Download or read book Synthesis and Analysis of Mo Si B Based Coatings for High Temperature Oxidation Protection of Ceramic Materials written by and published by . This book was released on 2015 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of Ni-based superalloys in turbine engines has all but been exhausted, with operating temperatures nearing the melting point of these materials. The use of ceramics in turbine engines, particularly ceramic matrix composites such as SiC/C and SiC/SiC, is of interest due to their low density and attractive mechanical properties at elevated temperatures. The same materials are also in consideration for leading edges on hypersonic vehicles. However, SiC-based composites degrade in high temperature environments with low partial pressures of oxygen due to active oxidation, as well as high temperature environments containing water or sand. The need for a protective external coating for SiC-based composites in service is obvious. To date, no coating investigated for SiC/C or SiC/SiC has been proven to be resistant to oxidation and corrosion at intermediate and high temperatures, as well as in environments deficient in oxygen. The Mo-Si-B coating shows great promise in this area, having been proven resistant to attack from oxidation at extreme temperatures, from water vapor and from calcia-magnesia-aluminosilicate (CMAS). The adaptation of the Mo-Si-B coating for ceramic materials is presented in detail here. Evaluation of the coating under a range of oxidation conditions as well as simulated re-entry conditions confirms the efficacy of the Mo-Si-B based coating as protection from catastrophic failure. The key to the oxidation and corrosion resistance is a robust external aluminoborosilica glass layer that forms and flows quickly to cover the substrate, even under the extreme simulated re-entry conditions. Suppression of active oxidation of SiC, which may occur during atmospheric re-entry and hypersonic flight trajectories, has also been examined. In order to adapt the Mo-Si-B based coating to low partial pressures of oxygen and elevated temperatures, controlled amounts of Al were added to the Mo-Si-B based coating. The resulting coating decreased the inward diffusion of oxygen with an external Al2O3 layer and effectively reduced the activity of Si in the underlying glass. Thus, the Mo-Si-B based coating is established as a viable protective coating for oxidation and corrosion protection for next-generation aerospace and aeronautical materials.

Download or read book Development of a Mo Si B Coating for Nb based Alloys and the Effects of Zr Additions to Mo Si B Coatings for Enhanced Oxidation Protection in Ultra high Temperature Applications written by and published by . This book was released on 2015 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: Higher efficiencies and reduced emissions performance of fossil fuel energy systems are achieved with increasing operation temperatures. This increase in operating temperature requires the use of materials with higher melting points such as refractory metal alloys. However, refractory metals suffer from catastrophic oxidation in this type of environment. Thus, oxidation protection for refractory metal alloys is a crucial step in developing next generation ultra-high temperature materials. To meet this challenge, an oxidation resistant coating for Nb based alloys has been designed as well as the incorporation of zirconium into the Mo-Si-B coating to provide further corrosion protection and a reduction in temperature for the underlying multi-layered structure. Niobium samples coated with a Mo-Si-B coating demonstrate enhanced oxidation protection compared to samples only coated with Si-B. Thermogravimetric analysis testing at 1300°C for 24 hours for both the Mo-Si-B coated Nb and Nb-based alloys show enhanced oxidation protection with mass changes of 0.44 mg/cm^2 and 0.55 mg/cm^2, respectively, compared to the uncoated alloy that had a mass change of 87.6 mg/cm^2. To demonstrate the design concept for a coating with thermal barrier behavior, Zr is added to the Mo-Si-B coating through the pack cementation technique. The resulting coating shows that the Zr reacts with the aluminosilica top layer to form Zr silicides and ZrO2. Upon oxidation, the coating forms a mixed top layer composed of borosilica, ZrO2 and ZrSiO4. Oxidation testing of the Zr modified Mo-Si-B coating exhibits low mass change indicating that the coating provides oxidation protection and that the Zr additions do not interfere with the oxidation protection of the Mo-Si-B coating. Finite element modeling using object oriented finite element analysis of the coating structures yielded an evaluation of the mechanical and thermal properties of the coatings, providing insight into the thermal performance and mechanical compatibility of the coating structures. Furthermore, simulations of the residual stresses of the Mo-Si-B based coatings suggest that they can withstand the thermal shock associated with high temperature applications. These results demonstrate that the Mo-Si-B based coating can enable the use of Nb and Nb-based alloys at temperature up to 1300°C in an oxidizing environment.

Download or read book Development of a Mo Si B Coating for Nb based Alloys and the Effects of Zr Additions to Mo Si B Coatings for Enhanced Oxidation Protection in Ultra high Temperature Applications written by Otto John Lu-Steffes and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Higher efficiencies and reduced emissions performance of fossil fuel energy systems are achieved with increasing operation temperatures. This increase in operating temperature requires the use of materials with higher melting points such as refractory metal alloys. However, refractory metals suffer from catastrophic oxidation in this type of environment. Thus, oxidation protection for refractory metal alloys is a crucial step in developing next generation ultra-high temperature materials. To meet this challenge, an oxidation resistant coating for Nb based alloys has been designed as well as the incorporation of zirconium into the Mo-Si-B coating to provide further corrosion protection and a reduction in temperature for the underlying multi-layered structure. Niobium samples coated with a Mo-Si-B coating demonstrate enhanced oxidation protection compared to samples only coated with Si-B. Thermogravimetric analysis testing at 1300°C for 24 hours for both the Mo-Si-B coated Nb and Nb-based alloys show enhanced oxidation protection with mass changes of 0.44 mg/cm^2 and 0.55 mg/cm^2, respectively, compared to the uncoated alloy that had a mass change of 87.6 mg/cm^2. To demonstrate the design concept for a coating with thermal barrier behavior, Zr is added to the Mo-Si-B coating through the pack cementation technique. The resulting coating shows that the Zr reacts with the aluminosilica top layer to form Zr silicides and ZrO2. Upon oxidation, the coating forms a mixed top layer composed of borosilica, ZrO2 and ZrSiO4. Oxidation testing of the Zr modified Mo-Si-B coating exhibits low mass change indicating that the coating provides oxidation protection and that the Zr additions do not interfere with the oxidation protection of the Mo-Si-B coating. Finite element modeling using object oriented finite element analysis of the coating structures yielded an evaluation of the mechanical and thermal properties of the coatings, providing insight into the thermal performance and mechanical compatibility of the coating structures. Furthermore, simulations of the residual stresses of the Mo-Si-B based coatings suggest that they can withstand the thermal shock associated with high temperature applications. These results demonstrate that the Mo-Si-B based coating can enable the use of Nb and Nb-based alloys at temperature up to 1300°C in an oxidizing environment.

Download or read book Pack Cementation of AI Additions Into Mo Si B based Coatings for Improved Resistance to High Temperature Water Vapor Attack written by Travis Alan Sossaman and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current Ni-based superalloys used in turbine power generation application have reached their limit of operation, and alternative high temperature materials are necessary to drive further improvements in combustion temperatures and efficiency. A variety of alternatives including ceramic composites and refractory materials are being considered, and among the most promising are the alloys and coatings of the Mo-Si-B system. The Mo-Si-B system alloys offer excellent high temperature strength and sufficient creep resistance along with the ability to resist oxidation through the development of a protective borosilica layer. These alloys generate the glass sacrificially during the transient stage through the production of amorphous SiO2 and B2O3 at the expense of MoO3(g), which is volatile above 800 °C, until full coverage of the alloy and steady state oxidation is achieved. Mo-Si-B based coatings further extend protection from oxidation via pre-existing oxide layer which reduces or eliminates material loss during the transient stage of oxidation by generating borosilica through solid-state transformation of MoSi2, MoB, Mo5Si3, Mo5SiB2, and Mo3Si silicides and borides. Such coatings possess resistance to ambient oxidation above 1600 °C and extreme environmental conditions such as hot corrosion, attack by CMAS, and SiO(g) volatilization in low pO2 environments. High temperature water vapor has been shown to attack silica-based protective systems through the generation of volatile silicon- and boron-hydroxides. Based on lifetime estimates, exposure of the base Mo-Si-B coating to high temperature water vapor indicated excellent resistance at 1300 °C, but accelerated oxidation at 1450 °C resulting in lifetime estimates below the target 10,000 hours. Alumina has been shown to be highly resistant to hydroxide formation below 1670 °C; therefore, incorporation of Al in the coating was explored for further improvements in water vapor resistance. The exploration of Al incorporation into Mo-Si-B coatings through co- and tri-pack cementation of Al, Si, and/or B as well as pack cementations done is series featuring a Si-B co-pack followed by Al or Al2O3 is detailed in this work. Pack cementation and diffusion couple data of relevant phases elucidated the mechanisms through which Al is incorporated into the coating and explores the kinetics of these processes. It was shown that the diffusivity of Al is greater than that of Si and B and must be controlled to retain desirable diffusion pathways and resulting coating structures. Further analysis has demonstrated a method for controlling the ratios of Al, Si, and B within the pack via adjusting the ratios of each element in the master alloy by comparing the ratio of expected equilibrium partial pressures of relevant halides and vapor phase components. Through this analysis, it was shown that both Si and B may be tuned via the relative amounts of SiF2(g) and BF(g) halides, while Al was most accurately controlled by the presence of Al(g). Through proper control of master alloy composition, temperature, and pack exposure time, Al incorporation may be optimized.

Download or read book Report on Coatings for Protecting Molybdenum from Oxidation at Elevated Temperature written by E. S. Bartlett and published by . This book was released on 1959 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ceramic Coatings for High Temperature Environments written by Amirhossein Pakseresht and published by Springer Nature. This book was released on 2024-01-06 with total page 493 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses the recent trends in thermal and environmental barrier coatings and their applications in extreme environments. It introduces the state of the art in coating materials and processes for high and ultrahigh-temperature environments and identifies areas for improvement in materials selection, performance upgrades, design considerations, and manufacturing methods. This book also covers fundamental studies involving modelling, creating coating architectures, coating preparation methods, and coating capability throughout a wide temperature range. The book examines a variety of high-temperature coatings prepared through various synthesis processes such as thermal spraying, electron beam evaporation, and sol–gel methods. This book also covers ultrahigh-temperature ceramic (UHTC) materials and provides a brief overview of the synthesis method, densification processes, and coating methods along with the properties and applications of emerging high entropy UHTCs. With contributions from international researchers active in the field, this edited book features the most recent and up-to-date literature references for a broad readership consisting of academic and industrial professionals. It is suitable for graduate students as well as materials scientists and engineers working in the area of high and ultrahigh-temperature ceramic materials.

Download or read book Coatings for High Temperature Environments written by Amirhossein Pakseresht and published by Springer Nature. This book was released on 2023-12-05 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses the recent trends in high-temperature coatings that are used to provide oxidation and wear resistance to metallic/ceramic components in extreme environments. Ceramics, intermetallics, organosilicon polymers, cermets, and other materials with great thermal stability have long been recognized for these applications. This book introduces the state of the art in coating materials and processes for high-temperature environments and identifies areas for improvement in materials selection, performance upgrades, design considerations, and manufacturing methods. The book covers a variety of high-temperature coatings prepared through various synthesis processes such as thermal spraying, physical vapor deposition, electrodeposition, and sol–gel methods. It covers corrosion/oxidation, phase stability, and thermal and mechanical behavior of high-temperature coating materials having greater thermal stability. With contributions from international researchers active in the field, this edited book features the most recent and up-to-date literature references for a broad readership consisting of academic and industrial professionals. It is suitable for graduate students as well as scientists and engineers working in the area of anti-corrosion and anti-wear resistant high-temperature coatings for industrial applications.

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 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of High temperature Oxidation Resistance Mechanism of Ceramic Coatings Via Microstructure Analysis written by Yi Shen (Ph.D.) and published by . This book was released on 2020 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent developments of ceramic coatings deposited using magnetron reactive sputtering show that these films exhibited superior high-temperature oxidation resistance along with other desirable properties such as high hardness, optical transparency and good electrical conductivity. Detailed microstructure study of these films annealed to high temperatures using transmission electron microscopy (TEM) is deemed necessary as it provides an intuitive vision on the behavior of the materials at elevated temperature, which is essential to further improve their high-temperature oxidation resistance. In this study, Hf-B-Si-C-N films with various compositions that were annealed to various temperatures in both helium and air were subjected to detailed TEM study. The results showed that while as-deposited films exhibited amorphous structure, annealing in air resulted in the formation of an oxide layer on top and the original film underneath. Meanwhile, annealing in helium led to partial recrystallization of the film into a nanocrystalline composite structure without oxidation. It was also observed that the addition of nitrogen helped the amorphization of the film at high temperatures and could potentially improve the oxidation resistance. Further improved design of the Hf-B-Si-C-N films can be accomplished with the addition of rare earth elements including yttrium and holmium, as well as tuning of silicon and boron content. The effects of these changes were also subjected to TEM microstructure analysis, in an effort to uncover the high temperature oxidation resistance mechanism. It is concluded that Hf6B21Si19C4N47 film, which exhibited superior thermal stability at high temperatures, had a relatively smooth and defect-4 free interface between the oxide layer and bottom layer, which in turn offer the best oxidation resistance among the films we have studied.

Download or read book MAX Phases and Ultra High Temperature Ceramics for Extreme Environments written by Low, I. M. and published by IGI Global. This book was released on 2013-05-31 with total page 679 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ceramics are a versatile material, more so than is widely known. They are thermal resistant, poor electrical conductors, insulators against nuclear radiation, and not easily damaged, making ceramics a key component in many industrial processes. MAX Phases and Ultra-High Temperature Ceramics for Extreme Environments investigates a new class of ultra-durable ceramic materials, which exhibit characteristics of both ceramics and metals. Readers will explore recent advances in the manufacturing of ceramic materials that improve their durability and other physical properties, enhancing their overall usability and cost-effectiveness. This book will be of primary use to researchers, academics, and practitioners in chemical, mechanical, and electrical engineering. This book is part of the Research Essentials collection.

Download or read book Ceramic Abstracts written by and published by . This book was released on 2000 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of Microstructure Effects on Hardness and Oxidation Resistance of New Generation Ceramic Coatings written by Minghui Zhang (Ph.D.) and published by . This book was released on 2019 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work was motivated by the demand for a new generation of materials capable for harsh environment applications, and focused on developing a better understanding of the effects of elemental composition and microstructure on the mechanical and thermal properties of coatings. The knowledge gained from this work can be used to design protective coatings with tailored properties for harsh environment applications in the future. High resolution transmission electron microscopy (HRTEM) and electron diffraction have been mainly employed in the microstructure studies of the new generation ceramics, with the assistance of other materials characterization techniques, such as x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and nano-indentation measurements. Ceramic coatings studied in this work have been divided into two groups: 1) Transition metal based nanocomposite coatings with enhanced hardness, 2) Amorphous coatings with high oxidation resistance. In the first group, the microstructure effects and hardness enhancement mechanism of Zr-B-C-N, Hf-B-Si-C and Hf-Si-N coatings are discussed. The hardness enhancement is based on the design of nanostructure and the control of grain size during the formation of coatings. The formation of amorphous boundaries with proper thickness between crystalline structures and the well aligned crystallographic orientation were found to result in the increasing of hardness and decreasing of compressive stress of coatings. In the second group, a mechanism of extraordinary high oxidation resistance is established for the Si-B-C-N and Hf-B-Si-C-N coatings by studying the microstructure evolution as a function of being exposed to high temperatures. The results showed that the oxidation resistance enhancement of coatings was based on the suppression of crystallization. The oxidation resistance increases with increasing thermal stability of amorphous structure. Amorphous coatings containing phases can react with oxygen will hinder the ingress of oxygen and prevent further oxidation by forming barrier layers. Two new nanostructures can result in the hardness enhancement have been discovered: 1) Grains composed of sub nano-domains with same orientation separated by semicoherent monolayer boundaries observed from the Zr41B30C8N20 coating; 2) The columnar structures which grow on multilayers, consisting a bundle of small subdomains separated by thin boundaries observed from the Hf-Si-N coating deposited with 15% nitrogen in the gas mixture. Further studies of amorphous coatings with outstanding oxidation resistance indicated that the barrier layers consisting of grains dispersed in amorphous matrix can provide good protection for substrate against oxidation. A compromise between the oxidation resistance and hardness can be reached if nanocomposite coatings are composed of small amount of nanograins embedded in amorphous matrix.

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

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Oxidation of Tungsten written by Vincent David Barth and published by . This book was released on 1961 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report presents a detailed review of available information on the oxidation of W and its alloys. W is relatively inert below 700 C. As the temperature is increased above this level, however, oxidation becomes progressively more rapid, reaching catastrophic rates at temperatures around 1200 C and above. Various theories for the mechanism and rates of W oxidation at different temperatures are reviewed, and the effect of pressure and water vapor on the stability of W oxides is discussed in detail. The elevatedtemperature reactions of W with other materials, such as refractory oxides, and with gases other than oxygen also are covered. Information on the protection of W by alloying and coating is included. (Author).

Download or read book Composites Industry Abstracts written by and published by . This book was released on 1996 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advanced Ceramic Coatings and Materials for Extreme Environments II Volume 33 Issue 3 written by Dongming Zhu and published by John Wiley & Sons. This book was released on 2012-12-10 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: Exploring advanced ceramic coatings and ultra-high temperature ceramic materials, this issue brings readers up-to-date with important new and emerging findings, materials, and applications. The nineteen papers in this issue originate from two symposia and one focused session held in January 2012, during the 36th International Conference on Advanced Ceramics and Composites (ICACC). With contributions from leading ceramics and materials researchers from around the world, this issue explores the latest advances and key challenges in advanced thermal and environmental coating processing and characterizations, advanced wear corrosion-resistant, nanocomposite, and multi-functional coatings, thermal protection systems, and more.