Zirconia–multiwall carbon nanotubes dense nano-composites with an unusual balance between crack and ageing resistance

Yttria stabilized zirconia (Y-TZP) ceramics are used in a wide variety of applications, such as orthopaedic and dental implants. Y-TZP offers indeed a unique combination of biocompatibility and mechanical properties (high crack resistance for a ceramic). However, the major drawback of Y-TZP is their lack of stability: zirconia is prone to ageing, especially under humid atmosphere. Increasing the ageing resistance of Y-TZP led so far to a decrease of toughness and crack resistance. Here we show that the addition of a small volume fraction of multiwall carbon nanotubes (MWCNT) in a polycrystalline nano-structured Y-TZP sintered under specific conditions (Spark Plasma Sintering) leads to a material exhibiting a balance between ageing and crack resistance never reached before.