Structural characterization of liquid phase sintered silicon carbide by high-resolution X-ray diffractometry

Abstract

Silicon carbide (SiC) was sintered using two different additives: AlN-Y 2 O 3 or AlN-CRE 2 O 3 . CRE 2 O 3 is a mixed oxide formed by Y 2 O 3 and rare-earth oxides. The crystalline structures of the phases were analyzed by high-resolution X-ray diffraction using synchrotron light source. The results of the Rietveld refinement of the mixed oxide show a solid solution formation. In both silicon carbide samples prepared using AlN-Y 2 O 3 or AlN-CRE 2 O 3 3C (β-phase) and 6H (α-phase) polytypes were found. The structural and microstructural results for both samples were similar. This is an indication of the viability of the use of CRE 2 O 3 in substitution for Y 2 O 3 as additive to obtain dense materials.