Syntheses, crystal structures and Si solubilities of new layered carbides Zr2Al4C5 and Zr3Al4C6

Two types of new tertiary carbides, Zr2Al4C5 and Zr3Al4C6, have been synthesized and characterized by X-ray powder diffraction. The crystal structures were refined from laboratory X-ray powder diffraction data (CuK alpha(1)) using the Rietveld method. These carbides form a homologous series with the general formula (ZrC)(m) Al4C3 (m = 2 and 3). The Crystal Structures can be regarded as intergrowth structures where the Al4C3-type [Al4C4] layers are the same, while the NaCl-type [ZrmCm+1] layers increase in thickness with increasing in value. The new carbides are most probably the end members of continuous solid-solutions (ZrC)(m) [Al4-xSix]C-3 with 0 <= x <= 0.44. (C) 2008 Elsevier Inc. All rights reserved.