A strong and damage-tolerant oxide laminate

A novel laminar oxide composite was developed. This oxide laminate, which was fabricated by hot pressing, consisted of three types of layers, which were stacked in a repeating sequence of YPO₄, yttria-stabilized ZrO₂, 30 vol% yttria-stabilized ZrO₂-70 vol% Al₂O₃, and yttria-stabilized ZrO₂. The behavior of the oxide laminate was evaluated by four-point flexural testing and the indentation technique. The flexural strength from one test was 358 MPa, and the load-displacement curve of this test displayed a graceful failure. Pronounced interfacial delamination contributed to a high work of fracture and damage tolerance. These properties have rarely been observed in oxide composites and are comparable to those of non-oxide composites, such as SiC/graphite, SiC/BN, and Si₃N₄/BN laminates.