Ashley will complete her PhD at the University of Cambridge this year as a Marshall Scholar and National Science Foundation Graduate Research Fellow. Her work has focused on the development of carbon nanotube-reinforced hydroxyapatite. She finished her undergraduate studies in 2005 at Virginia Tech, USA, in Materials Science and Engineering and Music Performance (violin).

Carbon Nanotube-Reinforced Hydroxyapatite: the Sintering Challenge

Hydroxyapatite (HA) is a biologically active ceramic used in clinical bone graft procedures. Unfortunately, its poor tensile strength and fracture toughness have prevented its use in major load-bearing devices. Carbon nanotubes (CNTs), with their excellent mechanical properties, have the potential to strengthen and toughen HA, expanding the range of clinical uses for the material. However, certain challenges arise in combining these materials to form a dense composite.

This lecture will focus on one of those challenges – selecting an appropriate sintering atmosphere. Studies have shown that the presence of water in the atmosphere is required to retain HA’s hydroxyl groups, which impacts its bioactivity. However, water leads to the oxidation of CNTs at the high temperatures needed to obtain a dense ceramic, and thus the reinforcing phase is lost. This lecture will examine results from sintering in several specially-designed atmospheres, including the effects on composition, hydroxylation and CNT retention.