Enhanced mechanical properties of ZrO 2 -Al 2 O 3 dental ceramic composites by altering Al 2 O 3 form

This study evaluates the difference in physical and mechanical properties of ZrO ceramics, commonly used in dental applications, altered by three different forms of Al O content; microparticles (m), nanoparticles (n), and microfiber (f). Three different types of ZrO -Al O composites were formed using microparticle (m), nanoparticle (n), or microfibre (f) forms of Al O . The physical and mechanical properties such as sintering shrinkage, relative density, Vickers hardness, fracture toughness, and biaxial strength were evaluated. A Weibull analysis was performed to assess the strength reliability of the specimens. All data were calculated using the t-test and ANOVA. The sintering shrinkage and relative density of all ceramic composite groups were decreased with the addition of Al O . The mechanical properties of ZrO -Al O (f) composite were higher than that of ZrO -Al O (m) composite and ZrO -Al O (n) composite. The maximum hardness, fracture toughness, and biaxial flexural strength were observed for 10 vol% of Al O fibre. When the content of Al O fibre in the matrix was increased above 20 vol%, agglomeration occurred and resulted in a decrease of hardness and toughness. The Weibull modulus value of the ZrO -Al O (f) composite was the lowest compared to that of other groups. However, characteristic strength (σ ) of ZrO -Al O (f) the highest value. The current study demonstrated that the addition of right amount of Al O microfibre into the ZrO matrix enhanced the mechanical properties of ZrO -Al O (f) composite, which would be favourable for dental applications.