原位生成非氧化物对刚玉基浇注料性能的影响

为了进一步提高刚玉基浇注料的高温使用性能,在超低水泥刚玉浇注料中加入质量分数分别为0、4%、6%、8%、10%的硅粉,经振动浇注成型、养护、烘干后,在氮气气氛中于1 450℃氮化处理40 h,测定试样的加热永久线变化及烧后试样的显气孔率、体积密度、常温抗折强度和不同温度(分别为1 000、1 200、1 300和1 400℃)下的热态抗折强度,并对部分氮化后试样进行XRD和SEM分析。结果表明:1)随着硅粉加入量的增加,试样在氮化处理过程中从发生微收缩到发生微膨胀,显气孔率略有增大,体积密度和常温抗折强度下降,热态抗折强度显著提高;2)氮化处理后,试样中原位生成了非氧化物β-SiAlON、O’-SiAlON和α-Si3N4等。

Effects of in-situ synthesized non-oxides on properties of corundum castables

Silicon powder(0,4%,6%,8% and 10% in mass) was added into ultra low cement corundum castables to improve their high temperature performance.The castables were vibrating-cast,cured,dried,and fired at 1 450 ℃ for 40 h in nitrogen atmosphere.The permanent change in dimensions on heating,apparent porosity(AP),bulk density(BD),cold modulus of rupture(CMOR),and hot modulus of rupture(HMOR) at 1000,1200,1300 and 1400 ℃,respectively,were determined.The specimens were investigated by XRD and SEM.The results show that:(1)with the increase of Si powder addition,the specimens vary from mild shrinkage to mild expansion during the nitridation,AP slightly increases,CMOR and BD decrease,and HMOR of corundum castables after nitridation is obviously improved;(2)after nitridation,the non-oxides such as β-SiAlON,O’-SiAlON and α-Si3N4 are in-situ formed.