原位尖晶石引入量对MgAl2O4-SiC材料性能的影响

在以预合成镁铝尖晶石、碳化硅和水性氨基树脂为原料制备MgAl2O4-SiC复合材料的配方中,以不同量的MgO、α-Al 2O3混合粉(MgO、Al2O3物质的量比为1∶1)等量替代其中的预合成镁铝尖晶石粉,设计替代量(w)分别为0、1%、2%、3%、4%、6%、8%、10%。经配料、混练、成型、干燥后,在埋碳条件下于1650℃保温5 h烧成,然后检测烧后试样的显气孔率、体积密度、常温耐压强度、常温抗折强度和高温抗折强度,并进行XRD和SEM分析。结果表明:1)随着原位MgAl2O4引入量的增加,试样的致密度和强度均呈先增大后减小的变化趋势,原位镁铝尖晶石引入量为3%(w)的试样的致密度最大,原位镁铝尖晶石引入量为4%(w)的试样的强度最大。2)各试样的物相组成基本相同,主要物相为MgAl2O4和SiC。

Effect of in-situ synthesized spinel addition on properties of MgAl2O4-SiC refractories

In the formulations of MgAl 2O 4-SiC composites with pre-synthesized magnesium aluminate spinel,silicon carbide,and waterborne amino resin as the starting materials,different amounts of MgO andα-Al 2O 3 mixed powder(n(MgO)∶n(Al 2O 3)=1∶1)was used to replace the pre-synthesized magnesium aluminate spinel powder in equal amounts(0,1%,2%,3%,4%,6%,8%,and 10%,by mass,respectively).After batching,mixing,molding,drying,and firing at 1650℃for 5 h with carbon embedded,the specimens were obtained.Then the apparent porosity,the bulk density,the cold compressive strength,the cold modulus of rupture,and the hot modulus of rupture of the specimens were tested,and the XRD and SEM analyses were carried out.The results show that:(1)with the increase of the in-situ MgAl 2O 4 addition,the density and the strength of the specimens increase first and then decrease;the density of the specimen with 3%of in-situ MgAl 2O 4 is the largest,and the strength of the specimen with 4%of in-situ MgAl 2O 4 is the highest;(2)the phase composition of all specimens is basically the same,and the main phases are MgAl 2O 4 and SiC.