Journal of the European Ceramic Society vol:22 issue:6 pages:873-881
Y2O3/Al2O3-coated monoclinic ZrO2 nanopowder was prepared from a suspension of aluminiumnitrate, yttriumnitrate and ZrO2 powder in an alcohol/water mixture. The influence of the Y2O3 and Al2O3 content as well as the sintering temperature on the mechanical properties of the densified yttria-stabilised tetragonal zirconia polycrystal (Y-TZP) materials was investigated. Fully dense Y-TZP materials could be obtained from the Y2O3/Al2O3-coated starting powders by means of hot pressing in vacuum at 1450 degreesC. Typical HV10 hardness values of 1130 kg/mm(2) were obtained and the fracture toughness could be tailored up to 9 MPa m(1/2) by doping the 1.75-2.0 mol% Y2O3-coated ZrO2 starting powders with 2.0 wt. % of Al2O3. The properties and microstructures of the Y2O3/Al2O3-coated powder based ceramics are compared with those of conventional co-precipitated 2Y and 3Y-TZP ceramics, and the differences in fracture toughness are explained in terms of the differences in the grain size and Y2O3 distribution. (C) 2002 Elsevier Science Ltd. All rights reserved.