title: Subcritical crack growth behavior of dispersion oxide ceramics.
abstract: Zirconia (Y-TZP) is used as material for components of implants and prostheses because of its high short-term strength. The mechanical long-term reliability, however, is limited for Y-TZP because of hydrothermal aging effects and a pronounced tendency for subcritical crack growth. The hypothesis of this study was that a substantial amount of alumina in a zirconia matrix can help to significantly suppress subcritical crack growth and thereby improve the mechanical long-term reliability. The Weibull parameters as well as the parameters of the subcritical crack growth were determined for Alumina, Y-TZP, and two dispersion ceramics, that is Alumina Toughened Zirconia (ATZ, 20% alumina/80% Y-TZP), and Zirconia Toughened Alumina (ZTA, 75% alumina/25% Y-TZP). The long-term failure probability as a function of service time was predicted for the four ceramics. The parameter n of the subcritical crack growth was approx. 80% higher for ATZ compared to Y-TZP. In consequence, the estimated lifetime revealed a significant better mechanical long-term reliability for ATZ. It can be concluded that tailored dispersion oxide ceramics can address the aging problem of monolithic zirconia. This makes ATZ very interesting for components of joint replacement as well as for dental prostheses and implants.
authors.affiliation: Department of Dental Materials and Biomaterials Research, University Hospital Aachen, Pauwelsstrasse 30, 52074 Aachen, Germany.
authors.forename: Armin
authors.initials: A
authors.lastname: Kirsten
authors.forename: Sabine
authors.initials: S
authors.lastname: Begand
authors.forename: Thomas
authors.initials: T
authors.lastname: Oberbach
authors.forename: Rainer
authors.initials: R
authors.lastname: Telle
authors.forename: Horst
authors.initials: H
authors.lastname: Fischer
mesh_terms: D000537:Aluminum Oxide; D002516:Ceramics / Q000737:chemistry* / Q000592:standards; D015921:Dental Implants; D007595:Joint Prosthesis; D008422:Materials Testing; D015019:Yttrium; D015040:Zirconium
chemical_list: D015921:Dental Implants; C499362:yttria stabilized tetragonal zirconia; D015019:Yttrium; D015040:Zirconium; D000537:Aluminum Oxide