Hydroxyapatite-silk Functionally Graded Material by Pulse Electric Current Sintering

This research was intended to produce functionally graded material (FGM) of Hydroxyapatite (HA)-silk fibroin by pulse electric current sintering in facing the need in biomaterial application. Silk film was utilized as a bound between each layer. The target sample thickness was 1.6 mm with diameter 15 mm. Sample that was created by using cylindrical type of carbon die was consist of 4 layers with the same thickness for each layer and between the layer was inserted a silk film (thickness was 100 m). The composition of lower layer was 100% silk fibroin, after that 90% silk fibroin +10% HA for second layer, third layer was 80% silk fibroin+20% HA, and 70% silk fibroin+30% HA for the upper layer. The properties of all FGM product were characterized by optical microscope, scanning electron microscope (SEM), and three point bend with single-edge beam for fracture toughness test (KIC). The grade of the FGM material was proven by using electron probe micro analyzer (EPMA). The value of fracture toughness was found at 0.651 MPa.m1/2. The silk film in the borders of the sample could arrest the crack perfectly, so that sudden fracture can be avoided. The sample still capable to support the load after maximum load was reached. Result from optical micrograph and SEM indicated that the Hap-silk fibroin FGM could be produced successfully by using the method that was introduced in this research. © Society for Biomaterials and Artificial Organs (India), 20070930-12 .