Examinando por Autor "De Miguel, C."

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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.
Restringido
Vacuum tribological behaviour of self-lubricating quasicrystalline composite coatings
(Wiley, 2006-03-09) García de Blas, F. J.; Román, A.; De Miguel, C.; Longo, Federico; Muelas Gamo, Raúl; Agüero, A.
High-temperature-resistant self-lubricating coatings are needed in space vehicles for components that operate at high temperatures and/or under vacuum. Thick composite lubricant coatings containing quasicrystalline alloys as the hard phase for wear resistance can be deposited by a thermal spray technique. The coatings also contain lubricating materials (silver and BaF2CaF2 eutectic) and NiCr as the tough component. This paper describes the vacuum tribological properties of TH103, a coating of this type, with a very good microstructural quality. The coating was deposited by high-velocity oxygen fuel spraying and tested under vacuum using a pin-on-disc tribometer. Different loads, linear speeds, and pin materials were studied. The pin scars and disc wear tracks were characterised using a combination of scanning electron microscopy and energy dispersive spectrometry. A minimum mean steady friction coefficient of 0.32 was obtained when employing an X750 Ni superalloy pin in vacuum conditions under 10 N load and 15 cm/s linear speed, showing moderate wear of the disc and low wear of the pin.