EFFECT OF TWOSTEP SINTERNG ON MICROSTRUCTURAL ANDMECHANICAL PROPERTES OF ALUMNA ZIRCONA HYDROXTAPATTENAN0C0MP0SITE

Hydroxyapatite HAp;Ca10(PO4)6(OH)2) being chemically similar to the inorganic constituent of bone mineral and owing to its excellent biocompatibility, has been studied extensively as a bone replacement material but the use of HAp is limited to low load bearing application due to its inferior mechanical properties (especially fracture toughness) compared to bone. Hence, additions of second-phase ceramic materials to the HAp matrix to obtain products with enhanced strength and toughness has been an interesting subject matter of research in recent years. Zirconia and Alumina have been commonly used as reinforcement, because of their high strength, fracture toughness and bioinertness properties. This work reports on the effect of tow-step sintering on mechanical and microstructural properties of HAp/ZrO2-Al2O, nanocomposites. After densification, the mechanical properties, the relative proportion of TCP formed and the microstructures of the composite were observed. By used of two step sintering, highest hardness and fracture toughness, lowest relative proportion of TCP and nanostructure were achieved.

Keywords:

tow-step sintering , HAp/ZrO2-Al2O3 nanocomposites , microstructural properties , hardness and fracture toughness