Microanalytical investigations of the intermediate sintering state of silicon carbide

Abstract

The intermediate state of sintering of boron- and carbon-doped pressureless sinterable silicon carbide was analyzed in situ using analytical transmission electron microscopy (including electron energy loss spectroscopy and energy dispersive analysis of X-rays) as well as high resolution Auger electron spectroscopy. From the results obtained it became evident that any type of liquid phase—even a transient liquid phase—can be excluded. The segregation of boron on the SiC grain boundaries has not been confirmed. The investigations have shown the reduction of SiO 2 layers present on the SiC grains and the development of secondary SiC. The microanalytical in-situ results concerning the intermediate and also the final state of sintering as well as the specific roles of the sintering additives boron and carbon are discussed in detail.