Preparation and characterization of glass–ceramic under various sintering atmospheres

• A novel method for preparing iron rich glass–ceramic.
• Iron rich steel slag is potential for producing glass–ceramic under N2 and CO atmospheres.
• CO sintering atmosphere could lower the crystallization temperature by ~20 °C.
• Reductive and inert atmospheres could enhance the mechanical properties of products.

The iron rich glass–ceramics were prepared by cold pressing sintering method under various atmospheres. Microstructure evolution and crystalline phase transition of glass ceramics were investigated by field emission scanning electron microscopy and X-ray diffraction. The influence of sintering atmosphere on crystallization behaviour was carried out by differential thermal analysis experiment. The results indicate that the akermanite and gehlenite, in the form of spherical or granular, uniformly distribute in the glass matrix as samples sintered in N2 and CO (10 vol% CO, 90 vol% N2, 60 mL/min) atmospheres. The corresponding nucleation and crystallization temperatures are both reduced by ~20 °C. Moreover, the main mechanical properties of glass samples sintered in CO and N2 atmospheres are improved as compared with air ones, and the performance of samples sintered in CO (Bending strength 55 MPa, micro-hardness 3.6 GPa) is much better. This research is of special interest for the utilization of steel slag and energy saving.