Influence of Silicon Nitride on Properties of Corundum Based Castable
The effects of Si3N4 addition on the room temperature physical properties and thermal shock resistance properties of corundum based refractory castables were investigated using brown corundum, white corundum and alumina micropowder as the starting materials and pure calcium aluminate as a binder. The phase composition, microstructure, mechanical properties of corundum based castables were investigated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that as the increase in Si3N4 addition, the bulk density decreased and apparent porosity increased, the cold strength deduced. However, the residual strength rate increased. That is, the thermal shock resistance was improved. This is because even though the introduction of Si3N4 inhibited the sintering of material and deduced the compactness, microcracks were produced in the materials due to a difference in thermal expansion coefficient. So the thermal shock resistance of corundum based castable was improved.
Jianmin Zeng, Hongxi Zhu and Jianyi Kong
J. C. Wei and L. R. Yang, "Influence of Silicon Nitride on Properties of Corundum Based Castable", Advanced Materials Research, Vols. 634-638, pp. 2358-2361, 2013