Liquid-phase-sintered SiC shaped bodies with improved fracture toughness and a high electric resistance

A polycrystalline SiC shaped body comprising 96% by weight to 99.5% by weight of a hard-material phase;

• 0 to 0.1% by weight free carbon;
• remainder a partially crystalline binder phase;
• the hard-material phase comprising SiC and a Si—C—Al—O—N mixed crystal, containing 0.2 to 1.5% by weight dissolved aluminum, 0.1 to 0.5% by weight dissolved nitrogen, 0.01 to 0.2% by weight dissolved oxygen,
• the hard material phase comprising globular grains with a mean grain size of <4 μm, at least three grains enclosing a triple junction
• the globular grains having a structure comprising a core and a shell surrounding the core, the core comprising SiC and the shell comprising a Si—C—Al—O—N mixed crystal, the mixed crystal having an Al/N atomic ratio of 1.0:1.0 to 2.0:1.0, and
• the partially crystalline binder phase comprising crystalline and amorphous phases of the rare earth metal —Al—Si—O quaternary system, the amorphous phase being present in the form of a grain boundary film which surrounds the globular grains, and the crystalline phase being present in form of accumulations at the triple junctions comprising rare earth aluminate.