| AlN is known as a representative of advanced ceramics associated with its high melting point, good thermal conductivity, low thermal expansion and excellent stableness to the molten steel, so it is a potential candidate for new refractories with good chemical resistance and thermal shock resistance. Considering that MgO/AIN composites are fabricated by traditional processes using A1N powder as raw materials, their production cost is too high to meet the demand for the application into metallurgical industry. MgO/AIN composites will be prepared by Al alloy welt infiltration into MgO preforms with the aim of establishing a novel process for the refractories in this paper.This paper can be mainly divided into two parts: one part focuses on the preparation of A1N/A1 composites by Al alloy directed nitridation; Another part focuses on the fabrication of MgO/AIN composites by Al alloy melt infiltration into MgO preforms.At the first part, AlN/Al composites fabricated by Al alloy directed nitridation are discussed thermodynamically. Furthermore, the phase compositions and microstructure of Al alloy fused in our laboratory are detected and observed by XRD and SEM. The influence of processing parameters such as temperature and Mg, Si alloy elements on the preparation of A1N/A1 composites is investigated and its reaction mechanism is discussed.At the second part, the influence of processing parameters, such as temperature, MgO preforms particle, soaking time and Mg, Si elements doped into Al alloy on the phase composition and microstructure of MgO/AIN composites is investigated. Also, the main reactions occurring in above process are discussed in order to establish a reaction model.In addition, two experiments are designed to confirm the possible reactions in above processes in the first experiment. MgAl2O4 and A^Os preforms are selected in comparison with MgO performs. In the second, the different content of MgO powder is mixed into Al compacts, which are heated in nitrogen atmosphere.
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