Moulded body with a long life hard coating made of silicium nitride, method for its manufacture and its application

摘要

Moldings comprise a substrate and a hard coating. This comprises up to 75 wt% of silicon nitride and at least 25% of an inorganic binder. The total oxygen content of the coating is above 15 wt%. Independent claims are included for: (A) a method for making the moldings by applying a coating as specified to a substrate; (B) use of the moldings in corrosive non-ferrous metal technology; and (C) their use as riser tubes in low pressure casting of aluminum.