Properties of zirconia-toughened mullite ceramics improved by B2O3 additive

Abstract

Zirconia-toughened mullite (ZTM) ceramics has been prepared by using an electrically fused mullite as a raw material and its mechanical properties and microstructure as a function of impurities in the raw material were studied. These impurities led to a decrease in the mechanical properties of ZTM ceramics by changing the properties of the glassy phase in the ceramics, especially at high temperature. The mechanical properties of the ceramics were improved by adding B2O3, and the toughness at room temperature increased from 4.4 MPa m1/2 to 5.9 MPa m1/2 while that at 800°C increased from 2.9 MPa m1/2 to 4.4 MPa m1/2. The toughness of the ceramics on the addition of B2O3 at room temperature was increased by 34% and that at 800°C by 52%. The influence of the impurities on the ZTM ceramics and the improvement of the ceramic properties by the addition of B2O3 were studied and their mechanisms were discussed.