Preparation and characterization of ZnO modified solid state sintered 45S5 bioactive ceramics

Abstract

In this research, the traditional 45S5 bioactive glass powder was modified using ZnO (<20 μm) by powder metallurgy route. Five different bioactive ceramics compositions (45BC, 45BC1, 45BC3, 45BC5 and 45BC7) were formulated containing varied amounts of ZnO in the step of 1, 3, 5 and 7 wt % respectively. Each body was thoroughly mixed in a porcelain-lined ball mill to ensure proper homogenization followed by an addition of prepared 2 % PVA (Polyvinyl alcohol) and then again thoroughly mixed. The batch material was uniaxially pressed at 70 MPa using a cylindrical mould of 40 × 20 mm. A total of 20 samples from each body composition were produced and allowed to dry in an ambient temperature followed by sintering at 1000 °C for 2h at the rate of 5 °C/min. The samples were then allowed to anneal within the furnace to room temperature. Selected samples were later immersed inside simulated body fluid. Physical, mechanical, microstructure and phase evaluation were conducted to examine the developed bioactive ceramics. The results showed that the bulk density increased from 1.6 to 2.64 g/cm3 while porosity decrease from 95 % to 58 % across the series, with increasing ZnO addition. Sample 45BC7 showed maximum hardness and compressive strength of 7.98 GPa and 83.54 MPa respectively. The carbonate-hydroxyapatite/hydroxyapatite (CHA/HA) deposits were found to also increased with ZnO addition showing good bioactivity, which affirms that the developed bioactive ceramics can bond well with living tissues, thus its suitability for bone regeneration.