Abstract:

Ordinary MgO-C specimens MC (flake graphite addition of 9%,by mass) and MgO-Ti₃AlC₂-C specimens MC-3AC (flake graphite addition of 4% and Ti₃AlC₂ addition of 3%,by mass) were prepared using sintered magnesia,flake graphite,Si powder,and Ti₃AlC₂ powder as the main raw materials,and phenolic resin as the binder.After mixing,shaping,drying at 110 ℃ and curing at 220 ℃,the specimens were heat treated at 1 100,1 400 and 1 600 ℃ for 3 h in carbon embedded condition.The apparent porosity,the cold modulus of rupture,the elastic modulus and the oxidation resistance at 1 100,1 300 and 1 500 ℃ in air atmosphere were detected and XRD analysis was conducted.The results show that:(1) after curing at 220 ℃,specimens MC-3AC have lower apparent porosity and much higher cold modulus of rupture and elastic modulus than specimens MC;(2) after carbon embedded heat treatment at 1 100-1 600 ℃,specimens MC-3AC have lower apparent porosity and higher cold modulus of rupture and elastic modulus than specimens MC;(3) when oxidized at 1 100 and 1 300 ℃,specimens MC-3AC have worse oxidation resistance than specimens MC and specimens MC-3AC oxidized at 1 500 ℃;however,when oxidized at 1 500 ℃,specimens MC-3AC have better oxidation resistance than specimens MC.

Key words: Ti₃AlC₂, magnesia-carbon refractories, oxidation resistance, mechanical properties

摘要：

以烧结镁砂、鳞片石墨、Si粉、Ti₃AlC₂粉为主要原料,以酚醛树脂为结合剂,配制成w(鳞片石墨)=9%的普通MgO-C试样MC和w(鳞片石墨)=4%、w(Ti₃AlC₂)=3%的MgO-Ti₃AlC₂-C试样MC-3AC,经混练、成型、110 ℃干燥、220 ℃固化后,在埋碳条件下分别于1 100、1 400和1 600 ℃保温3 h热处理。检测试样的显气孔率、常温抗折强度、弹性模量和1 100、1 300、1 500 ℃空气气氛下的抗氧化性,并进行了XRD分析。结果表明:1)在220 ℃固化后,试样MC-3AC的显气孔率比试样MC的小,常温抗折强度和弹性模量比试样MC的大得多。2)在1 100~1 600 ℃埋碳热处理后,试样MC-3AC的显气孔率比试样MC的小,常温抗折强度和弹性模量均比试样MC的大。3)在1 100 和 1 300 ℃氧化时,试样MC-3AC的抗氧化性比试样MC的差,也比1 500 ℃时试样MC-3AC的差;但在1 500 ℃氧化时,试样MC-3AC的抗氧化性比试样MC的好。

关键词: Ti₃AlC₂, MgO-C材料, 抗氧化性能, 力学性能