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分别以复合还原剂铝碳,单一还原剂铝、碳还原氮化铝土矿(Al2O3含量为68%)(文中含量均为质量分数)制备β-SiAlON。利用XRD、SEM和EDS等检测手段和试样在1 100～1 550℃温度范围的质量变化率,研究了制备β-SiAlON的相变过程和铝碳复合还原剂对生成β-SiAlON的含量和显微结构的影响。结果表明:1 100℃时,铝粉氮化形成AlN,同时铝粉还原二氧化硅生成Si;1 200℃时,Si和氮气反应生成Si3N4;1 300～1 350℃,还原剂碳参与还原反应,β-SiAlON开始生成;1 400～1 550℃时,进入固溶阶段,β-SiAlON量增多,1 550℃时含量达到最高。与单一还原剂相比,铝碳复合还原剂制备的β-SiAlON的晶体截面形态呈长柱状,结晶发育较好。
The β-SiAlON was prepared by using composite reductant aluminum carbon, single reductant aluminum and carbon-reduced bauxite (Al2O3 content of 68%). The phase change of β-SiAlON and the content of β-SiAlON and the content of β-SiAlON were studied by XRD, SEM and EDS, and the mass change rate of the sample in the temperature range of 1 100-1 550 ℃. Effect of microstructure. The results show that when Al is formed at 100 ℃, AlN is formed by the nitridation of aluminum powder and Si is reduced by aluminum powder. At 1200 ℃, Si reacts with nitrogen to form Si3N4. At 1300 ~ 350 ℃, reductant carbon participates in the reduction reaction , β-SiAlON began to form; 1 400 ~ 1 550 ℃, enter the solution phase, β-SiAlON increased, 1 550 ℃ content reached the highest. Compared with the single reductant, the crystal morphology of β-SiAlON prepared by aluminum carbon composite reductant has a long columnar shape and the crystal development is better.