Ytterbia (2·25 mol.-%) stabilised zirconia (Yb-TZP) manufactured from coated nanopowder

Abstract

Rare earth stabilised tetragonal zirconia polycrystals (TZPs) with stabilisers other than yttria and ceria are scarcely examined as structural ceramics. Unstabilised pyrogenic zirconia nanopowder was coated with 2·25 mol.-% of ytterbium oxide via the nitrate route. Yb-TZP ceramics were consolidated by hot pressing in vacuum at 1200–1400°C for 1 h at 60 MPa axial pressure. Mechanical properties, phase composition and microstructure were investigated. 2·25Yb-TZP exhibits a unique combination of very high strength (>1500 MPa), hardness [1300 HV10] and toughness (>9 MPa m1/2). Mechanical properties vary only slightly with variation of processing conditions. The material exhibits very high stress induced transformability from tetragonal to monoclinic of >60%. Yb-TZP may thus be an interesting alternative material to Y-TZP for high value adding applications requiring the best possible mechanical properties such as biomedical or mechanical engineering.