Research Of Al-Cr₂O₃ System Material Synthesized By Self-propagating High-temperature Synthesis

Metal ceramic material prepared by Self-propagating high-temperature synthesis(SHS)has the merits of rapid reaction and simple equipments compared with complex process of conventional process.This paper prepared Al-Cr₂O₃ system insulation material with the method of SHS.The Al-Cr₂O₃ system insulation material is synthesized by the SHS reaction in the Al-Cr₂O₃ mixture system ingnited by electric current in the experiments.The reaction process is concrolled by dilution agent Al₂O₃ and addition agent NaF in the reacting hybrid.The effects of the percentage of Al₂O₃,addition of NaF,particle size of Al powder and preheating temperature are also studied in this research.According to general theory of statistics, calculations based on the resulets of the experiments are used to obtain the optimal batching scheme of preparing this material in the experimental conditions of this research.Measuring methods such as SEM,XRD are used to measure and analyse the reaction products.The adiabatical temperature of theory obtained by doing thermodynamic calculation is 2836.275K,which proves the experimental feasibility.The effects the dilution agent Al₂O₃ and accessory substance AlN are analysed in the section of thermodynamic calculation according to reaction system.The results show that the large amount of heat absorbed by dilution agent Al₂O₃ degrades the adiabatical temperature sharply while the heat delivered by the generation of accessory substance AlN improves the SHS reaction.The optimal batching scheme of preparing Al-C1₂O₃ system insulation material obtained by optimizing the experimental scheme and calculating as follows:The reacting hybrid(wt%):Al₂O₃(32%),Cr₂O₃(42.7%),Al(25.3%); The addition agent NaF(g):2.1g/(100g hybrid of reacting material). The measuring results based on the experiments show:the cold crushing strength is 26MPa,and refractoriness is higher than 1800℃.The Al-Cr₂O₃ system insulation material prepared in this research whose both performances above are more excellent than conventional insulating materials are more appropriate for actual prpduction.