Fracture toughness improvement of zirconia based ceramics

The study explores the approach to the synergism of several mechanisms for increasing the fracture toughness of zirconia-based ceramics: transformation toughening by means of martensitic tetragonal-monoclinic transition, hardening by introducing reinforcing nanotubes and creating conditions for the implementation of the Cook–Gordon mechanism on weak matrix-inclusion interface. The subject of the study were ceramic composite materials based on yttrium-stabilized tetragonal zirconia, multi-walled carbon nanotubes, and hexagonal boron nitride particles. Fracture toughness studies were performed using the Vickers indentation and SEVNB methods. The study results have shown that the implementation of three mechanisms of crack front energy dissipation at the same time is possible and, in some cases, it leads KIC increasing by an order of 30%.