Researcher: Dr Claudia Walter

Supervisor: Professor Eduardo Saiz

Funding: CASC

Dr Claudia Walter, working with Eduardo Saiz and in collaboration with Professor Mike Reece at Queen Mary College, is developing ceramic-carbon composites with complex hierarchical structures inspired by nature by combining freeze casting and spark plasma sintering.

The vision is to develop a new family of bio-inspired ceramic-carbon composites where the ceramic will play the role of the mineral phase in nacre or bone and the carbon (in the form of graphite or nanotubes) will be the equivalent to the linking proteins. In this way we plan to emulate the unique confluence of toughening mechanisms exhibit by natural materials, extending it to technical structural ceramics that will exhibit unique combinations of strength and fracture resistance.

A freeze casting set-up for the controlled freezing of ceramic suspensions has been built. The freezing conditions can be controlled to promote the formation of lamellar ice to template the fabrication of porous ceramic layered scaffolds with layer thickness changing between 5 to 100 µm. These scaffolds are infiltrated with carbon precursors or carbon nanotubes are grown in situ in the pores. Conditions for the spark plasma sintering that lead to the formation of layered composites mimicking nacre structure in which ceramic layers separated by thin carbon films have been determined. Future work will focus on the structural and mechanical characterization of this new family of materials.