Method of making shaped silicon nitride articles

Abstract

Abstract Reaction-bonded silicon nitride Si3N4 is produced by starting from pure silicon powder or from a powder mixture of pure silicon and its nitride. This is subjected to cold-isostatic pressing or to a slip-casting or die-casting process, before it is transferred into a hot-isostatic press. The reaction is initiated under a nitrogen pressure of initially 0.5 - 2.0 MPa and an initial temperature of 1000 DEG C. During the reaction, the pressure is increased to 4.9 MPa and the temperature is increased to at most 1420 DEG C. This increase in pressure and temperature is effected at least partially in stages. This gives a product of a degree of nitriding of more than 92%. The process permits shaped articles having a wall thickness of more than 10 mm to be produced within a cycle time of less than 24 hours, the material being nitrided evenly.

Inventors

• 👤 Beat Hofer
• 👤 Bernhard Einstein

Bibliographic Details