Syntheses and crystal structures of Si-bearing layered carbides ZrAl₈C₇ and ZrAl₄C₄

抄録

Two types of new quaternary carbide solid solutions, (ZrC)[Al_1-xSi_x]₈C₆ with x = 0.06 and (ZrC)[Al_1-ySi_y]₄C₃ with y = 0.04, have been synthesized and characterized using a laboratory X-ray powder diffraction (Cu K α₁), transmission electron microscopy and energy dispersive X-ray spectroscopy (EDX). The average atom ratios [Al:Si] of both carbides were determined by EDX, and the crystal structures were refined using the Rietveld method. These carbides have been found to form a homologous series with the general formula (ZrC)_m[Al_1-zSi_z]₈C₆ (0 ≤ z ≤ 0.07), where m = 1 and 2. The crystal structures can be regarded as intergrowth structures, consisting of the NaCl-type [Zr_mC_m+1] slabs separated by the Al₄C₃-type [(Al_1-zSi_z)₈C₇] layers.