Dense silicon carbide (SiC) matrix composites with SiC whiskers and particles as reinforcement were prepared by infiltrating molten Si at 1550 °C into porous preforms composed of pyrolysed rice husks (RHs) and extra added SiC powder in different ratios. The Vickers hardness of the composites showed an increase from 18.6 to 21.3 GPa when the amount of SiC added in the preforms was 20% (w/w), and...

We report the results of a study of 81 micrometer-sized presolar SiC grains in the size range 0.5–2.6 m from the Murchison (CM2) carbonaceous chondrite. We describe a simple, nondestructive physical disaggregation technique used to isolate the grains while preserving them in their pristine state, as well as the scanning electron microscopy energy-dispersive X-ray mapping procedure used to locat...

We investigate the small-particle phonon-polariton response of several microstructures that are made of silicon carbide (SiC). Phonon polaritons can be excited in a wavelength region between 10 and 12 mm. Simple structures such as elliptical cylinders support phonon polaritons at two wavelengths, which depend on the axis ratio of the particle. In particles with a more irregular shape such as re...

Preparation and characterisation of a highly active and stable beta zeolite supported on a pre-shaped silicon carbide catalyst for the benzoylation reaction in liquid phase.

We investigate the composition and shape distribution of silicate dust grains in the interstellar medium. The effects of the amount of magnesium and iron in the silicate lattice are studied in detail. We fit the spectral shape of the interstellar 10 µm extinction feature as observed towards the galactic center using various particle shapes and dust materials. We use very irregularly shaped coat...

We report the realization of the optically induced inverse population of the ground-state spin sublevels of the silicon vacancies (V(Si)) in silicon carbide (SiC) at room temperature. The data show that the probed silicon vacancy spin ensemble can be prepared in a coherent superposition of the spin states. Rabi nutations persist for more than 80 μs. Two opposite schemes of the optical alignment...

J. Llorca Departamento de Ciencia de Materiales, Universidad Politécnica de Madrid, E. T. S. de Ingenieros de Caminos, 28040 Madrid, Spain; and Instituto Madrileño de Estudios Avanzados en Materiales (IMDEA-Materiales) E. T. S. de Ingenieros de Caminos, 28040 Madrid, Spain K.T. Faber Department of Materials Science and Engineering, Robert R. McCormick School of Engineering and Applied Science, ...