Investigation on the influence of a titanium coating on the aging behavior of ATZ ceramics for implant applications

The aim of this investigation was to determine the influence of a metallic coating on the LTD behavior of an ATZ ceramic. Therefore, a 300 mu m thick titanium layer was deposited by plasma spraying on a commercial ATZ ceramic containing 20 wt% alumina and 80 wt% 3Y-TZP. After aging the coated and uncoated samples in water vapor at 134. C and 2 bar for 5 h and 30 h, respectively, the monoclinic phase content was determined using Xray diffraction, and its impact on the mechanical properties was assessed in biaxial flexural strength tests. The results revealed an increase in strength with increasing aging time. Furthermore, the Ti-VPS-coating slows down the aging of the ceramic because it acts as a diffusion barrier for the hydroxide ions. As a result, after 30 h of aging, the monoclinic phase content of the coated samples is up to 30% lower than of the uncoated samples.