| 摘要 |
PCT No. PCT/EP96/05571 Sec. 371 Date Jun. 10, 1998 Sec. 102(e) Date Jun. 10, 1998 PCT Filed Dec. 12, 1996 PCT Pub. No. WO97/21644 PCT Pub. Date Jun. 19, 1997By providing a new method of producing sintered silicon nitride, this invention takes into account the fact that parts made of Si3N4 are often used in temperature ranges below 1200 DEG C. and sometimes even below 500 DEG C. and therefore needn't be designed to withstand temperatures above 1200 DEG C. The sintered silicon nitride for these low-temperature applications is obtained by sintering silicon nitride powder of <2 mu m with 5 to 20 wt. % of one or more glass components of the same particle size at temperatures below 1400 DEG C. It is a prerequisite that the glass components used, preferably alkali metal borate glasses with a coefficient of thermal expansion alpha which matches that of Si3N4, have a transformation point Tg which is below 750 DEG C., and that the individual glass components have a free enthalpy DELTA G which is at least 60% of the free enthalpy of SiO2. For low-temperature applications, Si3N4 parts manufactured cost-effectively in this way fully satisfy the demands made on them in respect of density, strength and beta -phase proportion.
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