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Ítem Acceso Abierto Tribolab: An experiment on space tribology(European Space Agency (ESA), 1998-11-05) Gómez Elvira, J.; Oñate, J. Ignacio; Marcos, J.; Rowntree, R.; Agüero, A.The accurate knowledge of the com:pIex behavior of lubricant systems, both solid and liquid, is a fundamental requirement for the reliable operation in orbit of spacecraft mechanisms. Modem spacecraft, of all types, proliferate with mechanisms whose predictable operation is mandatory. In flight a spacecraft mechanism must develop its function under a quite hostile environment, which is made up mainly by space radiation, extreme thermal conditions, vacuum, atomic oxygen and mechanical effects like microvibrations. All those conditions are impossible to simulate simultaneously on ground. Some tribometers flown in the past in order to correlate the flight and ground tests results showed a good correlation of data for simple friction and wear of bulk materials and surface coatings. Nevertheless, new promising materials and processes, never flown before, will be implemented in the experiment to know its behavior against the above mentioned environment and laying stress in }igravity conditions.Ítem Acceso Abierto Quasicrystalline Materials as Thermal Barrier and Hot Corrosion Resistant Coatings(University of Toronto, 1999-10-20) Agüero, A.; Álvarez, J.; García de Blas, F. J.; Sánchez, A.; Villar, I.Ítem Restringido Coatings For Steam Power Plants Under Advanced Conditions(European Cooperation in Science and Technology, 2002-09-12) Agüero, A.; Muelas Gamo, Raúl; Scarlin, B.; Knodler, ReinhardÍtem Restringido Cyclic Oxidation of Steam Pre-oxidized MCrAlY and Ni Aluminide Coatings(Turbine Forum, 2004-08-25) Agüero, A.; Román Gárate, Alicia; Gutiérrez, MarcosSignificant attention has been paid to high temperature oxidation resistant coatings such as overlay MCrAlYs and diffusion Ni aluminide coatings to protect superalloys in both aeronautic and gas turbine components. Both coatings behave as Al reservoirs in order to form a protective Al2O3 layer. Said layer is very stable but grows with exposure time and will also tend to spall due to thermal cycling. Both types of coatings are also employed as bond layers for thermal barrier ceramic coatings (TBCs), which are employed to maintain a lower surface temperature for refrigerated turbine components. The bond coating has a dual function as it reduces the thermal expansion coefficient mismatch between the ceramic layer and the superalloy, and protects the superalloy from environmental degradation due to air as well as other contaminants that will permeate through the porous ceramic top layer. The main cause of failure of TBCs is related to spalling of the ceramic top layer due to stresses resulting from the Al2O3 growth at the bond coating-thermal barrier interface. It has been shown that bond coat pre-treatment prior to the TBC deposition has a strong influence on the oxidation resistance of these coatings. Moreover, recent results by C. Zhou and collaborators have indicated that steam present in air will significantly increase the oxidation rate of TBCs (with MCrAlYs as bond coating) and the cause is attributed to the formation of thick porous mixed oxides related to the presence of steam. The authors suggest that H dissolved into the initially formed oxides enhance Ni and Cr ion outwards diffusion.Ítem Acceso Abierto Latest Results in the Development of Steam Resistant Coatings for New Generation High Temperature Supercritical Steam Plants(Turbine Forum, 2006-03-12) Agüero, A.; Muelas Gamo, Raúl; Gutiérrez, MarcosÍtem 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, A.; 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.Ítem Restringido Characterization of Tribological Quasicrystalline Composite Coatings(Deutscher Verband für Schweisstechnik, 2002-03-06) Román, A.; Agüero, A.; De Miguel, C.; García de Blas, F. J.; Longo, Federico; Muelas Gamo, Raúl; Sánchez, A.Quasicrystalline (QC) alloys constitute a family of materials with low coefficient of friction, high hardness, and high yield strength under compressive stress. This paper examines the characteristics of QC composite coatings deposited by LPPS and HVOF spraying. It compares the coatings based on phase distribution and microstructure. Both compositions studied are extremely wear resistant, but their friction properties require further development. Paper includes a German-language abstract.Ítem Acceso Abierto Coatings for Protection of High Temperature New Generation Steam Plant Components: A Review(Grafische Medien, 2006-04-06) Agüero, A.Ítem Acceso Abierto Behaviour of coated and uncoated ferritic steels under isothermal and cyclic steam oxidation conditions(VTT, 2007-06-14) Agüero, A.; 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.Ítem Restringido Applications of Quasicrystalline materials as Thermal Barriers in Aeronautics and Future Perspective ofUse for these Materials(Springer, 1998-05-05) Sánchez, A.; García de Blas, F. J.; Algaba, J. M.; Álvarez, J.; Vallés González, Pilar; García Poggio, M. C.; Agtiero, A.Quasicrystalline materials (QCs) have very interesting properties which make them good candidates to be used as coatings resistant to wear, high temperature oxidation, corrosion, etc. the potential application of AI71Co13Fe8Co8 (QC1), a quasicrystalline approximant alloy, as a thermal barrier coating (TBC) for components of aeronautical and power generation turbines was explored in our laboratories and the results are presented in this paper. QC1 is stable at I 1000°C and has a thermal conductivity similar to that of yttria stabilized zirconia (YSZ), the most commonly used material for TBCs. QC1 powders were low pressure plasma sprayed on IN100 superalloy and coatings of excellent quality were obtained after a series of optimization experiments. the “as deposited” coatings were characterized by XRD, SEM and TEM and the results indicated that the coatings retained the same microstructure and phase composition as the bulk material. However, when coated specimens were heat treated at 950°C, interdifussion between coating and substrate took place resulting in the transformation of the QC approximant phase. To avoid or retard this process, the effect of several diffussion barrier layers, deposited between substrate and coating, was studied and the results showed that some of these barriers were quite efficient in slowing the diffusion process. Extensive cyclic oxidation and hot corrosion studies were carried out, showing promising results for this new type of TBC coatings. A short term ground engine test was carried out with coated blades.Publicación Acceso Abierto RAISELIFE project extends the lifetime of functional CSP materials(AIP Publishing, 2022-05-12) Sutter, Florian; Binyamin, Yaniv; Zoschke, T.; Fernández García, Aránzazu; Naamane, S.; Galetz, M.; Reoyo Prats, R.; Pérez Trujillo, Francisco Javier; Aglüro, Alina; Orioli, F.; Piron, Javier; Mandler, D.; Attout, A.; Caron, Simon; Wette, J.; Sánchez, Ricardo; Morales, Angel; Hildebrandt, C.; European Commission (EC)The RAISELIFE project was conducted from April 2016 until March 2020 and was funded within the H2020 program of the European Commission (Grant 686008). The project aimed at developing novel materials with extended lifetime and performance for parabolic-trough and solar tower CSP plants and thereby reducing electricity generation costs. In order to assess the expected durability of the novel materials, improved accelerated aging and qualification methods simulating in-service conditions in different climates were developed. The project brought together a broad consortium formed of industry partners, SMEs and research institutes of the CSP and material science sector. This paper summarizes the main developments and takeaways from the RAISELIFE project.
