Research And Application Of MgAlON Composites

Single-phase synthesis and properties of MgAlON materials are researched by using the traditional sintering methods, and the impact of parameters for the synthesis of bauxite-based single-phase MgAlON on the microstructure of the material is also studied. To reduce production costs and decrease firing temperature, MgO powder is added in raw material to reduce its sintering temperature, and the products was MgAlON. To study the microstructure of products, AlN was substituted by Al to further nitridate, bauxite by Al₂O₃ powder and Al₂O₃ powder by nano-Al₂O₃ powder. Air was introduced to replace the N₂ atmosphere and the carbon black was introduced to replace Al to conduct experiment of burying carbon powder sintering. At last the best plan for MgAlON synthesis is got. Meanwhile its performance is detected.The aim of this paper is to explore the potential applications of AlON in the field of refractory materials. The influence of solid solution of MgO on ALON is one of the innovative work. The investigation shows that only when the addition amout of MgO was 8%(wt), the relative content of N, Al and AlN reach max content at the same time, and the effect for synthesis of MgAlON was the best. From the economic effect, the program of bauxite carbonizing in the air is more suitable for industrial production. Combining the condition of buried carbon and nitrogen, the single-phase MgAlON can be synthesised at a relatively low temperatures when nano-Al₂O₃ powder was used in MgAlON synthesis.The results of anti-oxidation measures for MgAlON materials show that the type and addition methods of the antioxidant have a marked influence on the anti-oxidation effect. When the antioxidants is addde in a single form, the anti-oxidation effect of B4C is the best, followed by metal powder Si. SiC played an ineffective role. The composition of antioxidant effect with B4C and metal Si is better than a single antioxidant.The addition of MgAlON in Al₂O₃-SiC-C iron ditch castable was studied. When the adding amount of MgAlON is less than 15 percent, apparent bulk porosity, compressive strength, modulus of rapture and the performance of slag resistance are improved, but construction performance did not changed significantly.