Mechanical Behaviour of Yttria- and Ferric Oxide-Doped Zirconia at Different Temperatures

Abstract: The variation of strengh, deformability, fracture toughness and other characteristics of partially stabilized zirconia ceramics (Y–Fe–PSZ) doped with 3 % yttrium and 3 % ferric oxide over a temperature range from ÿ140 to 1400C were investigated. Fracture toughness (K1c) values obtained by the methods such as SENB, SEPB, IS and IF were compared. Lower temperatures resulted in an increase in fracture toughness by approximately 29%. Using the Vickers indents as stress concentrators for the IS tests we derived the relationship between K1c values and mean values of radial crack length described by a second-degree polynomial. The data for zirconia (Y–PSZ and Mg–PSZ) and silicon-nitride ceramics, as well as the fractographic data, were used to analyse the results. It was established that the addition of ferric oxide exerted a positive eect on the strengh and fracture toughness of zirconia ceramics. # 1998 Elsevier Science Limited and Techna S.r.l.