Preparation of R-α′-β′-Sialons (R = Sm, Gd, Dy, Y and Yb) by pressureless sintering

Abstract

Abstract R-α′-β′-Sialon (R = Sm, Gd, Dy, Y and Yb) compositions with a nominal 1 : 1 weight ratio of α′ and β′ have been prepared. Nearly fully dense α′-β′-sialon materials were obtained by pressureless sintering at 1800°C. The phase distribution was determined by both X-ray diffraction and image analysis of SEM micrographs. The atomic number of rare earth elements has a significant effect on the phase distribution. With increasing atomic number the ratio α′ (α′ + β′) increases and the amount of liquid phase decreases. The influences of rare earth elements on the microstructure and mechanical properties were also studied.