The Effects of Chitosan Addition on Joining Behaviour of Hydroxyapatite Ceramics and Titanium by Hydrothermal Hot-pressing

抄録

Solidificatioin of hydroxyapatite (HA:Ca₁₀(PO₄)₆(OH)₂) and its bonding with titanium (Ti) was achieved simultaneously by using a hydrothermal hot-pressing method at the low temparaure as low as 150 degrees C.A mixture of calcium hydrogen phosphate dehydrate(DCPD) and calcium hydroxide was used as a starting powder material for solidifying HA. Chitosan was mixed in DCPD with co-precipitation method.3-point bending tests were conducted to obtain an estimate of the fracture toughness for the HA/Ti interface as well as for the HA ceramics only. The fracture toughness tests showed that the induced crack from the pre-crack tip deviated from the HA/Ti interface and propagated into the HA. The fracture toughness determined on the bonded HA/Ti specimen was close to that of the HA ceramics only (With chitosan: 0.40MPam^1/2, without chitosan: 0.30MPam^1/2). This enhancement of fracture toughness of HA could not be achieved unless using co-precipitation method.