WordNet records no synonym and no antonym for silicon carbide. It is the only member of its synset, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
an extremely hard blue-black crystalline compound (SiC) used as an abrasive and a heat refractory material; crystals of silicon carbide can be used as semiconductors
Synonyms, antonyms and the broader and narrower relations for silicon carbide come from Princeton University’s WordNet. Full sources and licences.