Processing of Layered Hydroxyapatite Ceramic Composites
Layered hydroxyapatite (HA) based ceramic composites consisting of a strong ceramic composite core, 3 mol% yttrium stabilized zirconia (3Y-TZP) with 30 or 40 vol% HA, and a HA-rich porous coating were fabricated using a coating deposition and co-sintering process in the present study. The aim is to develop HA-based bio-ceramic composites that retain the bio-compatibility of HA and the preferred scaffold structure, but have much improved structural properties required for implants. Two different coating techniques, sol-gel derive HA coating and HA solution coating, have been used to deposit the HA coating on the strong HA-containing 3Y-TZP core, which has been pre-sintered at 900°C and has a green-machined surface finish. The upper limit for the final sintering of the layered ceramic composites is set at 1,350°C based on the individual sintering properties of HA and 3Y-TZP. SEM observations have been conducted on the coating surface, sectioned surface of coating and substrate/core to characterize the microstructures of coating and substrate and their interface. Preliminary mechanical tests and XRD tests are also performed to characterise the structural properties at different temperatures.
George Ferguson, Ashvin Thambyah, Michael A Hodgson and Kelly Wade
R. Sultana et al., "Processing of Layered Hydroxyapatite Ceramic Composites", Advanced Materials Research, Vol. 275, pp. 143-146, 2011