Waste to shield: Tailoring cordierite/mullite/zircon composites for radiation protection through controlled sintering and Y2O3 modification

Abstract

In this study, investment casting shell waste successfully utilized to produce cordierite/mullite/zircon composites. Green pellets, consisting of investment casting shell waste, alumina, and magnesia, were prepared and sintered at temperatures between 1250 and 1350 °C. The influence of the sintering temperature on the crystalline phase composition, densification behavior, flexural strength, microstructure, and radiation shielding properties of the cordierite/mullite/zircon composites is investigated. Phase analysis showed that characteristic cordierite peaks appear at 1250 °C, but the complete conversation of silica from investment casting shell waste into cordierite requires a sintering temperature of at least 1300 °C. Notably, the cordierite/mullite/zircon composite sintered at 1350 °C exhibited a sixfold increase in flexural strength compared to the ceramic composite directly fabricated from investment casting shell waste at the same sintering temperature. Furthermore, the effect of Y2O3 addition on composites' radiation shielding properties is investigated. The results show that the Y2O3 addition improved densification behavior, enhancing the shielding capabilities of the composites against fast neutron and gamma radiation. Our findings suggest that the developed ceramic composites show significant potential for gamma-ray and neutron shielding applications.