材料期刊网

为了进一步完善中间包用镁质弥散型透气元件的性能，以电熔镁砂颗粒（粒度1～0．5、1．5～0．5和2～1 mm）、高纯镁砂粉（≤0．074 mm）、铝镁尖晶石粉（≤0．074 mm）、α-Al2 O3粉（≤0．074 mm）为主要原料，亚硫酸纸浆废液为结合剂，按不同的粒度级配（配料中≤0．074 mm 的细粉质量分数分别为6％、13％、20％和27％）配料、混料后经机压成型，然后经1650℃下保温3 h 烧成制备了镁质弥散型透气试样，并研究了镁砂临界粒度（分别为1、1．5和2 mm）和颗粒级配对试样透气度、高温抗折强度、体积密度和显气孔率、常温抗折强度、常温耐压强度以及显微结构中气孔孔径的影响。结果表明：随着镁砂颗粒临界粒度的增加，试样的常温强度、高温抗折强度和体积密度均减小，气孔率和透气度增大；随着配料中≤0．074 mm 细粉含量的增加，试样的常温强度、高温抗折强度、体积密度均增大，气孔率和透气度减小。综合各项性能认为，电熔镁砂骨料（粒度为1～0．5 mm）含量为80％（w），细粉（≤0．074 mm）含量为20％（w），是镁质弥散型透气材料的最佳配比。

To further improve the properties of magnesia dispersive purging components for tundish,fused magnesia particle (1 -0.5,1.5 -0.5,and 2 -1 mm),high purity magnesia powder (≤0.074 mm),magne-sium aluminate spinel powder (≤0.074 mm),α-Al2 O3 powder (≤0.074 mm)were used as the main raw materials,and sulphite lye as the binder,batched in different particle size distribution (the fines ≤0.074 mm account for 6%,13%,20%,and 27%,respectively,by mass),mixed,machine-pressed,and then fired at 1 650 ℃ for 3 h to prepare magnesia dispersive purging specimens.The effects of critical particle size (1,1.5,and 2 mm)and particle size distribution of magnesia on permeability,hot flexural strength,bulk density,apparent porosity,cold flexural strength,cold crushing strength,microstructure,and medium pore size of magnesia dispersive purging materials were studied.The results show that with the increase of the critical particle size of the magnesia,cold strength,hot flexural strength and bulk density decrease,the po-rosity and permeability increase;with the increase of the content of fines ≤0.074 mm,the cold strength,hot flexural strength and bulk density increase,porosity and permeability decrease.Considering the compre-hensive performance,the optimal formulation is 80% fused magnesia aggregate (particle size 1 -0.5 mm) and 20% fines(≤0.074 mm)for magnesia dispersive purging materials.