Progress in the application of nanotechnology to magnesia refractories

Magnesia refractories are promising high-temperature structural materials known for their high melting point, excellent high-temperature stability, and promising mechanical properties, which make them suitable for numerous high-temperature applications in steel manufacturing, metallurgy, building materials, and ceramics. However, traditional magnesia refractories do not meet the requirements established for advanced refractories. Low-carbon magnesia carbon refractories have several disadvantages, including poor slag and thermal shock resistances, owing to their reduced carbon content. Magnesia calcia refractories have poor hydration resistance due to the presence of free calcium oxide. Moreover, magnesia alumina refractories have poor sintering and mechanical properties owing to their volumes and thermal expansion mismatch. Therefore, the techniques used to prepare high-performance magnesia refractories have attracted widespread attention. Recently, nanotechnology has emerged as a promising new technology that is widely used improve refractory yield and in many other applications because of its excellent surface properties, small size, quantum dimensions, and macro quantum effects. The preparation of magnesia composite refractories using nanotechnology relieves the demand for high-performance magnesia refractories by high-temperature industries and also contributes to the development of lightweight and functional value-added products. Therefore, the use of nanotechnology in the preparation of magnesia composite refractories has great significance for the enhancement of their properties. In this paper, the research status and progress of nanotechnology in recent years with respect to the damage mechanisms in low-carbon magnesia–carbon refractories, magnesia calcia refractories, and magnesia alumina refractories in China and overseas were reviewed. In addition, the interaction mechanisms were analyzed, the challenges and developments in the application of nanotechnology were discussed.