초록 ▼

A silicon aluminium oxynitride product having the crystal lattice structure of silicon oxynitride but of expanded cell dimensions is produced by sintering a powder mixture of 50 to 60 wt % of Si3N4, 22 to 35 wt % SiO2, 1 to 20 wt % Al2O3 and 1 to 15 wt % of at least one oxide of Y, Li, Mg, Ca, Sc, C

A silicon aluminium oxynitride product having the crystal lattice structure of silicon oxynitride but of expanded cell dimensions is produced by sintering a powder mixture of 50 to 60 wt % of Si3N4, 22 to 35 wt % SiO2, 1 to 20 wt % Al2O3 and 1 to 15 wt % of at least one oxide of Y, Li, Mg, Ca, Sc, Ce or another rare earth element, the molar ratio of SiO2 to Si3N4 being greater than 1:1 and the percentages being based on the total weight of the ingredients. Sintering is effected at 1600°to 1900°C. in a non-oxidizing atmosphere so that the Al2O3, said at least one oxide and part of the SiO2 in the mixture react to form a liquid phase from which silicon aluminium oxynitride having an expanded silicon oxynitride crystal lattice is crystallized. The sintered material is cooled to form a product containing said silicon aluminium oxynitride and at least one grain boundary phase containing silicon and the metal(s) of said at least one oxide.

대표청구항 ▼

A silicon aluminium oxynitride product containing from 80% to 98% by weight of O′-phase silicon aluminium oxynitride as a first phase and 20% to 2% by weight of at least one second phase which contains silicon and at least one metal other than silicon or aluminium, said percentages being based on th

A silicon aluminium oxynitride product containing from 80% to 98% by weight of O′-phase silicon aluminium oxynitride as a first phase and 20% to 2% by weight of at least one second phase which contains silicon and at least one metal other than silicon or aluminium, said percentages being based on the total weight of said first and second phases, said product being from about 85% to about 99% of theoretical density and having a microstructure which is a crystallised network of said O′-phase silicon aluminium oxynitride with said at least one second phase as a grain boundary phase.