Enhanced mechanical performance of in–situ Mg–sialon in low–carbon MgO–C refractories through Si–Al4SiC4 additions.

In this study, a novel MgO–C refractory, fabricated through high–temperature nitriding, was developed by incorporating Si–Al 4 SiC 4 to in–situ form plate–like Mg–sialon ceramic bonding phase in situ. The influences of Al 4 SiC 4 content and nitriding temperature on the phase transformation, microstructure, and mechanical properties of MgO–C refractories were examined. The synergistic effect of Si co–existed with Al 4 SiC 4 promoted the in–situ formation of plate–like Mg–sialon, thereby accelerating the densification of MgO–C refractories. The primary crystal growth surface for Mg–sialon was identified as the (100) facet. The plate–like Mg–sialon was integrally bonded within the matrix, enhancing the interfacial bonding with MgO particles, rather than merely adhering to the surface. The incorporation of 2 wt% Al 4 SiC 4 significantly optimized the microstructure of MgO–C refractories, culminating in superior mechanical properties when nitrided at 1400 °C. Furthermore, the formation mechanism and morphological evolution of the plate–like Mg–sialon in MgO–C refractories were explored. • Novel in–situ Mg–sialon enhanced low–carbon MgO–C refractories have been developed. • The coexistence of Si with Al 4 SiC 4 synergistically facilitated the in-situ formation of plate-like Mg-sialon. • The addition of 3 wt% Si and 2 wt% Al 4 SiC 4 demonstrated optimal properties for the novel refractories. • The thermodynamics of the nitridation process was simulated and calculated. • Mg–sialon formation occurs predominantly through a solution–precipitation mechanism. [ABSTRACT FROM AUTHOR]