Mechanical behaviour of yttria- and ferric oxide-doped zirconia at different temperatures

The variation of strengh, deformability, fracture toughness and other chara cteristics of partially stabilized zirconia ceramics (Y-Fe-PSZ) doped with 3% yttrium and 3% ferric oxide over a temperature range from -140 to 1400 d egrees C were investigated. Fracture toughness (K-1c) values obtained by th e methods such as SENB, SEPB, IS and IF were compared. Lower temperatures r esulted in an increase in fracture toughness by approximately 29%. Using th e Vickers indents as stress concentrators for the IS tests we derived the r elationship between K-1c, values and mean values of radial crack length des cribed by a second-degree polynomial. The data for zirconia (Y-PSZ and Mg-P SZ) and silicon-nitride ceramics, as well as the fractographic data, were u sed to analyse the results. It was established that the addition of ferric oxide exerted a positive effect on the strengh and fracture toughness of zi rconia ceramics. (C) 1998 Elsevier Science Limited and Techna S.r.l.