MORALES RODRÍGUEZ , Ana

Los materiales compuestos de circona y níquel han despertado un gran interés en los últimos años por ser candidatos idóneos en aplicaciones de alto valor añadido relacionadas con la industria aeroespacial, conversión de energía y sensores de flujo y temperatura. Las condiciones de operación, altas temperaturas en atmósferas vari ables, hacen...

Se han fabricado compuestos de 80% vol. Al2 O3/TZP (ZrO2 estabilizada con 2% mol Y2 O3) codopados con 1% vol. Fe2 O3 y 1% vol. TiO2 mediante la tecnología RBAO ("Reaction Bonding of Aluminum Oxide"), que se han sinterizado libremente (1450 ºC, 60 min) y bajo carga uniaxial (20 MPa, 1200 ºC, 60 min). Se ha caracterizado la microestructura...

Se ha estudiado el comportamiento plástico a alta temperatura de alúmina codopada con cantidades equimolares de óxidos de cobre (CuO) y titanio (TiO2) fabricada por reacción mediante el empleo de ensayos de fluencia y de relajación de tensiones en atmósfera de aire. Los resultados de los ensayos de deformación plástica han sido correlacionados...

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The creep behavior of tetragonal zirconia TZP-Ni cermets with metal contents below, close to, and above the percolation limit has been studied. Compressive creep tests were performed on as-received materials and samples in which the metal phase was chemically removed (ceramic skeletons). The stress exponent and the activation energy for plastic...

The aim of this study is to elucidate the coarsening kinetics involved during densification of fine-grained pure α-alumina by spark plasma sintering. Low temperature and short dwell time sintering conditions were used to preserve the nanocrystalline structure of the starting commercial powder (about 50 nm). Notwithstanding the above, submicron...

The microstructure of 3 mol% Y2O3-stabilized tetragonal ZrO2/Ni (TZP/Ni) composites has been investigated for nickel concentrations of 20, 30 and 40 vol.% before and after creep tests conducted in argon atmosphere at 1250 °C under stresses between 9 and 14 MPa. The microstructures have been characterized using scanning, conventional and...

The influence of an oxidizing atmosphere on the high-temperature plasticity of zirconia/nickel cermets has been studied by conducting creep tests in air. The resulting microstructure has been characterized by scanning, conventional and high-resolution electron microscopy. Despite the large microstructural changes, the composites do not exhibit...

3YTZP matrix composites containing 2.5 vol% of single-walled carbon nanotubes (SWCNT) were fabricated by Spark Plasma Sintering (SPS) at 1250C, following different processing routines with the aim of optimizing the SWCNTs dispersion throughout the ceramic matrix. Microstructural characterization of the as-fabricated samples has been performed...

Yttria tetragonal zirconia polycrystalline (3YTZP) ceramic composites with 5, 10 and 20 vol% graphene nanoplatelets (GNPs) were prepared by spark plasma sintering (SPS) and their electrical conductivity as a function of temperature was characterized. The composites exhibit anisotropic microstructures so the electrical conductivity studies were...

The plastic behavior of cermets based on a 3 mol% yttria-stabilized tetragonal zirconia matrix that incorporates nanometric nickel inclusions (3YTZP/n-Ni), with 2.5, 5 and 10 vol.% of nickel content, has been studied by constant load tests in compression carried out in argon atmosphere. The microstructure of these composites consists of...

The tribological behavior of graphene nanoplatelet (GNP) reinforced 3 mol% yttria tetragonal zirconia polycrystals (3YTZP) composites with different GNP content (2.5, 5 and 10 vol%) was analyzed and discussed. Their dry sliding behavior was studied using a ball-on-disk geometry with zirconia balls as counterparts, using loads between 2 and 20 N...

In this work, novel 3mol% yttria tetragonal zirconia polycristalline (3YTZP) ceramic composites with boron nitride nanosheets (BNNS) are investigated for the first time. Highly densified composites with 1 and 4vol% BNNS were obtained by spark plasma sintering (SPS) after BNNS synthesis using a solution exfoliation method and BNNS dispersion...

3 mol% yttria tetragonal zirconia polycrystalline (3YTZP) ceramic composites with 2.5, 5 and 10 vol% graphene nanoplatelets (GNP) were pressureless sintered in argon atmosphere between 1350 and 1450 °C. The effects of the GNP content and the sintering temperature on the densification, microstructure and electrical properties of the composites...

Graphene oxide (GO) was mixed with 3 mol% yttria tetragonal zirconia polycrystal (3YTZP) using two powder processing routines: a colloidal method in an aqueous solution and a combination of ultrasonication with high-energy planetary ball milling in wet conditions. Highly densified 3YTZP composites with reduced GO (rGO) were consolidated by...