Low-Temperature Degradation Behaviour and Mechanical Properties of a 3Y-TZP Manufactured from Detonation-Synthesized Powder

In recent years, yttria-stabilized zirconia Y-TZP has attracted considerable interest in the field of dental restoration. However, the state-of-the-art Y-TZP materials made from coprecipitated powders only just comply with the current standard in terms of fracture resistance and grain size. In this study a new nanoscale starting powder produced with detonation synthesis was applied to produce a fully dense specimen by means of hot pressing in the sintering temperature range between 1250 - 1500 degrees C. Mechanical properties, microstructure and phase composition were studied. Low temperature degradation behavior was quantified in an accelerated ageing test in a saturated water vapor at 134 degrees C. Between sintering temperatures of 1300 degrees C and1400 degrees C, the materials obtained show a combination of high strength > 1400 MPa, toughness of 6 MPa root m and fine grain size < 320 nm and thus fulfill the requirements of the dental standard EN ISO 6872. Ageing resistance was high. After nucleation of the monoclinic content, the materials exhibited zero-order growth kinetics and retained > 90 % tetragonal phase up to ageing times of 10 h approximate to 35 years in vivo.