Physicomechanical Properties of Porous Zirconia Ceramics

Resumo

The influence of porosity on the mechanical properties of zirconia ceramics in dynamic nanocontact is studied by the Oliver–Pharr method and continuous stiffness measurement. Oscillations with an amplitude up to 8 nm are found not to affect the harmonic stiffness of poreless ceramic. However, the presence of pores causes a dependence of the Oliver–Pharr hardness, elastic modulus, harmonic stiffness, and strength on the porosity and the indentation depth. Oscillations with an amplitude of 2 nm or larger lead to the softening of porous ceramic. In contrast to dense and low-porosity ceramics, the stiffness and the hardness of ceramic with 38% porosity increase during the penetration of an indenter rather than decreasing.