Fracture Behavior of a Hydroxyapatite-Metal Interface Jointed by Hydrothermal Hot-pressing Method(Ceramics & Rocks 1)

Abstract

Solidificatioin of hydroxyapatite (HAp) and its bonding with titanium (Ti) was achieved simultaneously by using a hydrothermal hot-pressing method at the low temparaure as low as 150℃. A mixture of calcium hydrogen phosphate dihydrate and calcium hydroxide was used as a starting powder material for solidifying HAp. The joining behavior of HAp and Ti depended on the surface finishing condition of the titanium. From Raman spectroscopy of the Ti surfaces, it was found that TiO_2 formed at the Ti surface affected the bonding characteristics of the HAp/Ti interface. 3-point bending tests were conducted to obtain an estimate of the fracture toughness for the HAp/Ti interface as well as for the HAp ceramics only. Core-based specimens were used for the fracture toughness tests and a pre-crack was introduced along the HAp/Ti interface of the bonded specimens. The fracture toughness tests showed that the induced crack from the pre-crack tip deviated from the HAp/Ti interface and propagated into the HAp. The fracture toughness determined on the HAp/Ti specimen was closed to that of the HAp ceramics only (〜0.30MPa).