Production and characterization of hydroxyapatite zirconia composites

Hydroxyapatite (HA) is the mineral component of natural hard tissues such as bone structure of which makes up about %70 and essentially all of the enamel in teeth. Hydroxyapatite is regarded to be a bioactive material. It seems to be the most appropriate ceramic material for artificial bones or teeth due to its excellent biocompatibility and bioactivity. Also, HA actively encourages bone regeneration at the surface of the implant hence it has been studied extensively as a candidate biomaterial for its use in orthopedic applications. However, the main weakness of this material lies in poor mechanical properties. HA exhibits low fracture toughness due to its lack of strength and brittleness. This restricts its usage for some applications which need load bearing. On the other hand, zirconia and its alloys have been studied due to its high strenght, fracture toughness and good biocompatibility. Because of that, it is thinking that zirconia by being biocompatible material, when added to HA could improve mechanical properties. The aim of this study is; reinforcing hydroxyapatite with zirconia in order to gain composites have higher mechanical properties. In this study, HA is produced from tooth only by single calcination. Hydroxyapatite powders is mixed with different propotions of zirconia and composites are produced.Composites are sintered in different temperature degree and examined mechanical properties and determined appropriate temperature degree for good mechanical properties.