NSIC silicon nitride stalk tube cover of themercouple NSiC Electic Heating Protection Tubes for Aluminum Melting Application Advanced NSiC electric heating protection tubes are widely used at metallurgy & foundry area because of the advantage of anti-corrosion, resistance to chemical & abrasive attack, thermal shock resistance, acid & alkali resistance & no Fe added etc. NSiC can contact directly with non-ferrous metal fluids at high working temperature. The strength is high with long serving lives.