Characterization of CaO-SiO2-B2O3 glass-ceramics and effect of composition on bioactivity

The sintering behavior, mechanical properties and bioactivity of (50-x/2)CaO.SiO2-xB(2)O(2) (4.2less than or equal toxless than or equal to17.2) glass-ceramics was investigated. The glass-ceramics consisted of three phases, monoclinic-wollastonite, calcium borate and an amorphous borosilicate matrix. Some glass-ceramics sintered at 750-830degreesC for 2h, has produced a nearly pore-free microstructure. The mechanical strength of the dense specimens was higher than that 2 of other bioactive ceramics, compressive strength, 2813MPa and fracture toughness, 3.12MPa.m(1/2). Bioactivity of the glass-ceramics depends on the amount of CaB2O4 and borosilicate glass matrix. The glass-ceramic with more CaB2O4 and borosilicate glass exhibited better bioactivity. It might be likely that more soluble CaB2O4 increases the supersaturation of Ca ions in the SBF solution and water-corrosive borosilicate glass forms Si-OH groups that act as nucleation sites for the hydroxycarbonate apatite (HCA) layer.