Hydroxyapatite Formation and Strength of Cellular Alumina Coated with Bioactive Glass

초록

Many works have been done to produce cellular form of bioactive ceramics for used by a scaffold. But, low compressive strength of these materials is been the major problem. In this study, therefore, a cellular form of alumina was first made by using poly-urethane sponge technique, and followed by coating bioactive glass on it to give a bioactivity. Poly-urethane sponge with 30ppi (pores per inch) were soaked in alumina slurry, and slurry in sponge was removed that used by a centrifugal separator, and controlled closed pores. The green body that made by these method was fired at 1550℃. Two kinds of glasses, such as, ground coat glass and bioactive glass, were coated on cellular alumina. The compressive strength of the cellular alumina was measured, and the behavior of the hydroxyapatite formation on the bioactive glass-coated alumina was characterized after reacted in simulated body fluid (SBF). The compressive strength of cellular alumina increased as the number of coating increase, because frame was hardened. Also, it's compressive strength be enhanced by infiltrating the ground coat glass into micro-pores in alumina skeleton and, develops a maximum strength of 3 times. The bioactive glass coat layer on the cellular alumina crystallized into α-wollastonite and β-wollastonite when heat-treated at 1200℃ and 1100℃, respectively. Hydroxyapatite developed when these samples were reacted in SBF. It's forming rate was higher in the samples heat-treated at 1200℃, due to the higher releasing rate of Ca2+ ions from the α-wollastonite than from the β-wollastonite crystal.