Abstract: Severe non-stoichiometric spinels obtained in the temperature range from 300 to 1000$^{o}$C are of great catalytical interest. For this samples the problem of cation distribution exists that can not always be solved using integrated intensity refined method. As a rule, the diffraction peaks on the x-ray diagram are significantly broadened and partially overlapped. Usually the broadening of peaks with different crystallographic indexes is anisotropic because of the presence of stacking faults. In this case the standard Rietveld method is not possible to refer. We used the modified program of profile analysis [1] that enabled the individual peaks parameters to be refined. The refinement of non-stoichiometric spinels with Mg-Al-,Co-, Zn-Al- compounds revealed that in some cases the part of cations occupy those octahedral and tetrahedral positions which are vacant in the ideal spinels structure. The cations in the non-spinels positions indicate to the presence of stacking faults in these samples. Also the information on the type and concentration of stacking faults can be obtained from an analysis of the broadening of diffraction peaks. On the basis of Rietveld refinement and profile analysis data the models of stacking faults are proposed.

Cite: Tsybulya S.V. , Solovyeva L.P.
Investigation of the Real Structure of Non-Stoichiometric Spinels Using Profile Analysis
Materials Structure in Chemistry, Biology, Physics and Technology. 1995. V.2. N1. P.63. РИНЦ

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49941465

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