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ISBN 13 :
Total Pages : 694 pages
Book Rating : 4.3/5 (129 download)
Download or read book Compte rendu written by and published by . This book was released on 1984 with total page 694 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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ISBN 13 :
Total Pages : 800 pages
Book Rating : 4.3/5 (91 download)
Download or read book Conference Papers Index written by and published by . This book was released on 1984 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt: Monthly. Papers presented at recent meeting held all over the world by scientific, technical, engineering and medical groups. Sources are meeting programs and abstract publications, as well as questionnaires. Arranged under 17 subject sections, 7 of direct interest to the life scientist. Full programs of meetings listed under sections. Entry gives citation number, paper title, name, mailing address, and any ordering number assigned. Quarterly and annual indexes to subjects, authors, and programs (not available in monthly issues).
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ISBN 13 :
Total Pages : 1354 pages
Book Rating : 4.3/5 (91 download)
Download or read book Physics Briefs written by and published by . This book was released on 1990 with total page 1354 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Sudhangshu Bose
Publisher : Butterworth-Heinemann
ISBN 13 : 0128047437
Total Pages : 418 pages
Book Rating : 4.1/5 (28 download)
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 418 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
Author : George Simkovich
Publisher : Springer Science & Business Media
ISBN 13 : 1461325196
Total Pages : 548 pages
Book Rating : 4.4/5 (613 download)
Download or read book Transport in Nonstoichiometric Compounds written by George Simkovich and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt: Prior to the 9th International Conference on Reactivity Solids in Krakow, Poland a group of about 25 international scientists held a special conference entitled "Transport in Nonstoichiometric Compounds" in late Aug. 1980 in Mogilany, Poland (near Krakow). This conference was well received in view of the interaction between the participants, as well as the resulting publication of the proceedings (Elsevier Scientific Publishing Company, 1982, edited by J. Nowotny). At this first conference the participants decided that it would be desirable to organize similar conferences at about two year intervals. Thus, a second meeting was held in late June, early July at Alenya, Pyrenees Orientales, France. This conference had a larger number of participants, about 50, but still managed to promote excellent interaction between all the participants. These proceedings, with editors G. Petot-Ervas, Hj. Matzke and C. Monty, have also been published by Elsevier as a special edition of the journal, Solid State lonics, Vol. 12 (1984). In view of the success of the initial two conferences, a third meeting was organized and held at The Pennsylvania State University, University Park, PA., 16802, U.S.A. from 11 June 84 to 15 June 84. The proceedings of this conference are presented in the following text.
Author : Gerry D. Moan
Publisher : ASTM International
ISBN 13 : 0803128959
Total Pages : 891 pages
Book Rating : 4.8/5 (31 download)
Download or read book Zirconium in the Nuclear Industry written by Gerry D. Moan and published by ASTM International. This book was released on 2002 with total page 891 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation The 41 papers of this proceedings volume were first presented at the 13th symposium on Zirconium in the Nuclear Industry held in Annecy, France in June of 2001. Many of the papers are devoted to material related issues, corrosion and hydriding behavior, in-reactor studies, and the behavior and properties of Zr alloys used in storing spent fuel. Some papers report on studies of second phase particles, irradiation creep and growth, and material performance during loss of coolant and reactivity initiated accidents. Annotation copyrighted by Book News, Inc., Portland, OR.
Author : Neil Birks
Publisher : Cambridge University Press
ISBN 13 : 9780521485173
Total Pages : 352 pages
Book Rating : 4.4/5 (851 download)
Download or read book Introduction to the High Temperature Oxidation of Metals written by Neil Birks and published by Cambridge University Press. This book was released on 2009-07-16 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: A straightforward treatment describing the oxidation processes of metals and alloys at elevated temperatures. This 2006 second edition retains the fundamental theory but incorporates advances made in understanding degradation phenomena. The first half provides an authoritative introduction to the basic principles, covering thermodynamics and mechanisms of high temperature corrosion of metals and alloys. The latter half extends the discussion to oxidation processes in complex systems, from reactions in mixed environments to protective techniques, including coatings and atmosphere control. The authors provide a logical and expert treatment of the subject, producing a revised edition that will be a comprehensive guide to material scientists and engineers requiring an understanding of this elementary process.
Author : Ludvig Landälv
Publisher : Linköping University Electronic Press
ISBN 13 : 9176850889
Total Pages : 42 pages
Book Rating : 4.1/5 (768 download)
Download or read book Physical vapor deposition and thermal stability of hard oxide coatings written by Ludvig Landälv and published by Linköping University Electronic Press. This book was released on 2019-04-26 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: The state-of-the-art tools for machining metals are primarily based on a metal-ceramic composite (WC-Co) coated with different combinations of carbide, nitride, and oxide coatings. Combinations of these coating materials are optimized to withstand specific wear conditions. Oxide coatings, mainly α-Al2O3, are especially desired because of their high hot-hardness, chemical inertness with respect to the workpiece, and their low friction. The search for possible alloy elements, which may facilitate the deposition of such oxides by means of physical vapor deposition (PVD) techniques, has been the goal of this thesis. The sought alloy should form thermodynamically stable or metastable compounds, compatible with the temperature of use in metal cutting application. This thesis deals with process development and coating characterization of such new oxide alloy thin films, focusing on the Al-V-O, Al-Cr-Si-O, and Cr-Zr-O systems. Alloying aluminum oxide with iso-valent vanadium is a candidate for forming the desired alloys. Therefore, coatings of (Al1-xVx)2O3, with x ranging from 0 to 1, were deposited with reactive sputter deposition. X-ray diffraction showed three different crystal structures depending on V-metal fraction in the coating: α-V2O3 rhombohedral structure for 100 at.% V, a defect spinel structure for the intermediate region, (63 - 42 at.% V), and a gamma-alumina-like solid solution at lower V-content, (18 and 7 at.%), were observed, the later was shifted to larger d-spacing compared to the pure γ-Al2O3 sample obtained if deposited with only Al-target. Annealing the Al-rich coatings in air resulted in formation of V2O5 crystals on the surface of the coating after annealing to 500 °C for 42 at.% V and 700 °C for 18 at.% V metal fraction respectively. The highest thermal stability was shown for pure γ-Al2O3-coating which transformed to α-Al2O3 after annealing to 1100° C. Highest hardness was observed for the Al-rich oxides, ~24 GPa. The hardness then decreases with increasing V-content, larger than 7 at.% V metal fraction. Doping the Al2O3 coating with 7 at.% V resulted in a significant surface smoothening compared to the binary oxide. The measured hardness after annealing in air decreased in conjunction with the onset of further oxidation of the coatings. This work increases the understanding of this complicated material system with respect to possible phases formed with pulsed DC magnetron sputtering deposition as well as their response to annealing in air. The inherent difficulties of depositing insulating oxide films with PVD, requiring a closed electrical circuit, makes the investigation of process stability an important part of this research. In this context, I investigated the influence of adding small amount of Si in Al-Cr cathode on the coating properties in a pulsed DC industrial cathodic arc system and the plasma characteristics, process parameters, and coating properties in a lab DC cathodic arc system. Si was chosen here due to a previous study showing improved erosion behavior of Al-Cr-Si over pure Al-Cr cathode without Si incorporation in the coating. The effect of Si in the Al-Cr cathode in the industrial cathodic arc system showed slight improvements on the cathode erosion but Si was found in all coatings where Si was added in the cathode. The Si addition promoted the formation of the B1-like metastable cubic oxide phase and the incorporation led to reduced or equal hardness values compared to the corresponding Si-free processes. The DC-arc plasma study on the same material system showed only small improvements in the cathode erosion and process stability (lower pressure and cathode voltage) when introducing 5 at.% Si in the Al70Cr30-cathode. The presence of volatile SiO species could be confirmed through plasma analysis, but the loss of Si through these species was negligible, since the coating composition matched the cathode composition also under these conditions. The positive effect of added Si on the process stability at the cathode surface, should be weighed against Si incorporation in the coating. This incorporation seems to lead to a reduction in mechanical properties in the as-deposited coatings and promote the formation of a B1-like cubic metastable oxide structure for the (Al,Cr)2O3 oxide. This formation may or may not be beneficial for the final application since literature indicates a slight stabilization of the metastable phase upon Si-incorporation, contrary to the effect of Cr, which stabilizes the α-phase. The thermal stability of alloys for metal cutting application is crucial for their use. Previous studies on another alloy system, Cr-Zr-O, had shown solid solution, for Cr-rich compositions in that material system, in the sought corundum structure. The thermal stability of α-Cr0.28Zr0.10O0.61 coating deposited by reactive radio frequency (RF)-magnetron sputtering at 500 °C was therefore investigated here after annealing in vacuum up to 870 °C. The annealed samples showed transformation of α-(Cr,Zr)2O3 and amorphous ZrOx-rich areas into tetragonal ZrO2 and bcc-Cr. The instability of the α-(Cr,Zr)2O3 is surprising and possibly related to the annealing being done under vacuum, facilitating the loss of oxygen. Further in situ synchrotron XRD annealing studies on the α-Cr0.28Zr0.10O0.61 coating in air and in vacuum showed increased stability for the air annealed sample up to at least 975 °C, accompanied with a slight increase in ex-situ measured nanohardness. The onset temperature for formation of tetragonal ZrO2 was similar to that for isothermally vacuum annealing. The synchrotron-vacuum annealed coating again decomposed into bcc-Cr and t-ZrO2, with an addition of monoclinic–ZrO2 due to grain growth. The stabilization of the room temperature metastable tetragonal ZrO2 phase, due to surface energy effects present with small grains sizes, may prove to be useful for metal cutting applications. The observed phase segregation of α-(Cr,Zr)2O3 and formation of tetragonal ZrO2 with corresponding increase in hardness for this pseudobinary oxide system also opens up design routes for pseudobinary oxides with tunable microstructural and mechanical properties.
Author : David John Young
Publisher : Elsevier
ISBN 13 : 008044587X
Total Pages : 593 pages
Book Rating : 4.0/5 (84 download)
Download or read book High Temperature Oxidation and Corrosion of Metals written by David John Young and published by Elsevier. This book was released on 2008-10-03 with total page 593 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is concerned with understanding the fundamental mechanisms of high temperature alloy oxidation. It uses this understanding to develop methods of predicting oxidation rates and the way they change with temperature, gas chemistry and alloy composition. The focus is on designing (or selecting) alloy compositions which provide optimal resistance to attack by corrosive gases. . Emphasises quantitative calculations for predicting reaction rates and the effects of temperature, oxidant activities and alloy compositions. . Uses phase diagrams and diffusion paths to analyse and interpret scale structures and internal precipitation distributions . Provides a detailed examination of corrosion in industrial gases (water vapour effects, carburisation and metal dusting, sulphidation) . Text is well supported by numerous micrographs, phase diagrams and tabulations of relevant thermodynamic and kinetic data . Combines physical chemistry and materials science methodologies.
Author : Werner Martienssen
Publisher : Springer Science & Business Media
ISBN 13 : 3540304371
Total Pages : 1143 pages
Book Rating : 4.5/5 (43 download)
Download or read book Springer Handbook of Condensed Matter and Materials Data written by Werner Martienssen and published by Springer Science & Business Media. This book was released on 2006-09-21 with total page 1143 pages. Available in PDF, EPUB and Kindle. Book excerpt: Springer Handbook of Condensed Matter and Materials Data provides a concise compilation of data and functional relationships from the fields of solid-state physics and materials in this 1200 page volume. The data, encapsulated in 914 tables and 1025 illustrations, have been selected and extracted primarily from the extensive high-quality data collection Landolt-Börnstein and also from other systematic data sources and recent publications of physical and technical property data. Many chapters are authored by Landolt-Börnstein editors, including the prominent Springer Handbook editors, W. Martienssen and H. Warlimont themselves. The Handbook is designed to be useful as a desktop reference for fast and easy retrieval of essential and reliable data in the lab or office. References to more extensive data sources are also provided in the book and by interlinking to the relevant sources on the enclosed CD-ROM. Physicists, chemists and engineers engaged in fields of solid-state sciences and materials technologies in research, development and application will appreciate the ready access to the key information coherently organized within this wide-ranging Handbook. From the reviews: "...this is the most complete compilation I have ever seen... When I received the book, I immediately searched for data I never found elsewhere..., and I found them rapidly... No doubt that this book will soon be in every library and on the desk of most solid state scientists and engineers. It will never be at rest." -Physicalia Magazine
Author : Jean Vereecken
Publisher : Springer
ISBN 13 :
Total Pages : 536 pages
Book Rating : 4.3/5 (91 download)
Download or read book EMC ’91: Non-Ferrous Metallurgy—Present and Future written by Jean Vereecken and published by Springer. This book was released on 1991 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: The programme covers all the different aspects of the metallurgy of non-ferrous metals from mining to fabricated products. Particular attention is paid to the European non-ferrous industry with respect to changes in demand, technology used, pressures on the environment and the competitive position of manufacturers.
Author : Franz Roters
Publisher : John Wiley & Sons
ISBN 13 : 3527642099
Total Pages : 188 pages
Book Rating : 4.5/5 (276 download)
Download or read book Crystal Plasticity Finite Element Methods written by Franz Roters and published by John Wiley & Sons. This book was released on 2011-08-04 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by the leading experts in computational materials science, this handy reference concisely reviews the most important aspects of plasticity modeling: constitutive laws, phase transformations, texture methods, continuum approaches and damage mechanisms. As a result, it provides the knowledge needed to avoid failures in critical systems udner mechanical load. With its various application examples to micro- and macrostructure mechanics, this is an invaluable resource for mechanical engineers as well as for researchers wanting to improve on this method and extend its outreach.
Author : Xiaolei Wu
Publisher : CRC Press
ISBN 13 : 100035332X
Total Pages : 796 pages
Book Rating : 4.0/5 (3 download)
Download or read book Heterostructured Materials written by Xiaolei Wu and published by CRC Press. This book was released on 2021-11-24 with total page 796 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heterostructured (HS) materials represent an emerging class of materials that are expected to become a major research field for the communities of materials, mechanics, and physics in the next couple of decades. One of the biggest advantages of HS materials is that they can be produced by large-scale industrial facilities and technologies and therefore can be commercialized without the scaling up and high-cost barriers that are often encountered by other advanced materials. This book collects recent papers on the progress in the field of HS materials, especially their fundamental physics. The papers are arranged in a sequence of chapters that will help new researchers entering the field to have a quick and comprehensive understanding of HS materials, including the fundamentals and recent progress in their processing, characterization, and properties.
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ISBN 13 :
Total Pages : 700 pages
Book Rating : 4.F/5 ( download)
Download or read book Zirconium in the Nuclear Industry written by and published by . This book was released on 1977 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Carl L. Yaws
Publisher : Gulf Professional Publishing
ISBN 13 :
Total Pages : 378 pages
Book Rating : 4.3/5 (91 download)
Download or read book Handbook of Thermodynamic Diagrams: Organic compounds C1 to C4 written by Carl L. Yaws and published by Gulf Professional Publishing. This book was released on 1996 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermodynamic property data are important in many engineering applications in the chemical processing and petroleum refining industries.
Author : Pimin Zhang
Publisher : Linköping University Electronic Press
ISBN 13 : 9176853810
Total Pages : 79 pages
Book Rating : 4.1/5 (768 download)
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 79 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.
Author : Pimin Zhang
Publisher : Linköping University Electronic Press
ISBN 13 : 9175190052
Total Pages : 80 pages
Book Rating : 4.1/5 (751 download)
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 80 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.
