二氧化硅微粉对炭素捣打料显微结构及性能的影响

Effects of microsilica addition on the microstructure and properties of carbon material

以冶金焦粉为主要原料,改性中温沥青粉为结合剂,添加二氧化硅微粉混合成型,于220℃下干燥、1 550℃下埋炭烧成炭素捣打料。测定烧成样的耐压强度、体积密度和导热系数,采用XRD和SEM分析试样物相及显微结构。结果表明,添加了二氧化硅微粉的试样经1 550℃热处理,可原位反应生成碳化硅晶须,二氧化硅微粉初期添加量越大,所生成的碳化硅晶须越多,试样的体积密度、耐压强度和导热系数越高;当二氧化硅微粉添加量为8.5%时,试样的碳化硅晶须生成量减少,导热系数降低。

Carbon material was prepared by using waste coke powder as main raw material,modified middle temperature asphalt powder as binder,and microsilica as additive,which were mixed,molded,dried at 220 ℃,embedded in carbon and then fired at 1 550 ℃ for 3 h.The main physical properties of the specimens after firing were investigated,and the phase composition and microstructure of the specimens were characterized by XRD and SEM.The results show that,in-situ synthesized SiC whisker can be generated in the specimens sintered at 1 550 ℃,and with the microsilica addition increasing,the SiC whisker increases.Consequently,the bulk density and compressive strength of the specimensincrease,andthethermalconductivityimproves,butwhentheadditionofmicrosilicais8.5%,the SiC whisker decreases and the thermal conductivity of the specimens decreases.