Toughening of hot-pressed ZrSiO4 ceramics by addition of Y-TZP

Zircon (ZrSiO4) ceramics were toughened by Y-TZP particles stabilized with different contents of yttria. The mechanical properties of zircon ceramics were improved in varying degrees, depending on the amount of Y-TZP added and the content of stabilizer Y2O3. When 20 vol% of 3 mol% Y-TZP was introduced into the zircon matrix, the flexural strength and fracture toughness reached 410 +/- 20 MPa and 4.3 +/- 0.4 MPa m(1/2), respectively, which is about 40% higher than the values of monolithic zircon ceramics. Based on the results of XRD analysis and TEM observation, it is argued that microcracking toughening mechanism existed in all Y-TZP/ZrSiO4, composites while the effect of phase transformation toughening increased as the content of Y2O3 was raised from 0 to 3 mol%. (C) 1998 Elsevier Science B.V. All rights reserved.