| 摘要 |
<p>Converting Si to beta-phase Si3N4 comprises: (a) heating a walled container contg. Si while traversing through a first heated zone (C1) of a furnace having a hydrogen atmos.and temp. up to 1000 [deg] C to burn off organic additives, (b) heating the container while traversing through a second heated zone (C2) having a temp. of 1350-1450 [deg] C and a nitriding atmos. to form an alpha-phase Si3N4 mass, (c) heating the container while traversing through a third heated zone (C3) for a sufficient time to convert the alpha-phase Si3N4 to beta-phase Si3N4, the third heated zone having an atmos. contg. nitrogen and a temp. of 1450-2100 [deg] C, and (d) cooling the container contg. beta-phase Si3N4 in a cooling zone (E) of the furnace at a rate of 250-1250 [deg] C per hour. The walled container is formed from a Si3N4-contg. material that is stable at temps. of at least 1700 [deg] C and has an opening to allow placement of the non-densified alpha-phase Si3N4 mass therein.</p> |
