| 摘要 |
<p>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 65 wt% of Si<Sub>3</Sub>N<Sub>4</Sub>, 22 to 35 wt% Si0<Sub>2</Sub>, 1 to 20 wt% Al<Sub>2</Sub>O<Sub>3</Sub> 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 Si0<Sub>2</Sub> to Si<Sub>3</Sub>N<Sub>4</Sub> 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-oxidising atmosphere so that the Al<Sub>2</Sub>O<Sub>3</Sub>, said at least one oxide and part of the Si0<Sub>2</Sub> in the mixture react to form a liquid phase from which silicon aluminium oxynitride having an expanded silicon oxynitride crystal lattice is crystallised. 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.</p> |
