent advances in coating development, processing, microstructure and property characterization, and life prediction are included in this book, which came from the proceedings of the 30th International Conference on Advanced Ceramics and Composites, January 22-27, 2006, Cocoa Beach, Florida. Organized and sponsored by The American Ceramic Society and The American Ceramic Society's Engineering Ceramics Division in conjunction with the Nuclear and Environmental Technology Division.. Integrated structural, environmental properties and functionality through advanced coating processing and structural design are emphasized in this book.
Book Synopsis Materials and Coatings to Resist High Temperature Corrosion by : Derek Roy Holmes
Download or read book Materials and Coatings to Resist High Temperature Corrosion written by Derek Roy Holmes and published by . This book was released on 1978 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Superalloys written by Roger C. Reed and published by Cambridge University Press. This book was released on 2008-07-31 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: Superalloys are unique high-temperature materials used in gas turbine engines, which display excellent resistance to mechanical and chemical degradation. This book introduces the metallurgical principles which have guided their development. Suitable for graduate students and researchers, it includes exercises and additional resources at www.cambridge.org/9780521859042.
Book Synopsis Aerospace Alloys by : Stefano Gialanella
Download or read book Aerospace Alloys written by Stefano Gialanella and published by Springer Nature. This book was released on 2019-10-30 with total page 583 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an up-to-date overview on the main classes of metallic materials currently used in aeronautical structures and propulsion engines and discusses other materials of potential interest for structural aerospace applications. The coverage encompasses light alloys such as aluminum-, magnesium-, and titanium-based alloys, including titanium aluminides; steels; superalloys; oxide dispersion strengthened alloys; refractory alloys; and related systems such as laminate composites. In each chapter, materials properties and relevant technological aspects, including processing, are presented. Individual chapters focus on coatings for gas turbine engines and hot corrosion of alloys and coatings. Readers will also find consideration of applications in aerospace-related fields. The book takes full account of the impact of energy saving and environmental issues on materials development, reflecting the major shifts that have occurred in the motivations guiding research efforts into the development of new materials systems. Aerospace Alloys will be a valuable reference for graduate students on materials science and engineering courses and will also provide useful information for engineers working in the aerospace, metallurgical, and energy production industries.
Book Synopsis Bibliography on the High Temperature Chemistry and Physics of Materials by :
Download or read book Bibliography on the High Temperature Chemistry and Physics of Materials written by and published by . This book was released on 1982 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Design of Thermal Barrier Coatings by : Mohit Gupta
Download or read book Design of Thermal Barrier Coatings written by Mohit Gupta and published by Springer. This book was released on 2015-05-05 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book details the relationships between microstructure, interface roughness, and properties of thermal barrier coatings. The author proposes a method for the reduction of the thermal conductivity of the ceramic layer in order to increase the lifetime of thermal barrier coatings. He includes models for the optimization of ceramic layer microstructure and interface roughness.
Download or read book Gas Turbines written by Gurrappa Injeti and published by BoD – Books on Demand. This book was released on 2015-02-25 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents current research in the area of gas turbines for different applications. It is a highly useful book providing a variety of topics ranging from basic understanding about the materials and coatings selection, designing and modeling of gas turbines to advanced technologies for their ever increasing efficiency, which is the need of the hour for modern gas turbine industries. The target audience for this book is material scientists, gas turbine engine design and maintenance engineers, manufacturers, mechanical engineers, undergraduate, post graduate students and academic researchers. The design and maintenance engineers in aerospace and gas turbine industry will benefit from the contents and discussions in this book.This book presents current research in the area of gas turbines for different applications. It is a highly useful book providing a variety of topics ranging from basic understanding about the materials and coatings selection, designing and modeling of gas turbines to advanced technologies for their ever increasing efficiency, which is the need of the hour for modern gas turbine industries. The target audience for this book is material scientists, gas turbine engine design and maintenance engineers, manufacturers, mechanical engineers, undergraduate, post graduate students and academic researchers. The design and maintenance engineers in aerospace and gas turbine industry will benefit from the contents and discussions in this book.
Book Synopsis Thermochemical properties of inorganic substances by : I. Barin
Download or read book Thermochemical properties of inorganic substances written by I. Barin and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 950 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the practical application of thermochemistry to the development and control of tech nical processes, the data for as many substances as possible are needed in conjunction with rapid and simple methods of calculating equilibrium constants, heat balances and the EMF of galvanic cells. For these three types of calculation the following three ther modynamic functions are suitable: The Planck function, the enthalpy and the Gibbs free energy, which are here defined and tabulated as unambigous functions of temperature for pure substances. The first edition of the tables was published in 1973 under the title "Thermochemical Properties of Inorganic Substances". The present supplementary volume contains the data and functions for a further 800 inorganic substances. In addition, the data for about 250 substances from the first volume have been up-dated. These usually small corrections produce better consistency with the data from more recent publications. The comments of users and reviewers of the first volume have largely been concerned with the difference between the present thermodynamic functions and the system used in the JANAF tables, the somewhat unconventional handling of heat balances adopted here, the notation of cell reactions, the description of non-stoichiometric phases and the accuracy of the tabulated data. To answer these questions and criticims the theore tical concepts and the practical use of the tables are dealt with in more detail in the introduction, following the recommendation of some reviewers.
Download or read book Materials Forum written by and published by . This book was released on 1986 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Mechanical Alloying And Milling by : Cury Suryanarayana
Download or read book Mechanical Alloying And Milling written by Cury Suryanarayana and published by CRC Press. This book was released on 2004-09-28 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book surveys the broad field of mechanical alloying from a scientific and technological perspective to form a timely and comprehensive resource valuable to both students and researchers. The treatment progresses from the historical background through a description of the process, the different metastable effects produced, and the mechanisms of
