engleski

Synthesis and Characterization of some Clathrate Compounds

In the presented study we report on our work on the characterization of the plastic properties by means of Vickers microhardness measurements of some clathrate compounds prepared by arc melting: Ba₈Ag₅Si₄₁, Ba₈Au₅Si₄₁ and Ba₈Au₆Ge₄₀. The results cannot be explained by taking into account the usual comparison of microhardness with the size of atoms, the density of compounds, the melting temperatures, and by the coefficient of temperature expansion of the compounds. In order to understand the microhardness of the investigated compounds one have to take into account the strength of the Si-Si with respect to the Ge-Ge bonds. But it seems that a full explanation one can get analyzing the Raman spectra from these samples. The analyse indicates the existance of precipitates of Si in the samples containing Si within chlatrate formula. It is known that small sized precipitates hamper and omit moving of dislocations. Therewith the hardness of a material increases.

hardness; clathrates; Raman spectrum

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