| 摘要 |
A method of making a unitary silicon nitride comprising object is disclosed. A uniform powder mixture is prepared of Si3N4 containing SiO2 as an oxide surface coating, 4-12% by weight Y2O3, and 0.50-2.5% Al2O3. The mixture is heated to 1000 DEG -1400 DEG C. under a pressure of at least 2,000 psi for a time of at least one minute but sufficient to permit a nucleating reaction to take place in secondary phases. Heating is then increased to a temperature of 1680 DEG -1750 DEG C. under a pressure and for a period of time sufficient to produce 99.0% or more of full theoretical density in the pressed object.
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