Aeronáutica

URI permanente para esta comunidadhttps://digitalpro.inta.es/handle/20.500.12666/37

Muchas de las líneas de investigación del INTA se centran en el ámbito aeronáutico. Estas líneas van encaminadas a reforzar las competencias en nuevas tecnologías, haciendo especial hincapié a las relacionadas con caracterización de emisiones producidas por turborreactores, investigación en tecnologías del hidrógeno y otras energías renovables, motores cohete con propulsante líquido y sólido, estudio de materiales funcionales, diseño y fabricación de superficies hielofóbicas, recubrimientos protectores para la corrosión por biomasa, estructuras activas avanzadas y robótica, generación avanzada de trayectorias sobre UAVs, aprendizaje automático e inteligencia artificial sobre minería de datos aerodinámicos y actuadores de plasma y sus aplicaciones.

La investigación de la Aeronáutica se materializa en proyectos financiados con fondos propios, como por ejemplo GERD, que trata del estudio de las condiciones y las tipologías de formación de hielo en superficies. Actualmente se están finalizando las tareas de implementación del nuevo de viento de engelamiento, único en el país, duplicando la capacidad de realización de ensayos en condiciones de formación de hielo.

En el sector aeronáutico del INTA cabe destaca el CIAR, un centro de ensayos en vuelo innovador, que proporciona apoyo técnico y logístico en la experimentación de sistemas de vuelo no tripulados en el ámbito de operación civil o dual y el CEDEA, un centro de ensayos para caracterización de aeronaves y sus componentes tanto tripuladas como no tripuladas, experimentación de misiles, cohetes e I+D de proyectos aeronáuticos de energía y estudio de la atmósfera.

Otros campos de investigación relacionados con la Aeronáutica son la tecnología del vuelo, la aerodinámica teórica y experimental, materiales y estructuras, desarrollo de pinturas, estudio de nuevas fuentes de energía, con programas de I+D dentro del campo de la propulsión y de su aplicación aeroespacial, estudio del impacto medioambiental de los propulsantes y trabajos relacionados con los combustibles y lubricantes en el ámbito aeroespacial y de la Defensa Nacional.

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Mostrando 1 - 20 de 53

Acceso Abierto
10,000 h molten salt corrosion testing on IN617, uncoated and aluminide ferritic steels at 580 ºC
(Richter C., 2020-12) Agüero, Alina; Audigié, Pauline; Sergio, Rodríguez Catela; European Commission (EC)
Long term testing of two ferritic-martensitic steels (P91 and VM12-SHC) with and without slurry deposited aluminide coatings containing 20 wt.% of Al at the surface was carried out by exposing these materials to the Solar Salt, a eutectic mixture composed of 60 % NaNO3 - 40 % KNO3 at 580ºC. This salt is currently used in operating thermal solar power plants as heat transfer and storage fluid. Tubes made of expensive Ni based alloys are employed to mitigate corrosion. The tested uncoated ferritic materials exhibited very high corrosion rates developing thick, easily detached scales. IN617 was also tested as a reference and experienced very low corrosion up to 5,000 h, but after 10,000 h a 50 ȝm thick, mostly NiO scale had developed with Na0.6CoO2 crystals deposited on top. There was also evidence of significant Cr depletion at the alloy surface. Carcinogenic CrVI was found in the Solar Salt melt in which the three uncoated alloys were immersed. In contrast, the two coated ferritic steels did not show evidence of degradation after 10,000 h and the most significant microstructural change was the development of a very thin protective NaAlO2 layer on their surface. An industrial process to deposit these coatings on the inner surfaces of pipes has already been developed.
Acceso Abierto
A direct comparative study of the corrosion behaviour of Si-free and Si-rich slurry aluminide coatings in molten carbonate melts
(LNEG Laboratorio Nacional de Energia e Geologia, 2022-11-24) Audigié, Pauline; Sergio, Rodríguez Catela; Agüero, Alina; Pedrosa, Fátima; Paiva, Teresa; Diamantino, Teresa
ABSTRACT: This study is focused on the evaluation of the hot corrosion behaviour of two low-cost slurry aluminide coatings with and without Si addition deposited on ferritic-martensitic steels, comparing them with uncoated steel, after 1000-h of exposure to Li, K, Na molten carbonates at 650ºC, under static and dynamic conditions with a high linear velocity (1.3 m/s). Both coatings evidenced a high performance increase in comparison with uncoated substrates after exposure in both conditions. Both coatings behaved in a similar way according to the gravimetric results. However, after dynamic exposure, the Si-free aluminide maintained its morphology and composition after 1000 h with α-LiAlO2 as the only corrosion product while the Si-rich coating showed a higher attack extent in the outer part and developed a large quantity of voids at the coating/substrate interface, leading to substrate corrosion.
Restringido
A simple lab screening test to evaluate ice adhesion
(Elsevier, 2025-09) García, Paloma; Mora, Julio; Agüero, Alina; Ministerio de Economía y Competitividad (MINECO)
Ice formation is a major problem for many sectors such as aeronautics, power generation, maritime, communications, etc. and therefore, there is a growing demand for anti-icing surface modification technologies. Being able to compare and evaluate these materials at the laboratory scale is a challenge for which a unified response has not yet been given. There are no standards for evaluating icephobicity despite the fact that there are numerous studies focused on the influence of the surface topography on the wetting behavior. In addition, several testing options have been published both for the evaluation of ice accretion, mainly focused on ice wind tunnels (IWT), and on ice to substrate adhesion, as for instance the zero degree cone test, DLST, Cantilever, centrifugal tests, etc. This article describes a method developed to carry out a simple screening evaluation of ice adhesion by the double lap shear test (DLST) method. This technique can provide qualitative ice adhesion information and is commonly available in research laboratories. Moreover, it does not require icing wing tunnel testing. Its ease of execution and reproducibility makes it a useful tool for a first stage evaluation of anti-icing surfaces despite the fact that ice is formed under static conditions. Various materials and surface finished surfaces with different degree of ice adhesion strength were evaluated and were also tested in a centrifugal adhesion test with ice accreted in an IWT. The results showed that the DLST is valid for ice adhesion classification of materials, but shows limitations for those superhydrophobic materials that are in the Cassie-Baxter state.
Acceso Abierto
A slurry coating for Cd replacement for aircraft components
(Mondragon Unibertsitatea, 2008-07-25) Agüero, Alina; Blanco, C; Gutiérrez del Olmo, Marcos; García Martínez, María
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Al Slurry Coatings for Molten Carbonate Fuel Cell Separator Plates
(Scientific.Net, 2001-01-20) Agüero, Alina; García, M. C.; Muelas Gamo, Raúl; Sánchez, A.; Pérez, Francisco J.; Duday, David; Hierro, M. P.; Gómez, Consuelo
The corrosion behaviour of Al slurry coated AISI 310 stainless steel, with and without diffusion heat treatment, was investigated as a wet seal material for molten carbonate fuel cell (MCFC) at 650°C. The results were compared with IVD Al coated AISI 310. Characterization of the samples before and after exposure to the eutectic 62 mol% Li2CO3-38 mol% K2CO3 mixture at 650°C for 1000 h by SEM-EDS and XRD was carried out. The presence of LiAlO2 on the coated samples was confirmed by XRD. The slurry Al-coated stainless steels performed at least as well as the IVD Al coating.
Acceso Abierto
Aluminide Coatings by Means of Slurry Application: A Low Cost, Versatile and Simple Technology
(MPDI, 2024-09-29) Agüero, Alina; Audigié, Pauline; Lorente Sánchez, Cristina; Gutiérrez del Olmo, Marcos; Mora, Julio; Sergio, Rodríguez Catela; European Commission; Agencia Estatal de Investigación (España)
The present study focused on demonstrating the versatility of the slurry deposition technique to produce aluminide coatings to protect components from high-temperature corrosion in a broad temperature range, from 400 to 1400 °C. This is a simpler and low-cost coating technology used as an alternative to CVD and pack cementation, which also allows the coating of complex geometries and offers improved and simple repairability for a lot of industrial applications, along with avoiding the use of non-hazardous components. Slurry aluminide coatings from a proprietary water-based-Cr6+ free slurry were produced onto four different substrates: A516 carbon steel, 310H AC austenitic steel, Ti6246 Ti-based alloy and TZM, a Mo-based alloy. The resulting coatings were thoroughly characterised by FESEM and XRD, mainly so that the identification of microstructures and appropriate phases was reported for each coating. The importance of surface preparation and heat treatment as key parameters for the coating final microstructures was also evidenced, and how those parameters can be optimised to obtain stable intermetallic phases rich in Al to sustain the formation of a protective Al2O3 oxide scale. These coating systems have applications in diverse industrial environments in which high-temperature corrosion limits the lifetime of the components.
Restringido
Aluminum slurry coatings to replace cadmium for aeronautic applications
(Elsevier, 2012-10-27) Agüero, Alina; del Hoyo Gordillo, Juan Carlos; García de Blas, Javier; García, M.; Gutiérrez, M.; Madueño, L.; Ulargui, S.
Cadmium has been widely used as a coating to provide protection against galvanic corrosion for steels and for its natural lubricity on threaded applications. However, it is a toxic metal and a known carcinogenic agent, which is plated from an aqueous bath containing cyanide salts. For these reasons, the use of cadmium has been banned in Europe for most industrial applications. However, the aerospace industry is still exempt due to the stringent technical and safety requirements associated with aeronautical applications, as an acceptable replacement is yet to be found. Al slurry coatings have been developed as an alternative to replace cadmium coatings. The coatings were deposited on AISI 4340 steel and have been characterized by optical and electron microscopy. Testing included salt fog corrosion exposure, fluid corrosion exposure (immersion), humidity resistance, coating-substrate and paint-coating adhesion, electric conductivity, galvanic corrosion, embrittlement and fatigue. The results indicated that Al slurry coatings are an excellent alternative for Cd replacement.
Restringido
Anomalous steam oxidation behavior of a creep resistant martensitic 9 wt. % Cr steel
(Elsevier, 2013-06-09) Agüero, Alina; González, Vanessa; Mayr, Peter; Spiradek Hahn, Krystina; Ministerio de Economía y Competitividad (MINECO)
The efficiency of thermal power plants is currently limited by the long-term creep strength and the steam oxidation resistance of the commercially available ferritic/martensitic steel grades. Higher operating pressures and temperatures are essential to increase efficiency but impose important requirements on the materials, from both the mechanical and chemical stability perspective. It has been shown that in general, a Cr wt. % higher than 9 is required for acceptable oxidation rates at 650 °C, but on the other hand such high Cr content is detrimental to the creep strength. Surprisingly, preliminary studies of an experimental 9 wt. % Cr martensitic steel, exhibited very low oxidation rates under flowing steam at 650 °C for exposure times exceeding 20,000 h. A metallographic investigation at different time intervals has been carried out. Moreover, scanning transmission electron microscopy (STEM) analysis of a ground sample exposed to steam for 10,000 h at 650 °C revealed the formation of a complex tri-layered protective oxide comprising a top and bottom Fe and Cr rich spinel layer with a magnetite intermediate layer on top of a very fine grained zone.
Acceso Abierto
Behaviour of coated and uncoated ferritic steels under isothermal and cyclic steam oxidation conditions
(VTT, 2007-06-14) Agüero, Alina; González, Vanessa; Gutiérrez, M.
Next generation steam turbines are expected to operate at 600-650°C and at these temperatures, currently available high strength ferritic-martensitic steels need to be coated to prevent oxidation. Slurry deposited aluminide coatings have shown excellent performance up to 650°C under isothermal conditions. The behaviour of these coatings as well as that of uncoated P92 under thermal cycling conditions has been studied both in steam and in air at 650°C. The tested specimens were characterized by field emission scanning electron microscopy. A comparison with isothermal steam oxidation has been established. In cyclic oxidation, evidence of scale spallation from uncoated substrates was observed at shorter exposure times than for specimens tested under isothermal conditions. In the coated specimens, cracks originally present in the "as deposited" coating did not propagate or become sites of preferential oxidation during isothermal steam testing. However, the cracks widened and propagated causing substrate oxidation when the specimens were tested by thermal cycling in steam or in air.
Acceso Abierto
Co-ordination of European Research in Structural Materials for Power Generation Equipment
(University of Liège, 2014-09-17) Sommitsch, Chrisof; Vanstone, Rod; Kern, Torsten Ulf; Barnard, Peter; Mayr, Peter; Thompson, Rachel; Agüero, Alina
Sommitsch, C., Vanstone, R., Kern, T.-U., Barnard, P., Mayr, P., Thomson, R., & Agüero, A. (2014). Co-ordination of European Research in Structural Materials for Power Generation Equipment. In Liège Conference on Materials for Advanced Power Engineering (Vol. Band / Volume 234, pp. 3-18). (Schriften des Forschungszentrums Jülich, Reihe Energie & Umwelt / Energy & Environment). ..
Acceso Abierto
Coatings for Oxycombustion - Supercritical Steam Boilers Components
(University of Hakodate, 2014-01-21) Agüero, Alina; Baraibar, Ignacio; González, Vanessa; Gutiérrez del Olmo, Marcos; Muelas Gamo, Raúl; Plana, Daniel
[1] CO2 Capture Technologies: Oxi Combustion with CO2 Capture, Global CCS Institute, Palo Alto, CA, January 2012 http://www.globalccsinstitute.com/publications/co2-capture-technologies-oxy-combustion-co2-capture [2] Production of Coatings for New Efficient and Clean Coal Power Plant Materials (POEMA), FP7 Program, G.A. No.: 310436, 2013-2016. [3] Agüero A., González V., Gutiérrez M., Knödler R., Muelas R. and Straub S., Comparison between Field and Laboratory Steam Oxidation Testing of Aluminide Coatings on P92, Materials and Corrosion, Vol. 62 (2011), pp. 561-568 [4] Agüero A., González V., Gutiérrez M. and Muelas R., Oxidation under pure steam: Cr based protective oxides and coatings, Surface and Coatings Technology, 237 (2013) 30-38 [5] Agüero A., Progress in the Development of Coatings for Protection of New Generation Steam Plant Components, Energy Materials, 3 (2008) 35-44 [6] R. Muelas and A. Agüero, INTA, unpublished results.
Restringido
Comparison between field and laboratory steam oxidation testing on aluminide coatings on P92
(Wiley online library, 2011-01-12) Agüero, Alina; González, V; Gutiérrez del Olmo, Marcos; Knödler, R; Straub, S; Muelas Gamo, Raúl; Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Steam oxidation has become an important issue for steam power plants as operating temperatures increase from the current 550 to 600–650 °C. For the last 10 years several groups have been carrying out steam oxidation testing of both uncoated substrates and coatings in the laboratory. On the other hand, field testing results are very scarce. In this paper, a comparison of laboratory steam oxidation testing with field test results carried out by Alstom at the Kraftwerk Westfalen power station located in Hamm, Germany will be presented. Both slurry deposited aluminide coatings and uncoated P92 steel have been included in the study. Under steam (atmospheric pressure) and isothermal conditions in the laboratory at 650 °C, spallation of oxides formed on ferritic steels occurs after significantly longer time when compared to exposure to real operating conditions. Oxide spallation results in serious damage in steam power plants by obstructing heat exchanger tubes, erosion of valves and turbine blades, etc. Moreover, the thickness of the oxide scales formed under field testing conditions is significantly higher after similar exposure. On the other hand, aluminide coated P92, which exhibit thickness through cracks, have shown to be stable in the laboratory for up to 60 000 h at 650 °C under steam, without evidence of crack propagation. However, field test results indicate that some degree of crack propagation occurs but without causing substrate attack up to 21 700 h of exposure. Moreover, the aluminium oxide observed in both laboratory and field tested specimens is different.
Acceso Abierto
Comparison between pilot and lab scale testing of aluminide coated and uncoated ferritic steels under oxy-fuel and coal/thistle co-firing conditions
(Elsevier, 2022-11-25) Gutiérrez, M.; Illana, Andrea; Bahillo, Alberto; Benito, Manuel J.; García Martín, G.; Pérez Trujillo, Francisco Javier; Agüero, Alina; European Commission (EC); Universidad Complutense de Madrid(UCM)
The present study compares the biomass corrosion behavior of two diffusion aluminide coating obtained by slurry application, which were deposited on two low-chromium content steels, ferritic-martensitic P92 (8.7 wt% Cr) and ferritic T22 (2 wt% Cr). Their performance degradation was conducted under an oxy-fuel combustion environment for both coated and uncoated materials both under laboratory conditions and in a pilot plant burning thistle for 500 h. Exposures were carried out in the laboratory at two different temperatures, 600 °C and 650 °C, under a model atmosphere consisting of 60 % CO2, 30 % H2O, 8 % O2, bal.% N2 (in vol%), 500 vppm HCl and 2 vppm SO2. The pilot plant used a mixed fuel of 60 wt% coal and 40 wt% thistle that was burnt and the samples were exposed to a temperature range of 600–620 °C. After testing, the results revealed that the aluminide-coated materials exhibited a very high resistance under both extreme scenarios, with a variable protective character related to their Al content. On the contrary, uncoated material exhibited severe degradation, in particular T22. Microstructural and morphological studies showed up similar corrosion patterns and products on coated and uncoated materials for both testing environments.
Restringido
Comparison of descaling methods to study the corrosion kinetics of ferritic steels after dynamic exposure to molten carbonates
(Elsevier, 2022-12-24) Audigié, Pauline; Sergio, Rodríguez Catela; Agüero, Alina; Pedrosa, Fátima; Paiva, Teresa; Diamantino, Teresa C.
T91 ferritic-martensitic steel was exposed to Li, Na and K molten carbonates at 650ºC under dynamic conditions up to 1000 h. After testing, three descaling methods, two from the ISO8407 and one from the ISO17245 standards were applied to remove the corrosion products and determine the corrosion rates. The two ISO8407 methods were more appropriate although the procedure required several steps to fully remove the corrosion products. The ISO17245 method led to a higher mass loss affecting probably the base material. Oxides identification was performed by XRD following step by step layers removal. Li-, Na-, K-containing oxides and chromates/chromites were detected.
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Corrosion Resistance of Novel Coatings on Ferritic Steels for Oxycombustion–Supercritical Steam Boilers: Preliminary Results
(Springer Nature Link, 2015-07-23) Agüero, Alina; Baraibar, Ignacio; González, Vanessa; Muelas Gamo, Raúl; Plana, Daniel; European Commission; Ministerio de Economía y Competitividad (MINECO)
Increasing the efficiency of coal fired steam power plants is an important contribution towards clean coal power. In fact, new ferritic steels are expected to withstand 325 bar and 650 °C. Moreover, in order to facilitate CO2 capture oxygen can be used instead of air for combustion (oxycombustion) so that no NOX emissions are produced. Boiler components, such as superheater tubes, are exposed to both steam and fireside corrosion and at higher temperatures, ferritic steels corrode at very fast rates under both atmospheres. A solution can be found in the use of protective coatings, a number of which, applied by techniques capable of depositing said coatings both on the inner and outer surfaces of tubes, are being studied within nationally and European funded projects. In particular, two new Ni and Cr modified aluminide coatings deposited on P92 by non-line-of-sight hybrid processes have been produced and the preliminary results of on-going laboratory testing, both under oxycombustion model atmospheres as well as under pure steam at 650 °C are promising, in particular those exhibited by the Cr enriched aluminide coating. Moreover, results obtained in a pilot oxycombustion boiler operated by CIUDEN in Leon, Spain are also shown.
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Cyclic oxidation and mechanical behaviour of slurry aluminide coatings for steam turbine components
(Elsevier, 2007-04-02) Agüero, Alina; Muelas Gamo, Raúl; Gutiérrez del Olmo, Marcos; Van Vulpen, R.; Osgerby, Steve; Banks, J. P.
The excellent steam oxidation resistance of iron aluminide coatings on ferritic steels at 650 °C has been demonstrated both by laboratory tests and field exposure. These coatings are formed by the application of an Al slurry followed by diffusion heat treatment at 700 °C for 10 h. The resulting microstructure is mostly composed of Fe2Al5 on top of a much thinner FeAl layer. This coating exhibits perpendicular cracks due to thermal expansion mismatch between coating and substrate. However, these stress relieving cracks do not seem to have an effect on the mechanical properties of the substrate. Cyclic oxidation, creep resistance and TMF testing of these coatings at 650 °C indicate excellent performance.
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Deposition process of slurry iron aluminide coatings
(Taylor and Francis online, 2008-10-04) Agüero, Alina; Gutiérrez del Olmo, Marcos; González, Vanessa
Diffusion iron aluminide coatings prevent steam oxidation of ferritic/austenitic steels at 650°C for at least 45,000 h. These coatings are deposited by applying Al slurries followed by a diffusion heat treatment at 650°C. The quality of the coatings is very sensitive to a number of factors such as surface preparation, slurry composition and diffusion treatment temperature. A study of the effect of the different processing parameters has been performed in order to optimize the process from an industrial perspective. Moreover, most commercially available Al slurries contain different levels of Cr6+, a highly carcinogenic species, and therefore Cr6+ free slurry formulations have been prepared. In addition, re-coating after exposure has also been developed since it is not clear yet if these coatings will last the 100,000 h which is the life limit for steam power plant design. Based on these studies, processes suitable for coating real size components and re-coating steam exposed components have been developed and are presented in this contribution.
Acceso Abierto
Development and Qualification of New Solid Lubricant Coatings. A Tribology Experiment at the Tribolab onto EUTEF
(Centre national d'études spatiales (CNES), 2000-06-12) Oñate, J. Ignacio; Brizuela, Marta; García Luis, Alberto; Viviente, J. Luis; García de Blas, Javier; Agüero, Alina; Longo, Federico; Román, Alicia
A recent study has identified that a significant number of satellite failures and anomalies, including those caused during qualification testing of mechanisms, were caused by lubrication related problems. Solid lubrication is, owing to lower vapour pressures, better boundary lubrication properties, relative insensitivity to radiation effects and wider temperature range of operation, still a preferred option for a number of space mechanisms. However, actual solid lubricants wear out and do not provide effective protection for long life mechanisms. A longer life and reduced wear debris is desirable to improve mechanism reliability. The present work reports on early results on the development of a new generation of solid lubricant coatings by the use of state of the art magnetron sputtering technology and thermal spraying processes. These coatings after a proper qualification procedure under laboratory ground conditions will be finally tested at the TriboLAB instrument that will be integrated onto the EuTEF facility at the International Space Station (ISS). Metal alloyed MoS2 solid lubricant films have been produced by a magnetron sputtering PVD process. Tribotests carried out under vacuum in a ball-on-disc tribometer with MoS2 coated AISI 440C steel discs have shown very low friction coefficients of 0.01 and long endurance, in excess of 300,000 revolutions at about a max. 0.8 GPa contact stress. These films also exhibited low friction coefficients (about 0.10) and good durability under atmospheric conditions at RT and up to 50 to 60 % RH. The thick composite lubricant coatings consisting of AlCoFeCr, NiCr, Ag and BaF2-CaF2 were deposited by plasma spray and HVOF on X-750 Ni-base superalloy. These coatings have been characterised by EDS-SEM as well as hardness measurements. The best coatings from preliminary experiments have been produced by HVOF process; these show very low porosity, a more uniform phase distribution and hardness levels of 635 HV0.2. Anticipated high temperature applications of former coatings might include elevon hinges for re-usable space planes.
Acceso Abierto
Development and Validation of Advanced Oxidation Protective Coatings for Super Critical Steam Power Generation Plants
(Grafische Medien, 2006-07-06) Scheefer, M.; Bernard Henderson, Michael; Agüero, Alina; Allcock, B.; Norton, B.; Tsipas, D. N.; Durham, R.; European Commission (EC)
Increasing the efficiency of coal-fired power plant by increasing steam temperatures and pressures brings benefits in terms of cheaper electricity and reduced emissions, particularly CO 2 . In recent years the development of advanced 9%Cr ferritic steels with improved creep strength has enabled power plant operation at temperatures up to 600 -620ºC such that these materials are currently being exploited to construct a new generation of advanced coal-fired plant. However, the move to higher temperatures and pressures creates an extremely hostile oxidising and errosive environment. To enable the full potential of the advanced 9%Cr steels to be achieved, it is vital that protective coatings are developed, validated under high pressure steam environments and applied successfully to candidate components from the high pressure steam path. This paper reviews recent work conducted within the Framework V Brite EuRam project "Coatings for Supercritical Steam Cycles" (SUPERCOAT) to develop and demonstrate advanced slurry and thermal spray coating technologies capable of providing steam oxidation protection at temperatures in excess of 620°C and up to 300 bar pressure. The programe of work described has demonstrated the feasibility of applying a number of candidate coatings to steam turbine power plant components and has generated long-term steam oxidation rate and failure data that underpin the design and application processing work packages needed to develop and establish this technology for future and retrofit plant.
Restringido
Effects of a Steam Pre-treatment on the Formation and Transformation of Alumina Phases on Fe Aluminide Coatings
(Springer Nature Link, 2012-12-25) Agüero, Alina; Hernández, M.; Santaballa, A.; Ministerio de Economía y Competitividad (MINECO)
Several researchers have studied the transformation of metastable aluminas (γ- and θ-) to α-Al2O3 but very little is known regarding alumina scales formed under water vapour and their transformation to α-Al2O3. Some results have indicated that water vapour increases the oxidation rate of alumina-scale forming coatings but others have found the opposite, that is, that under water vapour the oxidation rates decrease as either transition aluminas do not form or the transformation to α-Al2O3 is accelerated. In addition, it was found that χ-Al2O3 is the only oxide that forms at the initial stages of oxidation under 100 % steam on Fe–Al coatings at 650 °C. Under these conditions, this oxide is very protective, and slowly transforms onto α-Al2O3. A preliminary study of the transformation of χ- to α-Al2O3 at 900 °C under laboratory air was carried out. χ-Al2O3 was generated by a steam pre-treatment on slurry Fe aluminide coatings deposited on P92.

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Examinando Aeronáutica por Autor "Agüero, Alina"