Assertion: polycrystalline ceramic | /r/ObjectUse | used for silicon carbide
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Source sentences:
text: Alumina ceramics are used for missile and rocket nose cones, silicon carbide (SiC) and molybdenum disilicide (MoSi 2 ) are used in rocket nozzles, and ceramic tiles are used for thermal insulation to protect the Space Shuttle on re-entry through the Earth's atmosphere.