Effect of Sintering Aid Composition on the Processing of Si3N4/BN Fibrous Monolithic Ceramics
نویسندگان
چکیده
Si3N4/BN fibrous monoliths were prepared with 4 wt% Y2O3 added as a sintering aid to the Si3N4. Residual carbon, present in the billet before hot-pressing, was shown to influence the final microstructure. The sintering aid glass, known to migrate into the BN cell boundaries during hotpressing, was not sufficient in quantity to prevent premature shear failure when samples were tested in flexure. Increasing the hot-pressing temperature alleviated this problem. For flexure samples tested at 1400°C, fibrous monoliths fabricated with 4 wt% Y2O3 demonstrated linear-elastic loading behavior at a greater stress than fibrous monoliths fabricated with 6-wt%-Y2O3/2-wt%-Al2O3 sintering aids.
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