Download or read book Diffusion and High Temperature Oxidation of Nickel aluminum Based Composite Coatings written by Donald F. Susan and published by . This book was released on 1999 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt: The diffusion and oxidation behavior of electrodeposited composite coatings were studied using thermogravimetric analysis, electron probe microanalysis, and microstructural characterization techniques. Deposition of Al and Al-Si particles into a Ni matrix produced binary and ternary composite coatings with a uniform particle distribution. During heat treatment, coating morphological development was found to occur by the exothermic reaction Ni + Al & rarr; NiAl followed by interdiffusion to form a final gamma + gamma' microstructure. During oxidation at 800°C, the gamma + gamma ' coatings formed a gamma-A12O3 layer below an outer NiO scale. At 1000°C, theta-Al2O3 needles are formed in the early stages. At later times, an alpha-Al2O3 layer is found below an outer spinel NiAl2O4 scale. At both temperatures, the Al2O3 layer provides good oxidation resistance during long-term exposure. The coatings were compared to bulk Ni-Al alloys, and a critical Al content of about 6 wt. % was found, below which internal oxidation attack may occur. During exposure at high temperatures, interdiffusion occurs between the Ni-Al coating and the Ni substrate. The diffusion process was modeled using an analytical solution to Fick's second law. The Al content at the coating surface was monitored using EPMA and the results were in agreement with the predicted values from the diffusion equation. Estimates of coating lifetime were made by combining the diffusion results with knowledge of the effect of Al content on oxidation behavior. The results showed that practical use temperatures for Ni-Al coatings are 700--800°C. At 1000--1100°C, Al depletion begins after a few hundred hours and predicted coating lifetimes are in the range of a few thousand hours.

Download or read book DIFFUSION AND HIGH TEMPERATURE OXIDATION OF Ni Al BASED COMPOSITE COATINGS written by and published by . This book was released on 2001 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Behavior of Chemical Nickel Plate on Aluminum Alloys in High Temperature Dynamic Aqueous Systems written by A. B. Johnson (Jr.) and published by . This book was released on 1964 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1992 with total page 1572 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 High Temperature Oxidation Behavior of Gamma Ni gamma Ni3Al Alloys and Coatings Modified with Pt and Reactive Elements written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Materials for high-pressure turbine blades must be able to operate in the high-temperature gases (above 1000 C) emerging from the combustion chamber. Accordingly, the development of nickel-based superalloys has been constantly motivated by the need to have improved engine efficiency, reliability and service lifetime under the harsh conditions imposed by the turbine environment. However, the melting point of nickel (1455 C) provides a natural ceiling for the temperature capability of nickel-based superalloys. Thus, surface-engineered turbine components with modified diffusion coatings and overlay coatings are used. Theses coatings are capable of forming a compact and adherent oxide scale, which greatly impedes the further transport of reactants between the high-temperature gases and the underlying metal and thus reducing attack by the atmosphere. Typically, these coatings contain [beta]-NiAl as a principal constituent phase in order to have sufficient aluminum content to form an Al2O3 scale at elevated temperatures. The drawbacks to the currently-used [beta]-based coatings, such as phase instabilities, associated stresses induced by such phase instabilities, and extensive coating/substrate interdiffusion, are major motivations in this study to seek next-generation coatings. The high-temperature oxidation resistance of novel Pt + Hf-modified [gamma]-Ni + [gamma]-Ni3Al-based alloys and coatings were investigated in this study. Both early-stage and 4-days isothermal oxidation behavior of single-phase [gamma]-Ni and [gamma]'-Ni3Al alloys were assessed by examining the weight changes, oxide-scale structures, and elemental concentration profiles through the scales and subsurface alloy regions. It was found that Pt promotes Al2O3 formation by suppressing the NiO growth on both [gamma]-Ni and [gamma]'Ni3Al single-phase alloys. This effect increases with increasing Pt content. Moreover, Pt exhibits this effect even at lower temperatures (~970 C) in the very early stage of oxidation. It was also inferred that Pt enhances the diffusive flux of aluminum from the substrate to the scale/alloy interface. Relatively low levels of hafnium addition to Pt-free [gamma]'-Ni3Al increased the extent of external NiO formation due to non-protective HfO2 formation. Accordingly, this effect intensified with increasing Hf content from 0.2 to 0.5 at.%.

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.

Download or read book The Science and Engineering of Thermal Spray Coatings written by Lech Pawlowski and published by John Wiley & Sons. This book was released on 2008-04-30 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: This extensively updated and revised version builds on the success of the first edition featuring new discoveries in powder technology, spraying techniques, new coatings applications and testing techniques for coatings -- Many new spray techniques are considered that did not exist when the first edition was published! The book begins with coverage of materials used, pre-spray treatment, and the techniques used. It then leads into the physics and chemistry of spraying and discusses coatings build-up. Characterization methods and the properties of the applied coatings are presented, and the book concludes with a lengthy chapters on thermal spray applications covers such areas as the aeronautics and space, automobiles, ceramics, chemicals, civil engineering, decorative coatings, electronics, energy generation and transport, iron and steel, medicine, mining and the nuclear industries.

Download or read book Aerospace Materials Handbook written by Sam Zhang and published by CRC Press. This book was released on 2016-04-19 with total page 763 pages. Available in PDF, EPUB and Kindle. Book excerpt: Whether an airplane or a space shuttle, a flying machine requires advanced materials to provide a strong, lightweight body and a powerful engine that functions at high temperature. The Aerospace Materials Handbook examines these materials, covering traditional superalloys as well as more recently developed light alloys. Capturing state-of-the-art d

Download or read book Superalloys written by Nataliya V. Kazantseva and published by CRC Press. This book was released on 2018-12-07 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: Superalloys form a class of the structural materials for high-temperature applications. Nickel superalloys are extensively used in the high-temperature components of gas turbines due to their excellent creep, fatigue, and corrosion resistance at elevated temperatures. These materials are considered paramagnetic in the range of working temperatures. This book presents the features of the ternary phase diagrams Ni-Al-X (X = {Co, Fe, Nb, Ti, Cr}), effects of the alloying on the long-range order and mechanical properties of the Ni3 Al-based alloys. Description of the strain-induced ferromagnetism in the Ni3Al-based alloys and magnetic control of the failure of gas turbine blades are also included. A separate section is devoted to the analysis of the vibration process and strength change in the single-crystal gas turbine blades. This book includes the review of the new intermetallic cobalt superalloys. The structure, crystal lattice parameters, orientation relationships between phases, mechanical and magnetic properties of the Co3(Al,W)-based alloys are described. Non-destructive magnetic point control of the martensite content in low-magnetic austenitic alloys is a new method for detection of the local sites with internal stresses. This method is useful for the detection of the residual stress in the critical parts of industrial products. This book may be useful for specialists in material science, first-year postgraduate students taking a class in material science and engineering, and engineers developing new alloys for the gas turbine technology.

Download or read book Proceedings of the International Congress on Metallic Corrosion written by and published by . This book was released on 1984 with total page 694 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reactor Materials written by and published by . This book was released on 1969 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Official Gazette of the United States Patent and Trademark Office written by United States. Patent and Trademark Office and published by . This book was released on 1975 with total page 1150 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976-02 with total page 722 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reactor Core Materials written by and published by . This book was released on 1968 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book ASM Metals Reference Book 3rd Edition written by Michael Bauccio and published by ASM International. This book was released on 1993-01-01 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt: This reference book makes it easy for anyone involved in materials selection, or in the design and manufacture of metallic structural components to quickly screen materials for a particular application. Information on practically all ferrous and nonferrous metals including powder metals is presented in tabular form for easy review and comparison between different materials. Included are chemical compositions, physical and mechanical properties, manufacturing processes, applications, pertinent specifications and standards, and test methods. Contents Overview: Glossary of metallurgical terms Selection of structural materials (specifications and standards, life cycle and failure modes, materials properties and design, and properties and applications) Physical data on the elements and alloys Testing and inspection Chemical composition and processing characteristics