| 摘要 |
PURPOSE:To simplify a structure of a device and to facilitate discharge of synthesized powder from a synthesizing chamber by inserting a powder discharging pipe into the synthesizing chamber of powdery silicon nitride and providing also a gas discharging hole provided with a damper. CONSTITUTION:A powder discharging pipe 5 is inserted into a synthesizing chamber 16, and a gas discharging hole 2 provided with a damper 3 is attached. A valve 9 and the gas discharging hole 2 are opened and granulated raw material in the hopper 4 is charged to the synthesizing chamber 16, and the temp. of gaseous N2 atmosphere in the synthesizing chamber 16 is held at ca.1,300-1,500 deg.C. Gaseous N2 at high temp. and high pressure is blown from a gaseous N2 introducing pipe 15, and granulated particles are reduced and nitrided to produce synthesized silicon nitride powder 17. In this stage, unreacted N2 and produced gas are discharged from a gas discharging hole 2 and invasion of reacted powder 17 into the discharging pipe 5 is prevented by blowing gaseous N2 through a gas introducing pipe 9a. When the synthetic reaction is completed, the valve 9 and the gas discharging hole 2 are closed and a gas venting valve 13 are opened to blow-in high pressure N2 from a N2 introducing pipe 15. Synthesized powder 17 is discharged quickly together with the gas stream through a gas discharging pipe 5 into a powder collecting device 10. The gas is discharged through a valve 13 and the synthesized powder 17 is stored in the device 10. |
