Tough and damage-tolerant monolithic zirconia ceramics with transformation-induced plasticity by grain-boundary segregation. Issue 5 (May 2023)

• Record Type: Journal Article
• Authors: Li, Maoyin; Tunca, Bensu; Van Meerbeek, Bart; Vleugels, Jef; Zhang, Fei
• Is Part Of: Journal of the European Ceramic Society. Volume 43:Issue 5(2023)
• Page Start: 2078
• Page End: 2092
• Publication Date: 2023-05
• Subjects: Ceria stabilized zirconia -- Grain boundary segregation -- Reliability -- Transformation-induced plasticity -- Damage tolerance; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2022.11.069
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: Conventional ceria-stabilized tetragonal zirconia (Ce-TZP) with modest flexural strength has rarely been used as compared to yttria-stabilized zirconia, even though it has excellent hydrothermal stability and high toughness. Ce-TZP-based composites were recently developed, being tough and remarkably in combination with transformation-induced plasticity. However, distinct from the widely applied composite approach to improve the strength of Ce-TZP, in this study, a simpler and easily tailorable method was proposed by doping aliovalent oxides that are able to segregate at the zirconia-grain boundaries. 0.2–1 mol% divalent oxides with different cation size (Mg 2+, Ca 2+, Ba 2+ and Sr 2+ ) were selected to dope 10 mol% ceria-stabilized zirconia. CaO and MgO dopants were able to enter the tetragonal Ce-TZP lattice and showed a grain-boundary segregation effect, thereby tailoring the microstructure and transformation behavior. At a higher dopant concentration of 1 mol% MgO or CaO, the ceramics were strong but brittle with a typical elastic linear fracture behavior, whereas at a low dopant concentration of 0.1–0.2 mol% CaO or 0.2–0.4 mol% MgO doping, the ceramics deformed in-elastically to a certain degree without changing the Young's modulus. At the transition between both fracture behaviors, the best combination of toughness (>10 MPa m 1/2 ), biaxial strength (≥1200 MPa), reliability (Weibull modulus up to 30) and damage-tolerance was obtained. In-situ fracture testing revealed that transformation in such tough and deformable zirconia ceramics took place well before crack initiation with a large transformation zone of ∼100 µm ahead of the crack tip having been formed before failure. Graphical Abstract: ga1