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Investigation of the microstructure of SiC-Zn nanocomposites by microscopic methods: SEM, AFM and TEM
|Anna Swiderska - Sroda 1, Jan Kozubowski , Agnieszka Maranda-Niedbala 2, Ewa Grzanka 1,4, Bogdan F. Palosz 1, Adam M. Presz 1, Stanisław Gierlotka 1, Svitlana Stelmakh 1, Grzegorz Kalisz 1,5, Christian Lathe 3|
1. Polish Academy of Sciences, High Pressure Research Center (UNIPRESS), Sokolowska 29/37, Warszawa 01-142, Poland
Bulk SiC-Zn nanocomposites with about 20% volume fraction of metal were fabricated through a high-pressure infiltration process under pressures in the range of 2-8 GPa and temperatures in the range of 400-1000oC. Ceramic powders used in the experiments were loosely agglomerated by Van der Waals forces. The dimensions of the agglomerates were in the micrometer range with individual particles 10-30 nm in diameter. Investigations of the microstructure were performed at different resolution levels using scanning, transmission, and atomic force microscopy techniques. The samples were mechanically polished and ion-etched. The observations of the mechanically polished surfaces show a nano-dispersed mixture of two phases with some zinc-rich regions. AFM shows a smooth surface with the roughness on the order of the SiC grain size (10-30 nm). After subsequent ion etching the SEM images of the samples show homogenous surface composition while AFM topographs indicate surface irregularities: periodically spaced 100 nm high hillocks. Apparently ion etching removes selectively the zinc-rich areas exposing inhomogenity in the bulk of the material. Grain size, grain size distribution, and dispersion of the phases were investigated with TEM technique. The observations indicate a presence of homogeneous (on a sub-micron scale) distribution of two phases with parallel metal streaks across the sample volume. HRTEM images show thin metal layers separating SiC grains. The grain size of the ceramic component remains equal to that of the initial powder. The grain size of Zn was found to depend on the SiC particle size and the composite fabrication conditions.
Presentation: poster at E-MRS Fall Meeting 2003, Symposium G, by Anna Swiderska - Sroda
See On-line Journal of E-MRS Fall Meeting 2003
Submitted: 2003-06-25 12:56 Revised: 2009-06-08 12:55