Research on high-temperature creep properties of Al2O3-MgAl2O4 refractory

In this study, the Al2O3-MgAl2O4 refractory samples were prepared with tabular alumina and fused magnesia-alumina spinel as the raw materials. A creep resistance test was performed at 1400 degrees C and studied. The tested samples after the creep resistance test were characterized and analyzed by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy to investigate the effect of adding the amount and particle size of MgAl2O4 on high-temperature creep resistance of Al2O3-MgAl2O4 refractory, as well as its mechanism. As indicated by the results, under the same amount of spinel added, the sample with 3-1 mm spinel had higher creep resistance than the sample with 1-0 mm spinel. In the creep test, spinel aggregates would react with the alumina matrix to form a secondary spinel layer around the spinel particles, thereby connecting the matrix and the aggregates and improving the creep resistance of the specimens. As clearly indicated by the observed result of the microstructure, in the formation of the secondary spinel layer, Mg2+ had a higher migration rate and showed the secondary spinel layer's higher thickness ratio on both sides of the reaction interface, which would induce the Kirkendall effect. Accordingly, considerable pores generated and accumulating at the interface tended to reduce the creep resistance of the material, and this effect was highly dependent on the size of the spinel and the activation solid solution reaction intensity.