Tough and Strong Ce-TZP/Alumina Nanocomposites Doped with Titania

To develop a new attractive Ce-TZP ceramic, which possesses a high strength while still preserving significant high toughness, we investigated an intragranular type of nanocomposite in lower CeO₂ content for 0-1 mol% TiO₂ doped Ce-TZP/Al₂O₃ system. These composites partly possessed an intragranular microstructure, in which several of 10 100 nm sized Al₂O₃ particles were trapped within the ZrO₂ grains. Furthermore, elongated Al₂O₃-like phases were produced at the ZrO₂ grain boundaries, which were in-situ precipitated during the sintering process. TiO₂ was confirmed to dissolve into the tetragonal ZrO₂ lattice, which was determined to be effective for strengthening with a slight addition due to its grain growth enhancing ability on ZrO₂. For an optimum component with 0.05 mol% TiO₂ doped 10Ce-TZP/30vol% Al₂O₃ composite, both high strength (950 MPa) and high toughness (18.3MPa.m^1/2 for the IF method, 9.8MPa-m^1/2 for the SEVNB method) were achieved thus breaking through the strength-toughness tradeoff relation in transformation toughened ZrO₂ and its composite materials.