SETT ATT FRAMSTELLA ETT FOREMAL AV KISELNITRID GENOM ISOSTATISK PRESSNING AV EN AV KISELNITRIDPULVER FORFORMAD KROPP MED ETT GASFORMIGT TRYCKMEDIUM I ETT TRYCKKERL VID EN FOR SINTRING AV KISELNITRIDEN ERFORDERLIG ...

摘要

Disclosed is an improved method for manufacturing an object of silicon nitride. In the method, a body preformed from silicon nitride powder and enclosed in a casing of glass is isostatically pressed with a gaseous pressure medium in a pressure vessel at a temperature required for sintering of silicon nitride. After pressing and sintering are completed, the pressure and the temperature in the pressure vessel are adjusted such that the temperature maintains the glass in a plastic state and the pressure in the pressure vessel is below the partial pressure of nitrogen gas for silicon nitride at that temperature so that the glass casing is blown up around the body and the body is freed from or can easily be freed from the glass casing.