Effect of sintering time and composition of sintering aids on the core-rim microstructure and material properties of spark plasma sintered silicon carbide.

摘要

Silicon carbide is an industrial ceramic used for many applications. Due to its complicated crystal structure, many different types exist and can be made to have a “core-rim” microstructure in individual grains. In this work, SiC samples were processed via a co-precipitation and spark plasma sintered to examine the core-rim microstructure by altering the sintering time when spark plasma sintered, the additive amounts, and the polytype composition. Samples were characterized via density, hardness, FESEM, XRD, and Raman analysis depending on the type of samples. The density and hardness of samples showed that the samples for the dwell time studied were densified but the ones of varying polytype were not. The hardness generally increased with longer sintering dwell times, whereas the density measurements were too similar to discern any appreciable difference between samples. The extent of the core-rim structure as seen from FESEM images had a large variability, but preliminary results hint at less core-rim features with longer dwell times. The XRD results were typical of the materials present in the sample and showed a SiO 2 phase.